U.S. patent application number 11/549499 was filed with the patent office on 2008-04-24 for controller for a motor and a method of controlling the motor.
This patent application is currently assigned to A.O. SMITH CORPORATION. Invention is credited to Ronald P. Bartos, Brian Thomas Branecky, Howard Richardson.
Application Number | 20080095639 11/549499 |
Document ID | / |
Family ID | 39032383 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080095639 |
Kind Code |
A1 |
Bartos; Ronald P. ; et
al. |
April 24, 2008 |
Controller for a motor and a method of controlling the motor
Abstract
A pumping apparatus for a jetted-fluid system includes a pump
having an inlet connectable to the drain, and an outlet connectable
to the return. The pump is adapted to receive the fluid from the
drain and jet fluid through the return. The pumping apparatus
includes a motor coupled to the pump to operate the pump, a sensor
connectable to the power source and configured to generate a signal
having a relation to a parameter of the motor, and a switch coupled
to the motor and configured to control at least a characteristic of
the motor. The pumping apparatus also includes a microcontroller
coupled to the sensor and the switch. The microcontroller is
configured to generate a derivative value based on the signal, and
to control the motor based on the derivative value.
Inventors: |
Bartos; Ronald P.;
(Menomonee Falls, WI) ; Branecky; Brian Thomas;
(Oconomowoc, WI) ; Richardson; Howard;
(Springfield, OH) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH LLP
100 E WISCONSIN AVENUE, Suite 3300
MILWAUKEE
WI
53202
US
|
Assignee: |
A.O. SMITH CORPORATION
Milwaukee
WI
|
Family ID: |
39032383 |
Appl. No.: |
11/549499 |
Filed: |
October 13, 2006 |
Current U.S.
Class: |
417/44.11 |
Current CPC
Class: |
F04D 15/0066 20130101;
F04D 15/00 20130101; F04D 15/0055 20130101; F04D 15/0236
20130101 |
Class at
Publication: |
417/44.11 |
International
Class: |
F04B 49/06 20060101
F04B049/06 |
Claims
1. A pumping apparatus for a jetted-fluid system comprising a
vessel for holding a fluid, a drain, and a return, the pumping
apparatus being connectable to a power source and comprising: a
pump including an inlet connectable to the drain, and an outlet
connectable to the return, the pump adapted to receive the fluid
from the drain and jet fluid through the return; a motor coupled to
the pump to operate the pump; a sensor connectable to the power
source and configured to generate a signal having a relation to a
parameter of the motor; a switch coupled to the motor and
configured to control at least a characteristic of the motor; and a
microcontroller coupled to the sensor and the switch, the
microcontroller configured to generate a derivative value based on
the signal, and to control the motor based on the derivative
value.
2. The pumping apparatus of claim 1, wherein the microcontroller is
configured to calculate a value indicative of the parameter, and to
generate the derivative value based on the value.
3. The pumping apparatus of claim 1, wherein the sensor includes a
voltage sensor configured to generate a first signal having a
relation to a voltage applied to the motor, and a current sensor
configured to generate a second signal having a relation to a
current applied to the motor, and wherein the microcontroller is
configured to generate the derivative value based on the first
signal and the second signal.
4. The pumping apparatus of claim 1, wherein the sensor includes a
voltage sensor and a current sensor, the parameter includes a motor
input power, and the derivative value includes a derivative value
of the motor input power.
5. The pumping apparatus of claim 4 wherein the microcontroller is
configured to determine the motor input power based on signals from
the voltage and current sensors, and to determine the derivative
value based on the motor input power.
6. The pumping apparatus of claim 1, wherein the parameter includes
a motor torque, and the derivative value includes a derivative
value of the motor torque.
7. The pumping apparatus of claim 1, wherein the parameter includes
a motor power factor, and the derivative value includes a
derivative value of the motor power factor.
8. The pumping apparatus of claim 1, wherein the microcontroller is
further configured to monitor the derivative value, determine
whether the monitored derivative value indicates an undesired flow
of fluid through the pump, and control the motor to cease operation
of the pump when the determination indicates an undesired flow of
fluid through the pump and zero or more other conditions exist.
9. A pumping apparatus for a jetted-fluid system comprising a
vessel for holding a fluid, a drain, and a return, the pumping
apparatus being connectable to a power source and comprising: a
pump including an inlet connectable to the drain, and an outlet
connectable to the return, the pump adapted to receive the fluid
from the drain and jet fluid through the return; a motor coupled to
the pump to operate the pump; a sensor coupled to the motor and
configured to generate a signal having a relation to a power of the
motor; a switch coupled to the motor and configured to control at
least a characteristic of the motor; and a microcontroller coupled
to the sensor and the relay circuit, the microcontroller configured
to generate a derivative value of a parameter based on the signal,
and to control the motor based on the derivative value.
10. The pumping apparatus of claim 9, wherein the microcontroller
is configured to calculate a value indicative of the parameter, and
to generate the derivative value based on the value.
11. The pumping apparatus of claim 9, wherein the sensor includes a
voltage sensor configured to generate a first signal having a
relation to a voltage applied to the motor, and a current sensor
configured to generate a second signal having a relation to a
current applied to the motor, and wherein the microcontroller is
configured to generate the derivative value based on the first
signal and the second signal.
12. The pumping apparatus of claim 9, wherein the sensor includes a
voltage sensor and a current sensor, the parameter includes a motor
input power, and the derivative value includes a derivative value
of the motor input power.
13. The pumping apparatus of claim 12 wherein the microcontroller
is configured to determine the motor input power based on signals
from the voltage and current sensors, and to determine the
derivative value based on the motor input power.
14. The pumping apparatus of claim 9, wherein the microcontroller
is further configured to monitor the derivative value, determine
whether the monitored derivative value indicates an undesired flow
of fluid through the pump, and control the motor to cease operation
of the pump when the determination indicates an undesired flow of
fluid through the pump and zero or more other conditions exist.
15. A method of controlling a motor operating a pumping apparatus
of a fluid-pumping application, the pumping apparatus comprising a
pump having an inlet to receive a fluid and an outlet to exhaust
the fluid, and the motor coupled to the pump to operate the pump,
the method comprising: sensing a motor current; sensing a motor
voltage; obtaining a derivative value of the motor power based on
the sensed voltage and the sensed current; determining whether the
derivative value indicates a condition of the pump; and controlling
the motor to operate the pump based on the condition of the
pump.
16. The method of claim 15, further comprising obtaining a power
value of the motor power based on the sensed voltage and the sensed
current.
17. The method of claim 15, wherein the condition of the pump is an
undesired flow of fluid through the pump.
18. The method of claim 15, wherein the pumping apparatus further
comprises a voltage sensor and a current sensor, wherein sensing a
motor voltage comprises sensing a voltage applied to the motor with
the voltage sensor, and wherein sensing a motor current comprises
sensing a current through the motor with the current sensor.
19. A pumping apparatus for a jetted-fluid system comprising a
vessel for holding a fluid, a drain, and a return, the pumping
apparatus being connectable to a power source and comprising: a
pump including an inlet connectable to the drain, and an outlet
connectable to the return, the pump adapted to receive the fluid
from the drain and jet fluid through the return; a motor coupled to
the pump to operate the pump; a sensor connectable to the power
source and configured to generate a signal having a relation to a
parameter of the motor; a switch coupled to the motor and
configured to control at least a characteristic of the motor; and a
derivative device coupled to the sensor and the switch, the
derivative device configured to generate a derivative value based
on the signal to control the motor based on the derivative
value.
20. The pumping apparatus of claim 20, wherein the derivative
device includes an operational amplifier circuit.
21. The pumping apparatus of claim 20, wherein the sensor includes
a voltage sensor configured to generate a first signal having a
relation to a voltage applied to the motor, and a current sensor
configured to generate a second signal having a relation to a
current applied to the motor, and wherein the derivative device is
configured to generate the derivative value based on the first
signal and the second signal.
22. The pumping apparatus of claim 20, wherein the sensor includes
a voltage sensor and a current sensor, the parameter includes a
motor input power, and the derivative value includes a derivative
value of the motor input power.
23. The pumping apparatus of claim 20, wherein the parameter
includes a motor torque, and the derivative value includes a
derivative value of the motor torque.
24. The pumping apparatus of claim 20, wherein the parameter
includes a motor power factor, and the derivative value includes a
derivative value of the motor power factor.
25. A pumping apparatus for a jetted-fluid system comprising a
vessel for holding a fluid, a drain, and a return, the pumping
apparatus being connectable to a power source and comprising: a
pump comprising an inlet connectable to the drain, and an outlet
connectable to the return, the pump adapted to receive the fluid
from the drain and jet fluid through the return; a motor coupled to
the pump to operate the pump; a sensor configured to generate a
signal having a relation to a parameter of the motor; a switch
coupled to the motor and configured to control a characteristic of
the motor; and a microcontroller coupled to the sensor and the
switch, the microcontroller configured to generate a value based on
the signal, the value having a relation to the motor torque, and to
control the motor based on the value.
26. The pumping apparatus of claim 25, wherein the sensor is
connectable to the power source.
27. The pumping apparatus of claim 25, wherein the sensor is
coupled to the motor.
28. The pumping apparatus of claim 25, wherein the sensor includes
a current sensor configured to generate a signal related to the
current of the motor.
29. The pumping apparatus of claim 26, and further comprising a
second sensor configured to generate a signal indicative of the
speed of the motor.
30. The pumping apparatus of claim 26, wherein the microcontroller
is further configured to determine the speed of the motor, and
wherein the value has a further relation to the speed of the
motor.
31. The pumping apparatus of claim 27, wherein the microcontroller
is further configured to determine a relationship between the speed
of the motor and the signal related to the current of the motor to
calculate the value.
32. The pumping apparatus of claim 25, wherein the microcontroller
is further configured to monitor the value, determine whether the
monitored value indicates an undesired flow of fluid through the
pump, and control the motor to cease operation of the pump when the
determination indicates an undesired flow of fluid through the pump
and zero or more other conditions exist.
33. A method of controlling a motor operating a pumping apparatus
of a jetted fluid system comprising a vessel for holding a fluid, a
drain, and a return, the pumping apparatus comprising a pump having
an inlet connectable to the drain, and an outlet connectable to the
return, the pump adapted to receive the fluid from the drain and
jet fluid through the return, and the motor coupled to the pump to
operate the pump, the method comprising: controlling the motor to
operate the pump; sensing a current of the motor; calculating a
torque of the motor based on the sensed current; determining
whether the torque indicates a condition of the pump; and further
controlling the motor to operate the pump based on the condition of
the pump.
34. The method of claim 33, wherein monitoring the operation of the
pump further comprises sensing a voltage applied to the motor;
determining a speed value related to the motor; and wherein the
calculating a torque is further based on the speed value.
35. The method of claim 33, further comprising sensing a speed of
the motor; and wherein the calculating a torque is further based on
the sensed speed.
36. The method of claim 33, further comprising calculating a value
indicative of input power to the motor; and determining a linear
relationship between the torque and the input power to the motor.
Description
BACKGROUND
[0001] The invention relates to a controller for a motor, and
particularly, a controller for a motor operating a pump.
[0002] Occasionally on a swimming pool, spa, or similar
jetted-fluid application, the main drain can become obstructed with
an object, such as a towel or pool toy. When this happens, the
suction force of the pump is applied to the obstruction and the
object sticks to the drain. This is called suction entrapment. If
the object substantially covers the drain (such as a towel covering
the drain), water is pumped out of the drain side of the pump.
Eventually the pump runs dry, the seals burn out, and the pump can
be damaged.
[0003] Another type of entrapment is referred to as mechanical
entrapment. Mechanical entrapment occurs when an object, such as a
towel or pool toy, gets tangled in the drain cover. Mechanical
entrapment may also effect the operation of the pump.
[0004] Several solutions have been proposed for suction and
mechanical entrapment. For example, new pool construction is
required to have two drains, so that if one drain becomes plugged,
the other can still flow freely and no vacuum entrapment can take
place. This does not help existing pools, however, as adding a
second drain to an in-ground, one-drain pool is very difficult and
expensive. Modern pool drain covers are also designed such that
items cannot become entwined with the cover.
[0005] As another example, several manufacturers offer systems
known as Safety Vacuum Release Systems (SVRS). SVRS often contain
several layers of protection to help prevent both mechanical and
suction entrapment. Most SVRS use hydraulic release valves that are
plumbed into the suction side of the pump. The valve is designed to
release (open to the atmosphere) if the vacuum (or pressure) inside
the drain pipe exceeds a set threshold, thus releasing the
obstruction. These valves can be very effective at releasing the
suction developed under these circumstances. Unfortunately, they
have several technical problems that have limited their use.
SUMMARY
[0006] In one embodiment, the invention provides a pumping
apparatus for a jetted-fluid system having a vessel for holding a
fluid, a drain, and a return. The pumping apparatus is connected to
a power source and includes a pump having an inlet connectable to
the drain, and an outlet connectable to the return. The pump is
adapted to receive the fluid from the drain and jet fluid through
the return. The pumping apparatus also includes a motor coupled to
the pump to operate the pump, a sensor connectable to the power
source and configured to generate a signal having a relation to a
parameter of the motor, and a switch coupled to the motor and
configured to control at least a characteristic of the motor. The
pumping apparatus also includes a microcontroller coupled to the
sensor and the switch. The microcontroller is configured to
generate a derivative value based on the signal, and to control the
motor based on the derivative value.
[0007] In another embodiment, the invention provides a pumping
apparatus for a jetted-fluid system having a vessel for holding a
fluid, a drain, and a return. The pumping apparatus is connected to
a power source and includes a pump including an inlet connectable
to the drain, and an outlet connectable to the return. The pump is
adapted to receive the fluid from the drain and jet fluid through
the return. The pumping apparatus also includes a motor coupled to
the pump to operate the pump, a sensor coupled to the motor and
configured to generate a signal having a relation to a power of the
motor, and a switch coupled to the motor and configured to control
at least a characteristic of the motor. The pumping apparatus also
includes a microcontroller coupled to the sensor and the relay
circuit. The microcontroller is configured to generate a derivative
value of a parameter based on the signal, and to control the motor
based on the derivative value.
[0008] In another embodiment, the invention provides a method of
controlling a motor operating a pumping apparatus of a
fluid-pumping application. The pumping apparatus includes a pump
having an inlet to receive a fluid and an outlet to exhaust the
fluid, and the motor is coupled to the pump to operate the pump.
The method includes sensing a motor current, sensing a motor
voltage, and obtaining a derivative value of the motor power based
on the sensed voltage and the sensed current. The method also
includes determining whether the derivative value indicates a
condition of the pump, and controlling the motor to operate the
pump based on the condition of the pump.
[0009] In another embodiment, the invention provides a pumping
apparatus for a jetted-fluid system comprising a vessel for holding
a fluid, a drain, and a return. The pumping apparatus is connected
to a power source and includes a pump having an inlet connectable
to the drain, and an outlet connectable to the return. The pump is
adapted to receive the fluid from the drain and jet fluid through
the return. The pumping apparatus also includes a motor coupled to
the pump to operate the pump, a sensor connectable to the power
source and configured to generate a signal having a relation to a
parameter of the motor, and a switch coupled to the motor and
configured to control at least a characteristic of the motor. The
pumping apparatus also includes a derivative device coupled to the
sensor and the switch. The derivative device is configured to
generate a derivative value based on the signal to control the
motor based on the derivative value.
[0010] In another embodiment, the invention provides a pumping
apparatus for a jetted-fluid system having a vessel for holding a
fluid, a drain, and a return. The pumping apparatus is connected to
a power source and includes a pump comprising an inlet connectable
to the drain, and an outlet connectable to the return. The pump is
adapted to receive the fluid from the drain and jet fluid through
the return. The pumping apparatus also includes a motor coupled to
the pump to operate the pump, a sensor configured to generate a
signal having a relation to a parameter of the motor, and a switch
coupled to the motor and configured to control a characteristic of
the motor. The pumping apparatus also includes a microcontroller
coupled to the sensor and the switch. The microcontroller is
configured to generate a value based on the signal, where the value
has a relation to the motor torque, and to control the motor based
on the value.
[0011] In another embodiment, the invention provides a method of
controlling a motor operating a pumping apparatus of a jetted fluid
system having a vessel for holding a fluid, a drain, and a return.
The pumping apparatus includes a pump having an inlet connectable
to the drain, and an outlet connectable to the return. The pump is
adapted to receive the fluid from the drain and jet fluid through
the return, and the motor coupled to the pump to operate the pump.
The method includes controlling the motor to operate the pump,
sensing a current of the motor, and calculating a torque of the
motor based on the sensed current. The method also includes
determining whether the torque indicates a condition of the pump,
and controlling the motor to operate the pump based on the
condition of the pump.
[0012] Other features and aspects of the invention will become
apparent by consideration of the detailed description and
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic representation of a jetted-spa
incorporating the invention.
[0014] FIG. 2 is a block diagram of a first controller capable of
being used in the jetted-spa shown in FIG. 1.
[0015] FIGS. 3A and 3B are electrical schematics of the first
controller shown in FIG. 2.
[0016] FIG. 4 is a block diagram of a second controller capable of
being used in the jetted-spa shown in FIG. 1.
[0017] FIGS. 5A and 5B are electrical schematics of the second
controller shown in FIG. 4.
[0018] FIG. 6 is a block diagram of a third controller capable of
being used in the jetted-spa shown in FIG. 1.
[0019] FIG. 7 is a graph showing an input power signal and a
derivative power signal as a function of time.
[0020] FIG. 8 is a flow diagram illustrating a model observer.
[0021] FIG. 9 is a graph showing an input power signal and a
processed power signal as a function of time.
[0022] FIG. 10 is a graph showing an average input power signal and
a threshold value reading as a function of time.
[0023] FIG. 11 is a graph showing characterization data and fluid
pressure data as a function of flow rate.
[0024] FIG. 12 is a chart showing a numeric relationship between
input power and torque.
DETAILED DESCRIPTION
[0025] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. Unless specified or limited otherwise,
the terms "mounted," "connected," "supported," and "coupled" and
variations thereof are used broadly and encompass direct and
indirect mountings, connections, supports, and couplings. Further,
"connected" and "coupled" are not restricted to physical or
mechanical connections or couplings.
[0026] FIG. 1 schematically represents a jetted-spa 100
incorporating the invention. However, the invention is not limited
to the jetted-spa 100 and can be used in other jetted-fluid systems
(e.g., pools, whirlpools, jetted-tubs, etc.). It is also envisioned
that the invention can be used in other applications (e.g.,
fluid-pumping applications).
[0027] As shown in FIG. 1, the spa 100 includes a vessel 105. As
used herein, the vessel 105 is a hollow container such as a tub,
pool, tank, or vat that holds a load. The load includes a fluid,
such as chlorinated water, and may include one or more occupants or
items. The spa further includes a fluid-movement system 110 coupled
to the vessel 105. The fluid-movement system 110 includes a drain
115, a pumping apparatus 120 having an inlet 125 coupled to the
drain and an outlet 130, and a return 135 coupled to the outlet 130
of the pumping apparatus 120. The pumping apparatus 120 includes a
pump 140, a motor 145 coupled to the pump 140, and a controller 150
for controlling the motor 145. For the constructions described
herein, the pump 140 is a centrifugal pump and the motor 145 is an
induction motor (e.g., capacitor-start, capacitor-run induction
motor; split-phase induction motor; three-phase induction motor;
etc.). However, the invention is not limited to this type of pump
or motor. For example, a brushless, direct current (DC) motor may
be used in a different pumping application. For other
constructions, a jetted-fluid system can include multiple drains,
multiple returns, or even multiple fluid movement systems.
[0028] Referring back to FIG. 1, the vessel 105 holds a fluid. When
the fluid movement system 1 10 is active, the pump 140 causes the
fluid to move from the drain 115, through the pump 140, and jet
into the vessel 105. This pumping operation occurs when the
controller 150 controllably provides a power to the motor 145,
resulting in a mechanical movement by the motor 145. The coupling
of the motor 145 (e.g., a direct coupling or an indirect coupling
via a linkage system) to the pump 140 results in the motor 145
mechanically operating the pump 140 to move the fluid. The
operation of the controller 150 can be via an operator interface,
which may be as simple as an ON switch.
[0029] FIG. 2 is a block diagram of a first construction of the
controller 150, and FIGS. 3A and 3B are electrical schematics of
the controller 150. As shown in FIG. 2, the controller 150 is
electrically connected to a power source 155 and the motor 145.
[0030] With reference to FIG. 2 and FIG. 3B, the controller 150
includes a power supply 160. The power supply 160 includes
resistors R46 and R56; capacitors C13, C14, C16, C18, C19, and C20;
diodes D10 and D11; zener diodes D12 and D13; power supply
controller U7; regulator U6; and optical switch U8. The power
supply 160 receives power from the power source 155 and provides
the proper DC voltage (e.g., .+-.5 VDC and .+-.12 VDC) for
operating the controller 150.
[0031] For the controller 150 shown in FIGS. 2 and 3A, the
controller 150 monitors motor input power and pump inlet side
pressure to determine if a drain obstruction has taken place. If
the drain 115 or plumbing is plugged on the suction side of the
pump 140, the pressure on that side of the pump 140 increases. At
the same time, because the pump 140 is no longer pumping water,
input power to the motor 145 drops. If either of these conditions
occur, the controller 150 declares a fault, the motor 145 powers
down, and a fault indicator lights.
[0032] A voltage sense and average circuit 165, a current sense and
average circuit 170, a line voltage sense circuit 175, a triac
voltage sense circuit 180, and the microcontroller 185 perform the
monitoring of the input power. One example voltage sense and
average circuit 165 is shown in FIG. 3A. The voltage sense and
average circuit 165 includes resistors R34, R41, and R42; diode D9;
capacitor C10; and operational amplifier U4A. The voltage sense and
average circuit 165 rectifies the voltage from the power source 155
and then performs a DC average of the rectified voltage. The DC
average is then fed to the microcontroller 185.
[0033] One example current sense and average circuit 170 is shown
in FIG. 3A. The current sense and average circuit 170 includes
transformer T1 and resistor R45, which act as a current sensor that
senses the current applied to the motor. The current sense and
average circuit also includes resistors R25, R26, R27, R28, and
R33; diodes D7 and D8; capacitor C9; and operational amplifiers U4C
and U4D, which rectify and average the value representing the
sensed current. For example, the resultant scaling of the current
sense and average circuit 170 can be a negative five to zero volt
value corresponding to a zero to twenty-five amp RMS value. The
resulting DC average is then fed to the microcontroller 185.
[0034] One example line voltage sense circuit 175 is shown in FIG.
3A. The line voltage sense circuit 175 includes resistors R23, R24,
and R32; diode D5; zener diode D6; transistor Q6; and NAND gate
U2B. The line voltage sense circuit 175 includes a zero-crossing
detector that generates a pulse signal. The pulse signal includes
pulses that are generated each time the line voltage crosses zero
volts.
[0035] One example triac voltage sense circuit 180 is shown in FIG.
3A. The triac voltage sense circuit 180 includes resistors R1, R5,
and R6; diode D2; zener diode D1; transistor Q1; and NAND gate U2A.
The triac voltage sense circuit includes a zero-crossing detector
that generates a pulse signal. The pulse signal includes pulses
that are generated each time the motor current crosses zero.
[0036] One example microcontroller 185 that can be used with the
invention is a Motorola brand microcontroller, model no.
MC68HC908QY4CP. The microcontroller 185 includes a processor and a
memory. The memory includes software instructions that are read,
interpreted, and executed by the processor to manipulate data or
signals. The memory also includes data storage memory. The
microcontroller 185 can include other circuitry (e.g., an
analog-to-digital converter) necessary for operating the
microcontroller 185. In general, the microcontroller 185 receives
inputs (signals or data), executes software instructions to analyze
the inputs, and generates outputs (signals or data) based on the
analyses. Although the microcontroller 185 is shown and described,
the functions of the microcontroller 185 can be implemented with
other devices, including a variety of integrated circuits (e.g., an
application-specific-integrated circuit), programmable devices,
and/or discrete devices, as would be apparent to one of ordinary
skill in the art. Additionally, it is envisioned that the
microcontroller 185 or similar circuitry can be distributed among
multiple microcontrollers 185 or similar circuitry. It is also
envisioned that the microcontroller 185 or similar circuitry can
perform the function of some of the other circuitry described
(e.g., circuitry 165-180) above for the controller 150. For
example, the microcontroller 185, in some constructions, can
receive a sensed voltage and/or sensed current and determine an
averaged voltage, an averaged current, the zero-crossings of the
sensed voltage, and/or the zero crossings of the sensed
current.
[0037] The microcontroller 185 receives the signals representing
the average voltage applied to the motor 145, the average current
through the motor 145, the zero crossings of the motor voltage, and
the zero crossings of the motor current. Based on the zero
crossings, the microcontroller 185 can determine a power factor.
The power factor can be calculated using known mathematical
equations or by using a lookup table based on the mathematical
equations. The microcontroller 185 can then calculate a power with
the averaged voltage, the averaged current, and the power factor as
is known. As will be discussed later, the microcontroller 185
compares the calculated power with a power calibration value to
determine whether a fault condition (e.g., due to an obstruction)
is present.
[0038] Referring again to FIGS. 2 and 3A, a pressure (or vacuum)
sensor circuit 190 and the microcontroller 185 monitor the pump
inlet side pressure. One example pressure sensor circuit 190 is
shown in FIG. 3A. The pressure sensor circuit 190 includes
resistors R16, R43, R44, R47, and R48; capacitors C8, C12, C15, and
C17; zener diode D4, piezoresistive sensor U9, and operational
amplifier U4-B. The piezoresistive sensor U9 is plumbed into the
suction side of the pump 140. The pressure sensor circuit 190 and
microcontroller 185 translate and amplify the signal generated by
the piezoresistive sensor U9 into a value representing inlet
pressure. As will be discussed later, the microcontroller 185
compares the resulting pressure value with a pressure calibration
value to determine whether a fault condition (e.g., due to an
obstruction) is present.
[0039] The calibrating of the controller 150 occurs when the user
activates a calibrate switch 195. One example calibrate switch 195
is shown in FIG. 3A. The calibrate switch 195 includes resistor R18
and Hall effect switch U1. When a magnet passes Hall effect switch
U10, the switch 195 generates a signal provided to the
microcontroller 185. Upon receiving the signal, the microcontroller
185 stores a pressure calibration value for the pressure sensor by
acquiring the current pressure and stores a power calibration value
for the motor by calculating the present power.
[0040] As stated earlier, the controller 150 controllably provides
power to the motor 145. With references to FIG. 2 and 3A, the
controller 150 includes a retriggerable pulse generator circuit
200. The retriggerable pulse generator circuit 200 includes
resistor R7, capacitor C1, and pulse generator U1A, and outputs a
value to NAND gate U2D if the retriggerable pulse generator circuit
200 receives a signal having a pulse frequency greater than a set
frequency determined by resistor R7 and capacitor C1. The NAND gate
U2D also receives a signal from power-up delay circuit 205, which
prevents nuisance triggering of the relay on startup. The output of
the NAND gate U2D is provided to relay driver circuit 210. The
relay driver circuit 210 shown in FIG. 3A includes resistors R19,
R20, R21, and R22; capacitor C7; diode D3; and switches Q5 and Q4.
The relay driver circuit 210 controls relay K1.
[0041] The microcontroller 185 also provides an output to triac
driver circuit 215, which controls triac Q2. As shown in FIG. 3A,
the triac driver circuit 215 includes resistors R12, R13, and R14;
capacitor C11; and switch Q3. In order for current to flow to the
motor, relay K1 needs to close and triac Q2 needs to be triggered
on.
[0042] The controller 150 also includes a thermoswitch S1 for
monitoring the triac heat sink, a power supply monitor 220 for
monitoring the voltages produced by the power supply 160, and a
plurality of LEDs DS1, DS2, and DS3 for providing information to
the user. In the construction shown, a green LED DS1 indicates
power is applied to the controller 150, a red LED DS2 indicates a
fault has occurred, and a third LED DS3 is a heartbeat LED to
indicate the microcontroller 185 is functioning. Of course, other
interfaces can be used for providing information to the
operator.
[0043] The following describes the normal sequence of events for
one method of operation of the controller 150. When the fluid
movement system 110 is initially activated, the system 110 may have
to draw air out of the suction side plumbing and get the fluid
flowing smoothly. This "priming" period usually lasts only a few
seconds, but could last a minute or more if there is a lot of air
in the system. After priming, the water flow, suction side
pressure, and motor input power remain relatively constant. It is
during this normal running period that the circuit is effective at
detecting an abnormal event. The microcontroller 185 includes a
startup-lockout feature that keeps the monitor from detecting the
abnormal conditions during the priming period.
[0044] After the system 110 is running smoothly, the spa operator
can calibrate the controller 150 to the current spa running
conditions. The calibration values are stored in the
microcontroller 185 memory, and will be used as the basis for
monitoring the spa 100. If for some reason the operating conditions
of the spa change, the controller 150 can be re-calibrated by the
operator. If at any time during normal operations, however, the
suction side pressure increases substantially (e.g., 12%) over the
pressure calibration value, or the motor input power drops (e.g.,
12%) under the power calibration value, the pump will be powered
down and a fault indicator is lit.
[0045] As discussed earlier, the controller 150 measures motor
input power, and not just motor power factor or input current. Some
motors have electrical characteristics such that power factor
remains constant while the motor is unloaded. Other motors have an
electrical characteristic such that current remains relatively
constant when the pump is unloaded. However, the input power drops
on pump systems when the drain is plugged, and water flow is
impeded.
[0046] The voltage sense and average circuit 165 generates a value
representing the average power line voltage and the current sense
and average circuit 170 generates a value representing the average
motor current. Motor power factor is derived from the difference
between power line zero crossing events and triac zero crossing
events. The line voltage sense circuit 175 provides a signal
representing the power line zero crossings. The triac zero
crossings occur at the zero crossings of the motor current. The
triac voltage sense circuit 180 provides a signal representing the
triac zero crossings. The time difference from the zero crossing
events is used to look up the motor power factor from a table
stored in the microcontroller 185. This data is then used to
calculate the motor input power using equation e1.
V.sub.avg*I.sub.avg*PF=Motor_Input_Power [e1]
[0047] The calculated motor_input_power is then compared to the
calibrated value to determine whether a fault has occurred. If a
fault has occurred, the motor is powered down and the fault LED DS2
is lit.
[0048] FIG. 4 is a block diagram of a second construction of the
controller 150a, and FIGS. 5A and 5B are an electrical schematic of
the controller 150a. As shown in FIG. 4, the controller 150a is
electrically connected to a power source 155 and the motor 145.
[0049] With reference to FIG. 4 and FIG. 5B, the controller 150a
includes a power supply 160a. The power supply 160a includes
resistors R54, R56 and R76; capacitors C16, C18, C20, C21, C22, C23
and C25; diodes D8, D10 and D11; zener diodes D6, D7 and D9; power
supply controller U11; regulator U9; inductors L1 and L2, surge
suppressors MOV1 and MOV2, and optical switch U10. The power supply
160a receives power from the power source 155 and provides the
proper DC voltage (e.g., +5 VDC and +12 VDC) for operating the
controller 150a.
[0050] For the controller 150a shown in FIG. 4, FIG. 5A, and FIG.
5B, the controller 150a monitors motor input power to determine if
a drain obstruction has taken place. Similar to the earlier
disclosed construction, if the drain 115 or plumbing is plugged on
the suction side of the pump 140, the pump 140 will no longer be
pumping water, and input power to the motor 145 drops. If this
condition occurs, the controller 150a declares a fault, the motor
145 powers down, and a fault indicator lights.
[0051] A voltage sense and average circuit 165a, a current sense
and average circuit 170a, and the microcontroller 185a perform the
monitoring of the input power. One example voltage sense and
average circuit 165a is shown in FIG. 5A. The voltage sense and
average circuit 165a includes resistors R2, R31, R34, R35, R39,
R59, R62, and R63; diodes D2 and D12; capacitor C14; and
operational amplifiers U5C and U5D. The voltage sense and average
circuit 165a rectifies the voltage from the power source 155 and
then performs a DC average of the rectified voltage. The DC average
is then fed to the microcontroller 185a. The voltage sense and
average circuit 165a further includes resistors R22, R23, R27, R28,
R30, and R36; capacitor C27; and comparator U7A; which provide the
sign of the voltage waveform (i.e., acts as a zero-crossing
detector) to the microcontroller 185a.
[0052] One example current sense and average circuit 170a is shown
in FIG. 5B. The current sense and average circuit 170a includes
transformer T1 and resistor R53, which act as a current sensor that
senses the current applied to the motor 145. The current sense and
average circuit 170a also includes resistors R18, R20, R21, R40,
R43, and R57; diodes D3 and D4; capacitor C8; and operational
amplifiers U5A and U5B, which rectify and average the value
representing the sensed current. For example, the resultant scaling
of the current sense and average circuit 170a can be a positive
five to zero volt value corresponding to a zero to twenty-five amp
RMS value. The resulting DC average is then fed to the
microcontroller 185a. The current sense and average circuit 170a
further includes resistors R24, R25, R26, R29, R41, and R44;
capacitor C11; and comparator U7B; which provide the sign of the
current waveform (i.e., acts as a zero-crossing detector) to
microcontroller 185a.
[0053] One example microcontroller 185a that can be used with the
invention is a Motorola brand microcontroller, model no.
MC68HC908QY4CP. Similar to what was discussed for the earlier
construction, the microcontroller 185a includes a processor and a
memory. The memory includes software instructions that are read,
interpreted, and executed by the processor to manipulate data or
signals. The memory also includes data storage memory. The
microcontroller 185a can include other circuitry (e.g., an
analog-to-digital converter) necessary for operating the
microcontroller 185a and/or can perform the function of some of the
other circuitry described above for the controller 150a. In
general, the microcontroller 185a receives inputs (signals or
data), executes software instructions to analyze the inputs, and
generates outputs (signals or data) based on the analyses.
[0054] The microcontroller 185a receives the signals representing
the average voltage applied to the motor 145, the average current
through the motor 145, the zero crossings of the motor voltage, and
the zero crossings of the motor current. Based on the zero
crossings, the microcontroller 185a can determine a power factor
and a power as was described earlier. The microcontroller 185a can
then compare the calculated power with a power calibration value to
determine whether a fault condition (e.g., due to an obstruction)
is present.
[0055] The calibrating of the controller 150a occurs when the user
activates a calibrate switch 195a. One example calibrate switch
195a is shown in FIG. 5A, which is similar to the calibrate switch
195 shown in FIG. 3A. Of course, other calibrate switches are
possible. In one method of operation for the calibrate switch 195a,
a calibration fob needs to be held near the switch 195a when the
controller 150a receives an initial power. After removing the
magnet and cycling power, the controller 150a goes through priming
and enters an automatic calibration mode (discussed below).
[0056] The controller 150a controllably provides power to the motor
145. With references to FIG. 4 and 5A, the controller 150a includes
a retriggerable pulse generator circuit 200a. The retriggerable
pulse generator circuit 200a includes resistors R15 and R16,
capacitors C2 and C6, and pulse generators U3A and U3B, and outputs
a value to the relay driver circuit 210a if the retriggerable pulse
generator circuit 200a receives a signal having a pulse frequency
greater than a set frequency determined by resistors R15 and R16,
and capacitors C2 and C6. The retriggerable pulse generators U3A
and U3B also receive a signal from power-up delay circuit 205a,
which prevents nuisance triggering of the relays on startup. The
relay driver circuits 210a shown in FIG. 5A include resistors R1,
R3, R47, and R52; diodes D1 and D5; and switches Q1 and Q2. The
relay driver circuits 210a control relays K1 and K2. In order for
current to flow to the motor, both relays K1 and K2 need to
"close".
[0057] The controller 150a further includes two voltage detectors
212a and 214a. The first voltage detector 212a includes resistors
R71, R72, and R73; capacitor C26; diode D14; and switch Q4. The
first voltage detector 212a detects when voltage is present across
relay K1, and verifies that the relays are functioning properly
before allowing the motor to be energized. The second voltage
detector 214a includes resistors R66, R69, and R70; capacitor C9;
diode D13; and switch Q3. The second voltage detector 214a senses
if a two speed motor is being operated in high or low speed mode.
The motor input power trip values are set according to what speed
the motor is being operated. It is also envisioned that the
controller 150a can be used with a single speed motor without the
second voltage detector 214a (e.g., controller 150b is shown in
FIG. 6).
[0058] The controller 150a also includes an ambient thermal sensor
circuit 216a for monitoring the operating temperature of the
controller 150a, a power supply monitor 220a for monitoring the
voltages produced by the power supply 160a, and a plurality of LEDs
DS1 and DS3 for providing information to the user. In the
construction shown, a green LED DS2 indicates power is applied to
the controller 150a, and a red LED DS3 indicates a fault has
occurred. Of course, other interfaces can be used for providing
information to the operator.
[0059] The controller 150a further includes a clean mode switch
218a, which includes switch U4 and resistor R10. The clean mode
switch can be actuated by an operator (e.g., a maintenance person)
to deactivate the power monitoring function described herein for a
time period (e.g., 30 minutes so that maintenance person can clean
the vessel 105). Moreover, the red LED DS3 can be used to indicate
that controller 150a is in a clean mode. After the time period, the
controller 150a returns to normal operation. In some constructions,
the maintenance person can actuate the clean mode switch 218a for
the controller 150a to exit the clean mode before the time period
is completed.
[0060] In some cases, it may be desirable to deactivate the power
monitoring function for reasons other than performing cleaning
operations on the vessel 105. Such cases may be referred as
"deactivate mode", "disabled mode", "unprotected mode", or the
like. Regardless of the name, this later mode of operation can be
at least partially characterized by the instructions defined under
the clean mode operation above. Moreover, when referring to the
clean mode and its operation herein, the discussion also applies to
these later modes for deactivating the power monitoring function
and vice versa.
[0061] The following describes the normal sequence of events for
one method of operation of the controller 150a, some of which may
be similar to the method of operation of the controller 150. When
the fluid movement system 110 is initially activated, the system
110 may have to prime (discussed above) the suction side plumbing
and get the fluid flowing smoothly (referred to as "the normal
running period"). It is during the normal running period that the
circuit is most effective at detecting an abnormal event.
[0062] Upon a system power-up, the system 110 can enter a priming
period. The priming period can be preset for a time duration (e.g.,
a time duration of 3 minutes), or for a time duration determined by
a sensed condition. After the priming period, the system 110 enters
the normal running period. The controller 150a can include
instructions to perform an automatic calibration to determine one
or more calibration values after a first system power-up. One
example calibration value is a power calibration value. In some
cases, the power calibration value is an average of monitored power
values over a predetermined period of time. The power calibration
value is stored in the memory of the microcontroller 185, and will
be used as the basis for monitoring the vessel 105.
[0063] If for some reason the operating conditions of the vessel
105 change, the controller 150a can be re-calibrated by the
operator. In some constructions, the operator actuates the
calibrate switch 195a to erase the existing one or more calibration
values stored in the memory of the microcontroller 185. The
operator then powers down the system 110, particularly the motor
145, and performs a system power-up. The system 110 starts the
automatic calibration process as discussed above to determine new
one or more calibration values. If at any time during normal
operation, the monitored power varies from the power calibration
value (e.g., varies from a 12.5% window around the power
calibration value), the motor 145 will be powered down and the
fault LED DS3 is lit.
[0064] In one construction, the automatic calibration instructions
include not monitoring the power of the motor 145 during a start-up
period, generally preset for a time duration (e.g., 2 seconds),
upon the system power-up. In the case when the system 110 is
operated for the first time, the system 110 enters the prime
period, upon completion of the start-up period, and the power of
the motor 145 is monitored to determine the power calibration
value. As indicated above, the power calibration value is stored in
the memory of the microcontroller 185. After completion of the 3
minutes of the priming period, the system 110 enters the normal
running period. In subsequent system power-ups, the monitored power
is compared against the power calibration value stored in the
memory of the microcontroller 185 memory during the priming period.
More specifically, the system 110 enters the normal running period
when the monitored power rises above the power calibration value
during the priming period. In some cases, the monitored power does
not rise above the power calibration value within the 3 minutes of
the priming period. As a consequence, the motor 145 is powered down
and a fault indicator is lit.
[0065] In other constructions, the priming period of the automatic
calibration can include a longer preset time duration (for example,
4 minutes) or an adjustable time duration capability. Additionally,
the controller 150a can include instructions to perform signal
conditioning operations to the monitored power. For example, the
controller 150a can include instructions to perform an IIR filter
to condition the monitored power. In some cases, the IIR filter can
be applied to the monitored power during the priming period and the
normal operation period. In other cases, the IIR filter can be
applied to the monitored power upon determining the power
calibration value after the priming period.
[0066] Similar to controller 150, the controller 150a measures
motor input power, and not just motor power factor or input
current. However, it is envisioned that the controllers 150 or 150a
can be modified to monitor other motor parameters (e.g., only motor
current, only motor power factor, or motor speed). But motor input
power is the preferred motor parameter for controller 150a for
determining whether the water is impeded. Also, it is envisioned
that the controller 150a can be modified to monitor other
parameters (e.g., suction side pressure) of the system 110.
[0067] For some constructions of the controller 150a, the
microcontroller 185a monitors the motor input power for an over
power condition in addition to an under power condition. The
monitoring of an over power condition helps reduce the chance that
controller 150a was incorrectly calibrated, and/or also helps
detect when the pump is over loaded (e.g., the pump is moving too
much fluid).
[0068] The voltage sense and average circuit 165a generates a value
representing the averaged power line voltage and the current sense
and average circuit 170a generates a value representing the
averaged motor current. Motor power factor is derived from the
timing difference between the sign of the voltage signal and the
sign of the current signal. This time difference is used to look up
the motor power factor from a table stored in the microcontroller
185a. The averaged power line voltage, the averaged motor current,
and the motor power factor are then used to calculate the motor
input power using equation e1 as was discussed earlier. The
calculated motor input power is then compared to the calibrated
value to determine whether a fault has occurred. If a fault has
occurred, the motor is powered down and the fault indicator is
lit.
[0069] Redundancy is also used for the power switches of the
controller 150a. Two relays K1 and K2 are used in series to do this
function. This way, a failure of either component will still leave
one switch to turn off the motor 145. As an additional safety
feature, the proper operation of both relays is checked by the
microcontroller 185a every time the motor 145 is powered-on via the
relay voltage detector circuit 212a.
[0070] Another aspect of the controller 150a is that the
microcontroller 185a provides pulses at a frequency greater than a
set frequency (determined by the retriggerable pulse generator
circuits) to close the relays K1 and K2. If the pulse generators
U3A and U3B are not triggered at the proper frequency, the relays
K1 and K2 open and the motor powers down.
[0071] As previously indicated, the microcontroller 185, 185a can
calculate an input power based on parameters such as averaged
voltage, averaged current, and power factor. The microcontroller
185, 185a then compares the calculated input power with the power
calibration value to determine whether a fault condition (e.g., due
to an obstruction) is present. Other constructions can include
variations of the microcontroller 185, 185a and the controller 150,
150a operable to receive other parameters and determine whether a
fault condition is present.
[0072] One aspect of the controller 150, 150a is that the
microcontroller 185, 185a can monitor the change of input power
over a predetermine period of time. More specifically, the
microcontroller 185, 185a determines and monitors a power
derivative value equating about a change in input power divided by
a change in time. In cases where the power derivative traverses a
threshold value, the controller 150, 150a controls the motor 145 to
shut down the pump 140. This aspect of the controller 150, 150a may
be operable in replacement of, or in conjunction with, other
similar aspects of the controller 150, 150a, such as shutting down
the motor 145 when the power level of the motor 145 traverses a
predetermined value.
[0073] For example, FIG. 7 shows a graph indicating input power and
power derivative as functions of time. More specifically, FIG. 7
shows a power reading (line 300) and a power derivate value (line
305), over a 30-second time period, of a motor 145 calibrated at a
power threshold value of 5000 and a power derivative threshold of
-100. In this particular example, a water blockage in the
fluid-movement system 110 (shown in FIG. 1) occurs at the 20-second
mark. It can be observed from FIG. 7 that the power reading 300
indicates a power level drop below the threshold value of 5000 at
the 27-second mark, causing the controller 150, 150a to shut down
the pump 140 approximately at the 28-second mark. It can also be
observed that the power derivative value 305 drops below the -100
threshold value at the 22-second mark, causing the controller 150,
150a to shut down the pump 140 approximately at the 23-second mark.
Other parameters of the motor 145 (e.g., torque) can be monitored
by the microcontroller 185, 185a, for determining a potential
entrapment event.
[0074] In another aspect of the controller 150, 150a, the
microcontroller 185, 185a can include instructions that correspond
to a model observer, such as the exemplary model observer 310 shown
in FIG. 8. The model observer 310 includes a first filter 315, a
regulator 325 having a variable gain 326 and a transfer function
327, a fluid system model 330 having a gain parameter (shown in
FIG. 8 with the value of 1), and a second filter 335. In
particular, the fluid system model 330 is configured to simulate
the fluid-movement system 110. Additionally, the first filter 315
and the second filter 335 can include various types of analog and
digital filters such as, but not limited to, low pass, high pass,
band pass, anti-aliasing, IIR, and/or FIR filters.
[0075] It is to be understood that the model observer 310 is not
limited to the elements described above. In other words, the model
observer 310 may not necessarily include all the elements described
above and/or may include other elements or combination of elements
not explicitly described herein. In reference particularly to the
fluid system model 330, a fluid system model may be defined
utilizing various procedures. In some cases, a model may be
generated for this particular aspect of the controller 150, 150a
from another model corresponding to a simulation of another system,
which may not necessarily be a fluid system. In other cases, a
model may be generated solely based on controls knowledge of closed
loop or feed back systems and formulas for fluid flow and power. In
yet other cases, a model may be generated by experimentation with a
prototype of the fluid system to be modeled.
[0076] In reference to the model observer 310 of FIG. 8, the first
filter 315 receives a signal (P) corresponding to a parameter of
the motor 145 determined and monitored by the microcontroller 185,
185a (e.g., input power, torque, current, power factor, etc.).
Generally, the first filter 315 is configured to substantially
eliminate the noise in the received signal (P), thus generating a
filtered signal (PA). However, the first filter 315 may perform
other functions such as anti-aliasing or filtering the received
signal to a predetermined frequency range. The filtered signal (PA)
enters a feed-back loop 340 of the model observer 310 and is
processed by the regulator 325. The regulator 325 outputs a
regulated signal (ro) related to the fluid flow and/or pressure
through the fluid-movement system 110 based on the monitored
parameter. The regulated signal can be interpreted as a modeled
flow rate or modeled pressure. The fluid system model 330 processes
the regulated signal (ro) to generate a model signal (Fil), which
is compared to the filtered signal (PA) through the feed-back loop
340. The regulated signal (ro) is also fed to the second filter 335
generating a control signal (roP), which is subsequently used by
the microcontroller 185, 185a to at least control the operation of
the motor 145.
[0077] As shown in FIG. 8, the regulated signal (ro), indicative of
fluid flow and/or pressure, is related to the monitored parameter
as shown in equation [e2].
ro=(PA-Fil)*regulator [e2]
The relationship shown in equation [e2] allows a user to control
the motor 145 based on a direct relationship between the input
power or torque and a parameter of the fluid flow, such as flow
rate and pressure, without having to directly measure the fluid
flow parameter.
[0078] FIG. 9 is a graph showing an input power (line 345) and a
processed power or flow unit (line 350) as functions of time. More
specifically, the graph of FIG. 9 illustrates the operation of the
fluid-movement system 110 with the motor 145 having a threshold
value of 5000. For this particular example, FIG. 9 shows that the
pump inlet 125 blocked at the 5-second mark. The input power drops
below the threshold mark of 5000, and therefore the controller 150,
150a shuts down the pump 140 approximately at the 12.5-second mark.
Alternatively, the processed power signal drops below the threshold
mark corresponding to 5000 at the 6-second mark, and therefore the
controller 150, 150a shuts down the pump 140 approximately at the
7-second mark.
[0079] In this particular example, the gain parameter of the fluid
system model 330 is set to a value of 1, thereby measuring a unit
of pressure with the same scale as the unit of power. In other
examples, the user can set the gain parameter at a different value
to at least control aspects of the operation of the motor 145, such
as shut down time.
[0080] In another aspect of the controller 150, 150a, the
microcontroller 185, 185a can be configured for determining a
floating the threshold value or trip value indicating the parameter
reading, such as input power or torque, at which the controller
150, 150a shuts down the pump 140. It is to be understood that the
term "floating" refers to varying or adjusting a signal or value.
In one example, the microcontroller 185, 185a continuously adjusts
the trip value based on average input power readings, as shown in
FIG. 10. More specifically, FIG. 10 shows a graph indicating an
average input power signal (line 355) determined and monitored by
the microcontroller 185, 185a, a trip signal (line 360) indicating
a variable trip value, and a threshold value of about 4500 (shown
in FIG. 10 with arrow 362) as a function of time. In this
particular case, the threshold value 362 is a parameter indicating
the minimum value that the trip value can be adjusted to.
[0081] The microcontroller 185, 185a may calculate the average
input power 355 utilizing various methods. In one construction, the
microcontroller 185, 185a may determine a running average based at
least on signals generated by the current sense and average circuit
170, 170a and signals generated by the voltage sense and average
circuit 165, 165a. In another construction, the microcontroller
185, 185a may determine an input power average over relatively
short periods of time. As shown in FIG. 10, the average power
determined by the microcontroller 185, 185a goes down from about
6000 to about 5000 in a substantially progressive manner over a
time period of 80 units of time. It can also be observed that the
signal 360 indicating the trip value is adjusted down to about 10%
from the value at the 0-time unit mark to the 80-time unit mark and
is substantially parallel to the average power 355. More
specifically, the microcontroller 185, 185a adjusts the trip value
based on monitoring the average input power 355.
[0082] In some cases, the average power signal 355 may define a
behavior, such as the one shown in FIG. 10, due to sustained
clogging of the fluid-movement system 110 over a period of time,
for example from the 0-time unit mark to the 80-time unit mark. In
other words, sustained clogging of the fluid-movement system 110
can be determined and monitored by the microcontroller 185, 185a in
the form of the average power signal 355. In these cases, the
microcontroller 185, 185a can also determine a percentage or value
indicative of a minimum average input power allowed to be supplied
to the motor 145, or a minimum allowed threshold value such as
threshold value 362. When the fluid-movement system 110 is
back-flushed with the purpose of unclogging the fluid-movement
system 110, the average power signal 355 returns to normal
unrestricted fluid flow (shown in FIG. 10 between about the 84-time
unit mark and about the 92-time unit mark, for example). As shown
in FIG. 10, unclogging the fluid-movement system 110 can result in
relative desired fluid flow through the fluid-movement system 110.
As a consequence, the microcontroller 185, 185a senses an average
power change as indicated near the 80-time unit mark in FIG. 10
showing as the average power returns to the calibration value.
[0083] In other cases, the microcontroller 185, 185a can determine
and monitor the average input power over a relatively short amount
of time. For example, the microcontroller 185, 185a can monitor the
average power over a first time period (e.g., 5 seconds). The
controller 185, 185a can also determine a variable trip value based
on a predetermine percentage (e.g., 6.25%) drop of the average
power calculated over the first time period. In other words, the
variable trip value is adjusted based on the predetermined
percentage as the microcontroller 185, 185a determines the average
power. The controller 150, 150a can shut down the pump 140 when the
average power drops to a value substantially equal or lower than
the variable trip value and sustains this condition over a second
period of time (e.g., 1 second).
[0084] In another aspect of the controller 150, 150a, the
microcontroller 185, 185a can be configured to determine a
relationship between a parameter of the motor 145 (such as power or
torque) and pressure/flow through the fluid-movement system 110 for
a specific motor/pump combination. More specifically, the
controller 150, 150a controls the motor 145 to calibrate the
fluid-movement system 110 based on the environment in which the
fluid-movement system 110 operates. The environment in which the
fluid-movement system 110 operates can be defined by the capacity
of the vessel 105, tubing configuration between the drain 115 and
inlet 125, tubing configuration between outlet 130 and return 135
(shown in FIG. 1), number of drains and returns, and other factors
not explicitly discussed herein.
[0085] Calibration of the fluid-movement system 110 is generally
performed the first time the system is operated after installation.
It is to be understood that the processes described herein are also
applicable to recalibration procedures. In one example, calibration
of the fluid-movement system 110 includes determining a threshold
value based on characterizing a specific motor/pump combination and
establishing a relationship between, for example, input power and
pressure via a stored look-up table or an equation. FIG. 11 shows a
chart having characterization data (line 365), measured in
kilowatts and obtained through a calibration process, and a pump
curve (line 370) indicating head pressure. The characterization
data 365 and the pump curve 370 are graphed as a function of flow
measured in gallons per minute (GPM). In the particular example
shown in FIG. 11, it is possible for a user (or the microcontroller
185, 185a in an automated process) to establish a trip value based
on a percent reduction in flow or pressure instead of a percent
reduction in input power.
[0086] Referring particularly to the characterization data 365
shown in FIG. 11, if an operating point for the fluid-movement
system 110 is determined at point 1 on the characterization data
365, a 30% reduction in flow from 100 GPM to 70 GPM (point 2 on the
characterization data 365) through the fluid-movement system 110 is
monitored by the microcontroller 185, 185a and indicates a 7%
reduction in input power. For a different environment of the
fluid-movement system 110, the operating set point can be
established at point 2, for example. Particularly, a 30% reduction
in flow from 70 GPM to 50 GPM (point 3 on the characterization data
365) through the fluid-movement system 110 is monitored by the
microcontroller 185, 185a and indicates an 11% reduction in power.
For the two cases described above, it is possible that a 30%
reduction in flow is a desired operating condition, thus a user (or
microcontroller 185, 185a) can establish a trip value or percentage
based on the percent reduction (e.g., a reduction of 30% in flow)
separate from the determined and monitored power.
[0087] In another aspect of the controller 150, 150a, the
microcontroller 185, 185a can include a timer function to operate
the fluid-movement system 110. In one example, the timer function
of the microcontroller 185, 185a implements a RUN mode of the
controller 150, 150a. More specifically regarding the RUN mode, the
controller 150, 150a is configured to operate the motor 145
automatically over predetermined periods of time. In other words,
the controller 150, 150a is configured to control the motor 145
based on predetermined time periods programmed in the
microcontroller 185, 185a during manufacturing or programmed by a
user. In another example, the timer function of the microcontroller
185, 185a implements an OFF mode of the controller 150, 150a. More
specifically regarding the OFF mode, the controller 150, 150a is
configured to operate the motor 145 only as a result of direct
interaction of the user. In other words, the controller 150, 150a
is configured to maintain the motor 145 off until a user directly
operates the controller 150, 150a through the interface of the
controller 150, 150a. In yet another example, the timer function of
the microcontroller 185, 185a implements a PROGRAM mode of the
controller 150, 150a. More specifically regarding the PROGRAM mode,
the controller 150, 150a is configured to maintain the motor 145
off until the user actuates one of the switches (e.g., calibrate
switch 195, 195a, clean mode switch 218a) of the controller 150,
150a indicating a desired one-time window of operation of the motor
145. For example, the user can actuate one switch three times
indicating the controller 150, 150a to operate the motor 145 for a
period of three hours. In some constructions, the controller 150,
150a includes a run-off-program switch to operate the controller
150, 150a between the RUN, OFF, and PROGRAM modes. It is to be
understood that the same or other modes of operation of the
controller 150, 150a can be defined differently. Additionally, not
all modes described above are necessary and the controller 150,
150a can include a different number and combinations of modes of
operation.
[0088] In another aspect of the controller 150, 150a, the
microcontroller 185, 185a can be configured to determine and
monitor a value corresponding to the torque of the motor 145. More
specifically, the microcontroller 185, 185a receives signals from
at least one of the voltage sense and average circuit 165, 165a and
the current sense and average circuit 170, 170a to help determine
the torque of the motor 145. As explained above, the
microcontroller 185, 185a can also be configured to determine and
monitor the speed of the motor 145, allowing the microcontroller
185, 185a to determine a value indicative of the torque of the
motor 145 and a relationship between the torque and the input
power. In some constructions, the speed of the motor 145 remains
substantially constant during operation of the motor 145. In these
particular cases, the microcontroller 185, 185a can include
instructions related to formulas or look-up tables that indicate a
direct relationship between the input power and the torque of the
motor 145. Determining and monitoring the torque of the motor 145
allows the microcontroller 185, 185a to establish a trip value or a
percentage based on torque to shut off the motor 145 in case of an
undesired condition of the motor 145. For example, FIG. 12 shows a
chart indicating a relationship between input power and torque for
a motor 145 under the observation that the speed of the motor 145
changes less than 2%. Thus, the microcontroller 185, 185a can
determine and monitor torque based on input power and under the
assumption of constant speed.
[0089] In some constructions, the fluid-movement system 110 can
operate two or more vessels 105. For example, the fluid-movement
system 110 can include a piping system to control fluid flow to a
pool, and a second piping system to control fluid flow to a spa.
For this particular example, the flow requirements for the pool and
the spa are generally different and may define or require separate
settings of the controller 150, 150a for the controller 150, 150a
to operate the motor 145 to control fluid flow to the pool, the
spa, or both. The fluid-movement system 110 can include one or more
valves that may be manually or automatically operated to direct
fluid flow as desired. In an exemplary case where the
fluid-movement system 110 includes one solenoid valve, a user can
operate the valve to direct flow to one of the pool and the spa.
Additionally, the controller 150, 150a can include a sensor or
receiver coupled to the valve to determine the position of the
valve. Under the above mentioned conditions, the controller 150,
150a can run a calibration sequence and determine individual
settings and trip values for the fluid system including the pool,
the spa, or both. Other constructions can include a different
number of vessels 105, where fluid flow to the number of vessels
105 can be controller by one or more fluid-movement systems
110.
[0090] While numerous aspects of the controller 150, 150a were
discussed above, not all of the aspects and features discussed
above are required for the invention. Additionally, other aspects
and features can be added to the controller 150, 150a shown in the
figures.
[0091] The constructions described above and illustrated in the
figures are presented by way of example only and are not intended
as a limitation upon the concepts and principles of the invention.
Various features and advantages of the invention are set forth in
the following claims.
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