U.S. patent number 3,697,821 [Application Number 05/167,712] was granted by the patent office on 1972-10-10 for light dimming system having multiple control units.
This patent grant is currently assigned to Hunt Electronics Company. Invention is credited to James C. Johnson.
United States Patent |
3,697,821 |
Johnson |
October 10, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
LIGHT DIMMING SYSTEM HAVING MULTIPLE CONTROL UNITS
Abstract
A plurality of separate remote control units are provided for
individually and independently controlling the operation of a
common lamp dimmer unit. Each remote control unit is capable of
turning on and off the lamp dimmer unit and of controlling the
brightness of the lamp or lamps independently of the previous
setting or condition of any of the other remote control units. The
various remote control units are connected in parallel with one
another and with the remainder of the system by a three-wire
conductor system.
Inventors: |
Johnson; James C. (Arlington,
TX) |
Assignee: |
Hunt Electronics Company
(Dallas, TX)
|
Family
ID: |
22608502 |
Appl.
No.: |
05/167,712 |
Filed: |
July 30, 1971 |
Current U.S.
Class: |
361/205;
340/13.37; 307/115; 307/112; 315/194 |
Current CPC
Class: |
H05B
47/10 (20200101) |
Current International
Class: |
H05B
37/02 (20060101); H01h 047/32 () |
Field of
Search: |
;317/136,146,148.5,149,154,157 ;323/24 ;340/147R,150
;315/194,199,200,208,DIG.4 ;307/112,113,114,139,140,157 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Miller; J. D.
Assistant Examiner: Moose, Jr.; Harry E.
Claims
What is claimed is:
1. A light dimming system comprising:
dimmer circuit means for controlling the current flow through a
lamp load;
and a plurality of separate control units coupled to the dimmer
circuit means and each including means for selectively activating
and disabling the dimmer circuit means and adjustable means for
modifying the control action of the dimmer circuit means.
2. A light dimming system in accordance with claim 1 wherein the
adjustable means in each control unit is a variable resistor.
3. A light dimming system in accordance with claim 1 wherein the
various control unit are connected in parallel with one another by
conductor means having only three wires.
4. A light dimming system in accordance with claim 1 wherein each
control unit includes means for automatically disabling the other
control units when the activating means in anr one of the control
units is operated.
5. A light dimming system comprising:
dimmer circuit means having a control mechanism for determining the
root-mean-square value of the current flow through a lamp load;
a plurality of separate control units each having an adjustable
control mechanism and switch circuit means coupled in series
therewith, this series combination being coupled in circuit with
the dimmer circuit control mechanism, and manually operable control
circuit means for activating and disabling the switch circuit
means;
and common power supply means for energizing the individual control
circuit means in the different control units, such power supply
means inc uding means for limiting the power supply current so that
when the control circuit means in any given control unit is
operated, the control circuit means in the other control units are
automatically deactivated.
6. A light dimming system in accordance with claim 5 wherein the
control mechanism in the dimmer circuit means includes a
resistor-capacitor timing circuit and the control mechanisms in the
control units are variable resistors and the variable resistor in
any given control unit is connected in parallel with the resistor
in the dimmer circuit timing circuit when the switch circuit means
in that particular control unit is conductive.
7. A light dimming system in accordance with claim 5 wherein the
control circuit means in each control unit includes a
silicon-controlled rectifier and manually operable switch means
connected in circuit with the gate electrode thereof for triggering
such silicon-controlled rectifier.
8. A light dimming system in accordance with claim 5 wherein the
dimmer circuit means includes switch means for turning same on and
off and the power supply circuit means includes a relay having a
coil winding and switch contact means controlled thereby, such coil
winding being connected in series in the output circuit of the
power supply circuit means to provide the current limiting means
thereof, the relay switch contact means being coupled to the dimmer
circuit switch means for turning on the dimmer circuit means
whenever one of the control units is drawing current from the power
supply means.
9. A control unit for controlling the operation of a dimmer unit in
a light dimming system comprising:
three connector means;
adjustable impedance means having a first end coupled to a first of
the connector means;
a first switching device having a pair of power electrodes and a
control electrode, a first of the power electrodes being coupled to
a second end of the adjustable impedance means and a second of the
power electrodes being coupled to a second of the connector
means;
a second switching device having a pair of power electrodes and a
control electrode, a first of the power electrodes being coupled to
the control electrode of the first switching device and a second of
the power electrodes being coupled to a third of the connector
means;
capacitor means coupled between the second connector means and the
first power electrode of the second switching device;
and manually operable switch means coupled to the control electrode
of the second switching device for selectively triggering such
second switching device.
10. A control unit in accordance with claim 9 wherdn the first
switchingis a bilateral semikwnductor switching device and the
second switching device8is a silicon-controlled rectifier.
11. A control unit in accordance with claim 9 and including second
manually operable switch means coupled in circuit with the second
switching device for selectively disabling such second switching
device.
12. A control unit in accordance with claim 11 wherein the second
manually operable switch means includes first contact means coupled
to the control electrode of the second switching device for
triggering same if it is non-conductive and second contact means
mechanically coupled to the first contact means for breaking the
circuit connection between the first power electrode of the second
switching device and the control electrode of the first switching
device immediately following closure of the first contact means.
Description
BACKGROUND OF THE INVENTION
This invention relates to light dimming systems and to control
units for such systems.
One of the problems associated with lighting systems is that of the
convenient location of the switch unit or control unit for turning
the lights on and off. Large areas may dictate the use of more than
one such control unit. Conventional wiring methods would then
necessitate the use of a "three-way" or "four-way" switching
scheme. Even when only two or three control units are desired, the
wiring methods become quite complicated. Matters are further
complicated when it is desired that each control unit also provide
a light dimming function.
It has been heretofore proposed to provide a light dimming system
employing multiple remote switch units or control units for turning
the lights on and off and controlling the brightness thereof. In
the proposed system, each remote unit employs a three-position
switch and the switches in the various remote units are connected
in parallel to a reversible motor which drives the dimming
mechanism in a master dimmer unit. By operating the switch in any
given remote unit, the motor is activated to raise or lower the
lamp brightness. When the mechanism controlled by the motor reaches
the end of its travel in the minimum brightness direction, a switch
is actuated to turn off the master dimmer unit and, hence, the
lamps connected thereto. This proposed system results in a smooth
dimming action having a fixed rate of change from one control
setting to another. As many remote control units as are necessary
may be utilized. Unfortunately, however, this previously proposed
system does require the use of a motorized control and dictates a
fixed rate of change when going from one brightness level to
another. Thus, where a relatively large change is desired, the time
to accomplish same may become rather noticeable. Also, in order to
turn off the lights, it is necessary to sit and wait for the motor
to turn the control mechanism back to the zero position.
It is an object of the invention, therefore, to provide wherein new
and switching device light dimming system semiconductor multiple
remote control units wherein each device i) control unit can
instantaneously determine the lighting condition independently of
any previous setting or condition established by any of the other
remote control units.
It is another object of the invention to provide a new and improved
light dimming system employing multiple remote control units and
which does not require the use of a motor.
It is a further object of the invention to provide a new and
improved remote control unit for a light dimming system which is
adapted to be connected in parallel with any desired number of
additional such control units by a relatively simple three-wire
type conductor system.
For a better understanding of the present invention, together with
other and further objects and features thereof, reference is had to
the following description taken in connection with the accompanying
drawings, the scope of the invention being pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings:
FIG. 1 is a block diagram of a light dimming system constructed in
accordance with the present invention; and
FIG. 2 is a detailed schematic circuit design of the FIG. 1
system.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Referring to FIG. 1, there is shown a master lamp dimmer unit 10
for controlling the brightness level of a lamp or lamps contained
in a lamp load 11. The lamps in lamp load 11 may be of either the
incandescent or fluorescent type. In use, alternating-current power
is applied between power line terminals 12 and 13 and the lamp
dimmer 10 functions to control the root-mean-square (r.m.s.) value
of the current flow through the lamp load 11. A plurality of
separate remote control units 14, 15 and 16 are coupled in parallel
with one another and to the remainder of the system including the
dimmer unit 10 by a conductor system or wiring system having only
three wires 17, 18 and 19. There is no practical limit to the
number of control units which can be connected to the wires 17, 18
and 19, three being shown by way of example only. Each of the
control units is of identical construction and considering for
example the control unit 14 such control unit 14 includes a spring
loaded pushbutton switch 20 for turning on the lamp dimmer unit 10,
a spring loaded pushbutton switch 21 for turning off the dimmer
unit 10 and a rotatable control knob 22 for setting the brightness
or intensity level for the lamp load 11 when the dimmer 10 is
turned on. Each of the control units is constructed so that, by
proper manipulation of the pushbuttons and control knob at any one
of the control stations, the human operator may turn the lamp load
11 on or off and may set the brightness level for such lamp load 11
from that control unit independently of and regardless of previous
settings at any of the other control units. A direct-current power
supply 23 provides direct-current operating voltage for energizing
individual control circuits contained in the different control
units 14, 15 and 16.
Referring to FIG. 2, there is shown a schematic circuit diagram for
the light dimming system of FIG. 1 with the exception that, for
simplicity of illustration, only the first two control units 14 and
15 are shown in FIG. 2. As seen in FIG. 2, the dimmer unit 10
includes a relay 24 having a coil winding 25 for controlling a
normally-open relay switch 26. Dimmer 10 further includes a control
mechanism for determining the root-mean-square value of the current
flow through the lamp load 11 when the switch 26 is closed. For
sake of an example, lamp load 11 is assumed to be of the
incandescent type. This control mechanism includes a bilateral
semiconductor triode switching device 27 having an anode 28, a
cathode 29 and a gate electrode 30. Gate electrode 30 is controlled
by a resistor-capacitor timing circuit 31 which determines the
fraction of each half cycle of the alternating current during which
the switching device 27 is rendered conductive. Timing circuit 31
includes an adjustable resistor 32 and a capacitor 33.
Alternating-current voltage is supplied to such timing circuit 31
by means of a resistor 34 and a bilateral semiconductor diode
device 35, these elements 34 and 35 serving to regulate the
amplitude of the alternating-current voltage applied to the timing
circuit 31. Capacitor 33 is coupled to the gate electrode 30 by way
of a second bilateral semiconductor diode device 36.
At the beginning of each half cycle of the alternating-current line
voltage, the capacitor 33 is charged by way of the resistor 32, the
rate of charging being determined by the resistor-capacitor time
constant provided by resistor 32 and capacitor 33. When the charge
on capacitor 33 reaches the breakover level of the bilateral diode
device 36, such device 36 suddenly becomes conductive and suddenly
dumps the charge on capacitor 33 into the gate electrode 30 to
render the triode switching device 27 conductive. Device 27 remains
conductive until the alternating-current line voltage reverses
polarity, at which point it is turned off. Following such turn off,
the charging and triggering sequence is repeated for the next half
cycle. The resistance value of resistor 32 determines the charging
rate and, hence, the point during each half cycle at which the
triode switching device 27 is turned on. The resistance value of
resistor 32 is set to provide the lower limit or minimum brightness
level desired for the lamp load 11. This maximum resistance setting
is not normally changed during the subsequent usage of the system
with a particular lamp load.
A somewhat modified form of dimmer unit would be required for the
case of a fluorescent type lamp load, the principle difference
being that a control element for the fluorescent lamp and not the
fluorescent lamp itself would be connected in series with the
triode switching device 27. The remote control units 14, 15, etc.
and the power supply unit 23 would, however, remain the same as
hereinafter described.
The direct-current power supply circuit 23, which is common to the
various control units 14, 15, etc. includes a bridge-type rectifier
circuit 37 which is coupled to the alternating-current power line
by a transformer 38. The resulting direct-current voltage developed
across a filter or smoothing capacitor 39 is applied between the
control unit connector wires 18 and 19. The power supply circuit 23
further includes a relay 40 having a coil winding 41 and switch
contact means represented by a switch 42. Switch 42 is normally
open and is closed by the flow of current through the coil winding
41. Closure of this relay switch 42 energizes the coil winding 25
in the dimmer relay 24 which, in turn, closes the dimmer relay
switch 26 which, in turn, turns on the dimmer unit 10 and energizes
the lamp load 11. As will be seen, the coil winding 41 also
constitutes a current limiting means for limiting the power supply
current flow to the control units 14, 15, etc.
The first remote control unit 14 for controlling the operation of
the dimmer unit 10 includes an adjustable control mechanism and
switch circuit means connected in series therewith. The adjustable
control mechanism is represented by an adjustable impedance means
represented by an adjustable resistor 43 having a first end
connected to the connector means represented by the remote unit
connector wire 17. The switch circuit means is represented by a
switching device 44 having a pair of power electrodes 45 and 46 and
a control electrode 47. In the illustrated embodiment, the
switching device 44 takes the form of a bilateral semiconductor
triode switching device and, for simplicity of explanation, the
electrode 45 will be referred to as the anode, the electrode 46 as
the cathode and the electrode 47 as the gate electrode. The anode
45 is connected to the second end of the adjustable resistor 43 and
the cathode 46 is connected to the connector means represented by
the second remote unit connector wire 18. Thus, connector wires 17
and 18 serve to connect the series combination of the adjustable
resistor 43 and the switching device 44 in parallel with the timing
circuit resistor 32 in the dimmer unit control mechanism. The
adjustable element of resistor 43 is mechanically coupled to the
control knob 22 located on the front panel of the control unit
14.
The control unit 14 further includes control circuit means for
activating and disabling the switch circuit means represented by
switching device 44. This control circuit means includes a second
switching device 50 having a pair of power electrodes 51 and 52 and
a control electrode 53. In the illustrated embodiment, the
switching device 50 takes the form of a unilateral semiconductor
triode switch of the type known as a silicon-controlled rectifier.
For sake of explanation, the electrode 51 of switching device 50
will be referred to as the anode, the electrode 52 as the cathode
and the electrode 53 as the gate electrode. The anode 51 is coupled
to the gate electrode 47 of the first switching device 44 by way of
the "off" switch 21 and a resistor 54. The cathode 52 is connected
to the connector means represented by remote unit connector wire
19. A "commutating" capacitor 55 is coupled between the second
connector wire 18 and the anode 51 of device 50 by way of the "off"
switch 21. A further capacitor 56 is connected across the "off"
switch 21 for improving the switching action in the switch 21.
The control circuit portion of the control unit 14 further includes
first manually operable switch means represented by the "on" switch
20 for selectively triggering the second switching device
represented by silicon-controlled rectifier 50. Switch 20 includes
a spring-loaded normally-open switch blade 57 and a pair of switch
contacts 58 and 59, the former being connected to connector wire 18
by way of a resistor 60 and the latter being connected to the gate
electrode 53 of the silicon-controlled rectifier 50. A resistor 61
is connected between the gate electrode 53 and the lower connector
wire 19.
The control circuit portion of the control unit 14 additionally
includes second manually operable switch means represented by the
"off" switch 21 for selectively disabling the control unit 14 or,
for that matter, any of the other control units which may be in an
activated condition when the switch 21 is operated. For the control
unit 14, such control unit 14 is turned off by turning off the
silicon-controlled rectifier 50. The "off" switch 21 includes first
contact means represented by a movable spring-loaded contact member
62 and a movable spring-loaded switch blade 63 for triggering the
silicon-controlled rectifier 50 if it is non-conductive. Contact
member 62 is connected by way of a capacitor 64 to the gate
electrode 53, while switch blade 63 is connected to the anode 51 of
the silicon-controlled rectifier 50. The "off" switch 21 further
includes second contact means represented by a stationary contact
member 65 and the previously-considered movable switch blade 63 for
breaking the circuit connection between the anode 51 of the
silicon-controlled rectifier 50 and the gate electrode 47 of the
first switching device 44.
"Off" switch 21 is a "make before break" type of switch and the
mechanical coupling is such that the normally-closed second contact
means represented by elements 65 and 63 is opened immediately
following closure of the normally-open first contact means
represented by elements 62 and 63. More particularly, switch 21 is
shown in its normal or non-depressed position. The act of
depressing the pushbutton for switch 21 moves the contact member 62
downward, causing it to make contact with the switch blade 63. The
continued downward movement of contact member 62 thereafter pushes
the switch blade 63 away from the stationary contact 65 so as to
break the contact therebetween. When the pushbutton switch 21 is
released, contact member 62 and switch 63 return to the positions
shown in the drawing.
The second control unit 15 and any additional control units are of
exactly the same construction as the first control unit 14. As
such, the second control unit 15 includes an adjustable resistor 70
connected in series with a bilateral switching device 71 with this
series combination being connected in parallel with the timing
circuit resistor 32 in the dimmer unit 10 by way of connector wires
17 and 18. Control unit 15 further includes an "on" switch 72, an
"off" switch 73 and a silicon-controlled rectifier 74, the latter
being connected between the gate electrode of the bilateral
switching device 71 and the third connector wire 19 by means of the
"off" switch 73 and a resistor 75. A "commutating" capacitor 76 is
connected between the second connector wire 18 and the "off" switch
73. The "off" switch 73 is of the same "make before break" type as
previously considered and, as such, includes a movable contact
member 77, a switch blade 78 and a stationary contact member 79.
Contact member 77 is connected to the gate electrode of
silicon-controlled rectifier 74 by way of a capacitor 80.
OPERATION OF THE ILLUSTRATED EMBODIMENT
Considering now the operation of the circuits shown in FIG. 2, each
of the remote control units 14, 15, etc. is capable of turning on
the dimmer unit 10 and lamp load 11, turning off the dimmer unit 10
and lamp load 11 and setting the brightness level for the lamp load
11 independently of and regardless of previous settings or
conditions in any of the other control units.
It will first be assumed that none of the control units 14 and 15
(and any others) is in an activated or conductive condition. In
this case, no direct current is being drawn from the direct current
power supply circuit 23 and the relay switch 42 therein remains
open. This opens the circuit for the dimmer relay coil 25 and
causes the dimmer relay switch 26 to be open. With switch 26 open,
dimmer unit 10 and lamp load 11 are turned off. Assuming now that
the lamp load 11 is to be turned on by means of the control unit
14, this is accomplished by momentarily depressing the pushbutton
"on" switch 20 to move the switch blade 57 against the stationary
contact 58. This closure of switch 20 supplies a pulse of current
to the gate electrode 53 of the silicon-controlled rectifier 50.
This turns on or renders conductive the silicon-controlled
rectifier 50. This, in turn, causes direct current to flow by way
of the connector wire 18, into the cathode 46 and out of the gate
electrode 47 of the bilateral switching device 44, through resistor
54, switch contact member 65 and switch blade 63 of "off" switch
21, into the anode 51 and out of the cathode 52 of the
silicon-controlled rectifier 50 and back to the direct-current
power supply circuit 23 by way of the lower connector wire 19.
Within the power supply circuit 23, this direct current flows
through the relay coil winding 41 to close the switch 42. This
enables the alternating line current to flow through the dimmer
relay coil 25 to close the dimmer relay switch 26. This turns on
the dimmer 10 and the lamp load 11.
When the silicon-controlled rectifier 50 is conductive, its
internal anode-to-cathode impedance is very small. When turned on,
the silicon-controlled rectifier 50 remains conductive until the
voltage between the anode and cathode thereof is reduced to
practically zero or reversed in polarity. With silicon-controlled
rectifier 50 conductive, the commutating capacitor 55 charges up to
a direct-current voltage level corresponding to the direct-current
voltage difference between connector wires 18 and 19.
The direct current flow between the cathode 46 and the gate
electrode 47 of the bilateral switching device 44 when the
silicon-controlled rectifier 50 is conductive renders the bilateral
switching device 44 conductive. This, in effect, connects the
variable resistor 43 across the two connector wires 17 and 18 and,
hence, in parallel with the timing circuit resistor 32 in the
dimmer unit 10. This enables the variable resistor 43 to vary the
resistance in the resistor-capacitor time constant circuit 31 and,
hence, to vary the brightness of the lamp load 11. Increasing the
time constant decreases the lamp brightness and vice versa.
When the silicon-controlled rectifier 50 is turned off, the
bilateral switching device 44 is also turned off due to the absence
of gate current flow between the cathode 46 and the gate electrode
47 thereof. This, in effect, disconnects the variable resistor 43
from the connector wires 17 and 18 so that it has no effect on the
timing circuit 31 in the dimmer 10. Silicon-controlled rectifier 50
is turned off by momentarily depressing the pushbutton for the
"off" switch 21. This breaks the connection between the stationary
contact member 65 and the switch blade 63 to interrupt the direct
current flow through silicon-controlled rectifier 50.
There will now be considered the case where one of the control
units, for example, the first control unit 14, is conductive or
turned on and it is desired to switch control of the dimmer 10 to
another of the control units, for example, the second control unit
15. This is accomplished by momentarily depressing the pushbutton
for the "on" switch 72 in the second unit 15. This turns on the
silicon-controlled rectifier 74 in the second unit 15 and, at the
same time, the commutating action of the commutating capacitor 76
in the second unit 14 turns off the silicon-controlled rectifier 50
in the first unit 14. In particular, the commutating capacitor 76
is initially discharged. When the silicon-controlled rectifier 74
turns on, this, in effect, connects the lower end of the capacitor
76 to the lower connector wire 19. The commutating capacitor 55 in
the first unit 14 then acts like a battery and causes a charging
current to flow through the second capacitor 76, through the
now-conductive second silicon-controlled rectifier 74 and through
the first silicon-controlled rectifier 50 in the reverse direction.
This reverse current flow through the first silicon-controlled
rectifier 50 turns off such silicon-controlled rectifier 50. Thus,
the second unit 15 is turned on and remains on and the first unit
14 is turned off and remains off. This commutating action is
facilitated by the inductance of the relay coil winding 41 in the
power supply 23, which relay coil winding 41, in effect, limits the
magnitude of the direct current flow to the control units such that
only one silicon-controlled rectifier may be in conduction at any
given time.
With the second control unit 15 turned on, its bilateral switching
device 71 is conductive and its variable resistor 70 is, in effect,
connected in parallel across the timing circuit resistor 32 in the
dimmer 10. At the same time, the bilateral switching device 44 in
the first unit 14 is non-conductive so that the first variable
resistor 43 is no longer connected to the dimmer timing circuit 31.
Thus, the variable resistor in only one of the control units will
have any effect on the dimmer timing circuit 31 at any given
time.
There will now be considered the case where a first of the control
units, for example, the control unit 14, is turned on and it is
desired to turn the dimmer 10 and lamp load 11 off by manipulation
of a second of the control units for example, the control unit 15,
which at that moment is in an off condition. This is accomplished
by momentarily depressing the pushbutton for the "off" switch 73 in
the second unit 15. The first thing that happens is that the
movable contact member 77 contacts the switch blade 78 in the
switch 73. This triggers the silicon-controlled rectifier 74 to
turn same on. This turns off the silicon-controlled rectifier 50 in
the first unit 14 for the reason previously mentioned. This
transfers control of the system to the second unit 15. Shortly
thereafter, the continued movement of the switch blade 78 breaks
the contact with the stationary contact member 79 in the switch 73.
This breaks or opens the anode-to-cathode circuit of the
silicon-controlled rectifier 74 to turn same off. With this
accomplished, all of the control units 14, 15, etc. are now turned
off. This discontinues the flow of current through the relay coil
winding 41, causing relay switch 42 to open. This, in turn, opens
the relay switch 26 in the dimmer 10, thus deactivating the dimmer
10 and turning off the lamp load 11.
Any desired number of control units can be connected to the system
and, as seen from the foregoing, each of these control units is
capable of turning on, turning off or setting the brightness level
of the lamp load 11 regardless of the previous setting or condition
of any of the other control units. At the same time, the system
wiring remains quite simple regardless of the number of control
units used since each control unit requires only three conductors
and all of the control units are connected in parallel so that a
three-wire bus may be utilized to pick up all of the control units
throughout a given area.
While there has been described what is at present considered to be
a preferred embodiment of this invention, it will be obvious to
those skilled in the art that various changes and modifications may
be made therein without departing from the invention, and it is,
therefore, intended to cover all such changes and modifications as
fall within the true spirit and scope of the invent.
* * * * *