U.S. patent application number 14/869478 was filed with the patent office on 2017-03-30 for system and method for predicting mechanical failure.
The applicant listed for this patent is General Electric Company. Invention is credited to Anthony Paul Fama, Corey Jackson, Kevin Michael Jones, Prabhakar Neti.
Application Number | 20170087990 14/869478 |
Document ID | / |
Family ID | 58406559 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170087990 |
Kind Code |
A1 |
Neti; Prabhakar ; et
al. |
March 30, 2017 |
SYSTEM AND METHOD FOR PREDICTING MECHANICAL FAILURE
Abstract
A system and method for monitoring a motor of a vehicle system
monitor operating conditions of the vehicle system and determine
whether the operating conditions of the vehicle system match
designated operating conditions. Responsive to determining that the
operating conditions of the vehicle system that are monitored match
the designated operating conditions, an electrical signature
representative of an electric current supplied to the motor of the
vehicle system is examined and damage to one or more of the motor
of the vehicle system or a mechanical coupling of the motor to one
or more of a wheel or axle of the vehicle system is identified
based on the electrical signature that is examined.
Inventors: |
Neti; Prabhakar; (Rexford,
NY) ; Jones; Kevin Michael; (Erie, PA) ; Fama;
Anthony Paul; (Erie, PA) ; Jackson; Corey;
(Erie, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
58406559 |
Appl. No.: |
14/869478 |
Filed: |
September 29, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L 3/0061
20130101 |
International
Class: |
B60L 3/00 20060101
B60L003/00 |
Claims
1. A method comprising: monitoring operating conditions of a
vehicle system; determining whether the operating conditions of the
vehicle system match designated operating conditions; responsive to
determining that the operating conditions of the vehicle system
that are monitored match the designated operating conditions,
examining an electrical signature representative of an electric
current supplied to a propulsion system of the vehicle system; and
identifying damage to propulsion system based on the electrical
signature that is examined.
2. The method of claim 1, wherein the operating conditions include
at least one of a speed at which a motor of the propulsion system
rotates and a torque generated by the motor.
3. The method of claim 1, wherein the operating conditions include
both a speed at which a motor of the propulsion system rotates and
a torque generated by the motor.
4. The method of any other clause, wherein the designated operating
conditions include both a designated speed at which a motor of the
propulsion system rotates and a designated torque generated by the
motor.
5. The method of claim 1, wherein the electrical signature includes
a frequency domain spectrum of one or more electrical
characteristics of the current supplied to the propulsion
system.
6. The method of claim 5, wherein the damage is identified
responsive to determining that the electrical signature includes an
increased magnitude at one or more fault frequencies associated
with the damage to the propulsion system.
7. A method comprising: monitoring operating conditions of a
propulsion system of a vehicle system during a baseline time
period; monitoring one or more electrical characteristics of
current supplied to the propulsion system during the baseline time
period; examining one or more electrical signatures of the
propulsion system to identify at least one electrical signature
having reduced variances in magnitude at one or more frequencies
associated with damage to the propulsion system; and determining
one or more sets of designated operating conditions of the
propulsion system based on the one or more electrical signatures
that are examined, wherein the one or more sets of designated
operating conditions are used to determine which of subsequently
monitored electrical characteristics of the current are to be
examined to identify the damage to the propulsion system.
8. The method of claim 7, wherein the operating conditions include
both a speed at which a motor of the propulsion system rotates and
a torque generated by the motor.
9. The method of claim 7, wherein the designated operating
conditions include both a designated speed at which a motor of the
propulsion system rotates and a designated torque generated by the
motor.
10. The method of claim 7, wherein the one or more electrical
signatures includes a frequency domain spectrum of one or more
electrical characteristics of the current supplied to the
propulsion system.
11. The method of claim 10, further comprising: subsequently
determining whether additional operating conditions of the vehicle
system match the designated operating conditions of at least one of
the sets of the one or more designated operating conditions;
responsive to determining that the additional operating conditions
of the vehicle system match the designated operating conditions of
the at least one of the sets, examining an additional electrical
signature of the current supplied to the motor; and identifying the
damage to the propulsion system based on the additional electrical
signature that is examined.
12. A system comprising: one or more sensors configured to measure
operating conditions of a vehicle system; and a controller
configured to determine whether the operating conditions of the
vehicle system match designated operating conditions, the
controller also configured to examine an electrical signature
representative of an electric current supplied to a motor of the
vehicle system responsive to determining that the operating
conditions of the vehicle system that are monitored match the
designated operating conditions, wherein the controller also is
configured to identify damage to one or more of the motor of the
vehicle system or a mechanical coupling of the motor to one or more
of a wheel or axle of the vehicle system based on the electrical
signature that is examined.
13. The system of claim 12, wherein the operating conditions
include a speed at which the motor rotates.
14. The system of claim 12, wherein the operating conditions
include a torque generated by the motor.
15. The system of claim 12, wherein the operating conditions
include both a speed at which the motor rotates and a torque
generated by the motor.
16. The system of claim 12, wherein the designated operating
conditions include a designated speed at which the motor
rotates.
17. The system of claim 12, wherein the designated operating
conditions include a designated torque generated by the motor.
18. The system of claim 12, wherein the designated operating
conditions include both a designated speed at which the motor
rotates and a designated torque generated by the motor.
19. The system of claim 12, wherein the electrical signature
includes a frequency domain spectrum of one or more electrical
characteristics of the current supplied to the motor.
20. The system of claim 12, wherein the controller is configured to
identify the damage responsive to determining that the electrical
signature includes an increased magnitude at one or more fault
frequencies associated with the damage to the one or more of the
motor or the mechanical coupling.
Description
FIELD
[0001] One or more embodiments of the subject matter described
herein relate to systems for monitoring electric components, such
as traction motors, alternators, transmission gearings, etc., of a
vehicle. While certain embodiments are described in terms of
traction motors of off-highway vehicles (OHV), such as mining
vehicles or other vehicles that are not designed or not permitted
for travel on public roadways, the subject matter described herein
optionally may apply to other vehicles.
BACKGROUND
[0002] Known vehicles may include several electric motors, such as
three-phase alternating current (AC) traction motors, that receive
three-phase AC to power the motors. With respect to each motor,
different phases of the current are passed to different conductive
coils disposed in a stator of the motor. The current generates a
magnetic field in the stator and causes a rotor of the motor to
rotate within the stator. The rotor may be coupled with an axle or
wheel of the vehicle by one or more gears or other couplings.
Rotation of the rotor causes rotation of the axle and wheel to
propel the vehicle.
[0003] Several mechanical components may be used to enable rotation
of the rotor within the stator of the motor. For example, bearings
may be disposed between the rotor and the stator to center the
rotor in the stator and allow the rotor to rotate at relatively
high speeds within the stator. Gears and/or other coupling
components may be coupled with the rotor to translate rotation of
the rotor to rotation of an axle or wheels. Over time, one or more
of the bearings, gears, and/or other coupling components may begin
to fail. For example, friction between a bearing and the rotor or
stator, friction between gears, and/or friction between two or more
other components of the motor may increase as the bearing, gear, or
other component begins to mechanically fail. If the motor having
the failing bearing, gear, or other component is not identified in
time, the failing bearing, gear, or other component may seize or
lock up and cause the motor to fail. Once the motor fails, the
motor can no longer operate to propel the vehicle.
BRIEF DESCRIPTION
[0004] In one embodiment, a method (e.g., for monitoring a
propulsion system of a vehicle system) includes monitoring
operating conditions of the vehicle system, determining whether the
operating conditions of the vehicle system match designated
operating conditions, examining an electrical signature
representative of an electric current supplied to the propulsion
system of the vehicle system responsive to determining that the
operating conditions of the vehicle system that are monitored match
the designated operating conditions, and identifying damage to one
or more of the propulsion system of the vehicle system or a
mechanical coupling of the propulsion system to one or more of a
wheel or axle of the vehicle system based on the electrical
signature that is examined.
[0005] In another embodiment, another method (e.g., for monitoring
a propulsion system of a vehicle system) includes monitoring
operating conditions of the propulsion system of the vehicle system
during a baseline time period, monitoring one or more electrical
characteristics of current supplied to the propulsion system during
the baseline time period, examining one or more electrical
signatures of the propulsion system to identify at least one
electrical signature having reduced variances in magnitude at one
or more frequencies associated with damage to one or more of the
propulsion system or a mechanical coupling of the propulsion system
to one or more of a wheel or an axle of the vehicle system, and
determining one or more sets of designated operating conditions of
the propulsion system based on the one or more electrical
signatures that are examined. The one or more sets of designated
operating conditions are used to determine which of subsequently
monitored electrical characteristics of the current are to be
examined to identify the damage to the one or more of the
propulsion system or the mechanical coupling of the propulsion
system.
[0006] In another embodiment, a system (e.g., a monitoring system)
includes one or more sensors and a controller. The one or more
sensors are configured to measure operating conditions of a vehicle
system. The controller is configured to determine whether the
operating conditions of the vehicle system match designated
operating conditions. The controller also is configured to examine
an electrical signature representative of an electric current
supplied to a propulsion system of the vehicle system responsive to
determining that the operating conditions of the vehicle system
that are monitored match the designated operating conditions. The
controller also is configured to identify damage to one or more of
the propulsion system of the vehicle system or a mechanical
coupling of the propulsion system to one or more of a wheel or axle
of the vehicle system based on the electrical signature that is
examined.
[0007] In another embodiment, another system (e.g., a monitoring
system) includes one or more sensors and a controller). The one or
more sensors are configured to measure operating conditions of a
propulsion system of a vehicle system during a baseline time
period. The controller is configured to monitor one or more
electrical characteristics of current supplied to the propulsion
system during the baseline time period, and to examine one or more
electrical signatures of the propulsion system to identify at least
one electrical signature having reduced variances in magnitude at
one or more frequencies associated with damage to one or more of
the propulsion system or a mechanical coupling of the propulsion
system to one or more of a wheel or an axle of the vehicle system.
The controller is configured to determine one or more sets of
designated operating conditions of the propulsion system based on
the one or more electrical signatures that are examined. The one or
more sets of designated operating conditions are used by the
controller to determine which of subsequently monitored electrical
characteristics of the current are to be examined to identify the
damage to the one or more of the propulsion system or the
mechanical coupling of the propulsion system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The subject matter described herein will be better
understood from reading the following description of non-limiting
embodiments, with reference to the attached drawings, wherein
below:
[0009] FIG. 1 illustrates one embodiment of a vehicle system;
[0010] FIG. 2 illustrates a schematic diagram of one embodiment of
a monitoring system;
[0011] FIG. 3 illustrates a perspective view of raceways and a
bearing cage of a propulsion system shown in FIG. 1 according to
one example;
[0012] FIG. 4 illustrates an electrical signature for the
propulsion system shown in FIG. 1 operating according to a first
set of operating conditions according to one example;
[0013] FIG. 5 illustrates an electrical signature for the
propulsion system shown in FIG. 1 operating according to a second
set of operating conditions according to one example;
[0014] FIG. 6 illustrates an electrical signature for the
propulsion system shown in FIG. 1 operating according to a third
set of operating conditions according to one example;
[0015] FIG. 7 illustrates an electrical signature for the
propulsion system shown in FIG. 1 operating according to a fourth
set of operating conditions according to one example;
[0016] FIG. 8 illustrates an electrical signature for the
propulsion system shown in FIG. 1 operating according to a fifth
set of operating conditions according to one example;
[0017] FIG. 9 illustrates an electrical signature for the
propulsion system shown in FIG. 1 operating according to a sixth
set of operating conditions according to one example; and
[0018] FIG. 10 illustrates a flowchart of one embodiment of a
method for monitoring a vehicle system and/or a propulsion system
of the vehicle system.
DETAILED DESCRIPTION
[0019] Reference will be made below in detail to embodiments of the
inventive subject matter, examples of which are illustrated in the
accompanying drawings. Wherever possible, the same reference
numerals used throughout the drawings refer to the same or like
parts. Although example embodiments of the inventive subject matter
are described with respect to three phase alternating current
electric motors for vehicles, embodiments also may be applicable
for use with electric motors generally.
[0020] At least one embodiment described herein relates to a system
and method that monitors electric energy (e.g., electric current,
voltage, inductance, or any combination thereof) that is supplied
to a propulsion system in order to generate a motor electrical
signature of the electrical energy. This signature can represent
current and/or voltage spectra, which can be related to the defects
in bearings, gears, or the like, included in the motor and/or that
couple the motor with an axle or wheel. For example, a damaged
bearing will produce several mechanical vibrations that are
transformed into the electrical signatures of the traction motor.
The magnitude of these mechanical vibrations for a given system
will be very clear at certain operating conditions, such as certain
designated motor speeds and torques.
[0021] These vibrations, however, may not be as clearly defined
(relative to other areas of the signature). The vehicle system is
operated to characterize one or more sets of designated operating
conditions (e.g., sets of designated motor speeds and torques)
where vibrations caused by faulty bearings or other mechanical
faults of the motor (or associated with the motor) are more likely
to appear in the signatures of the motor than at other operating
conditions. During later operation, the voltage and/or current of
one or more phases of current supplied to the motor is monitored
during time periods that the vehicle system operates using one or
more of the sets of designated operating conditions. These voltages
and/or currents are used to generate voltage or current spectra,
which represent electrical signatures of the motor at the
designated operating conditions. The signatures associated with the
voltages and/or currents obtained during operation at the
designated operating conditions are examined in order to determine
whether one or more vibrations or peaks in the signatures indicate
damage to the motor (or associated bearings, gears, etc.).
[0022] The electrical signatures described herein include
representations of one or more characteristics of the electrical
energy supplied to a motor. For example, a motor electrical
signature can be a frequency spectrum of one or more of the three
phases of current or voltage that is supplied to a three-phase
alternating current (AC) motor. In another example, the motor
electrical signature can be a time-varying inductance
characteristic of the motor. Alternatively, another type of
signature can be generated based on the energy that is supplied to
the motor.
[0023] Once a motor is identified as having a faulty motor,
bearing, gear, or the like, based on examination of the electrical
signature(s) at the designated operating conditions, one or more
embodiments of the systems and methods described herein may take
additional responsive actions. For example, upon identification of
a potential mechanical failure of a motor, a control signal may be
generated that is communicated to a controller of the vehicle
system that controls the tractive efforts and/or braking efforts
(e.g., retarding efforts) provided by the vehicle system that
includes the motor. The control signal may automatically change the
tractive efforts and/or retarding efforts, such as by slowing down
or stopping movement of the vehicle. Alternatively, the control
signal may provide a notification to an operator of the vehicle
(e.g., instructions that are displayed on a display device) that
instructs the operator to slow down or stop movement of the
vehicle. In another embodiment, the control signal may include an
alarm signal that notifies and warns the operator of the identified
impending mechanical failure. In another example, the output signal
may be communicated to a location disposed off-board of the vehicle
system, such as a dispatch center or a repair center that is
remotely located from the vehicle. In response to receiving the
output signal, the off-board location may schedule a maintenance
operation for the vehicle system, such as a scheduled examination
and/or repair to the motor associated with the impending mechanical
failure that is identified. The off-board location may transmit a
responsive signal to the vehicle system that controls the tractive
efforts of the vehicle system, or instructs an operator of the
vehicle system to change the tractive efforts of the vehicle
system, to stop the vehicle system or cause the vehicle system to
travel to a designated maintenance facility where the motor can be
examined and/or repaired. In one embodiment, the output signal from
the vehicle system may include information related to the
maintenance operation to be performed on the motor, such as a
potential identification of the motor and/or of a bearing or gear
that may be the cause of the impending mechanical failure that is
identified.
[0024] FIG. 1 illustrates one embodiment of a vehicle system 100.
The vehicle system 100 represents an OHV, such as a mining haul
truck, having a propulsion system that includes one or more
traction motors 102, alternators, transmission gearings, etc.,
operably connected with wheels 104 of the vehicle system 100. The
motors 102 may be operably connected with the wheels 104 by gears
or the like. The motors 102 are powered by electric current
received from a power source, such as an alternator of the vehicle
system 100. In operation, the motors 102 receive current from the
power source and rotate the wheels 104 to propel the vehicle system
100. If a motor 102 (or gears to which the motor 102 is connected)
is damaged, then an electrical signature of the current and/or
voltage supplied to that motor 102 may include peaks representative
of the damage, as described herein. Not all embodiments of the
subject matter described herein are limited to mining vehicles,
however. For example, one or more embodiments of the subject matter
described herein may be used with other vehicles, such as rail
vehicles, electric automobiles, marine vessels, stationary
power-generating systems, or the like.
[0025] FIG. 2 illustrates a schematic diagram of one embodiment of
a monitoring system 200. The monitoring system 200 can be used to
monitor the health of the propulsion system of vehicle systems 100,
such as by determining whether motors, bearings, gears,
alternators, or the like, of the propulsion system are damaged
and/or whether mechanical couplings 204 between the motors 102 and
wheels 104 are damaged. The mechanical couplings 204 can represent
gears, axles, or the like, that transfer rotation of the motor 102
to rotation of the wheel 104. The monitoring system 200 includes a
controller 202, which can represent hardware circuitry that
includes and/or is connected with one or more processors (e.g.,
microprocessors, integrated circuits, application specific
integrated circuits, field programmable gate arrays, or other
electronic logic-based devices) that perform the operations
described herein. In one aspect, the controller 202 may include a
computing device that is specially programmed to monitor operation
of the vehicle system 100 and/or motors 102 in order to identify
damage to the motors 102 and/or associated gears, bearings,
etc.
[0026] The controller 202 optionally may control operation of the
vehicle system 100, such as by controlling the torque and/or speed
of the motors 102 (e.g., based on operator input). The controller
202 may be manually controlled by an operator and/or automatically
controlled. For example, the controller 202 may change operating
speeds and/or torques of one or more of the motors 102 based on a
manually adjustable throttle and/or may automatically change
operating speeds of one or more of the motors 102 based on
detection of damage to the motor 102, such as a motor 102 that is
identified by the system 100 as likely having one or more failed
components (e.g., bearings) and that may require service relatively
soon.
[0027] The monitoring system 200 can be disposed onboard the
vehicle system 100, and/or may be retrofitted to an existing
vehicle system 100. The monitoring system 200 monitors electrical
energy that is supplied to the motors 102 by a power source 206.
While only one motor 102 and wheel 104 are shown in FIG. 2, the
monitoring system 200 may concurrently monitor electrical energy
supplied to multiple motors 102 by the same or different power
sources 206. The power source 206 is an assembly that generates
electric current or voltage, such as an engine coupled with an
alternator or generator, a battery, or the like. The current or
voltage is supplied to the motors 102 to cause the motors 102 to
rotate. In one embodiment, the power source 206 provides an
alternating current that is supplied to the motors 102 as a
three-phase alternating current, such as an alternating current
that includes three phases of the current that are offset from each
other.
[0028] One or more electrical sensors 208 may be coupled with or
disposed near the power source 206 and/or motor 102 to measure one
or more characteristics of the electrical energy that is provided
to the motor 102 from the power source 206. In one embodiment, the
electrical sensor 208 includes a current sensor that measures the
electric current supplied to the motor 102 as a characteristic of
the electric energy that is supplied to the motor 102. The
electrical sensor 208 can monitor different phases of an
alternating current that is fed to the motor 102. Alternatively,
the electrical sensor 208 may be a voltage sensor that measures the
voltages that are supplied to the motor 102 from the power source
206. In another embodiment, the electrical sensor 208 may be
another sensor that measures another electric characteristic of the
energy that is delivered from the power source 206 to the motor
102, such as inductances, impedances, resistances, power (e.g.,
watts), and the like, of the electrical energy that is delivered to
the motor 102 from the power source 206.
[0029] In one embodiment, the controller 202 may examine the
currents and/or voltages measured by the one or more electrical
sensors 208 to determine torques generated by the motor 102. For
example, the torque generated by the motor 102 may be proportional
to the current and/or voltage consumed by the motor 102 (and/or
proportional to the efficiency of the motor 102 and inversely
proportional to the rotational speed of the motor 102). Using the
measured current and/or voltage, the controller 202 can calculate,
estimate, or otherwise determine the torque of the motor 102.
[0030] One or more speed sensors 212 also may be coupled with or
disposed near the motor 102 to measure speeds of the motor 102,
such as the rotational speeds of the motor 102. The electrical
characteristics, torques, and/or motors speeds can be communicated
from the sensors 208, 210, 212 to the controller 202 via one or
more wired and/or wireless connections.
[0031] One or more input and/or output devices 214 ("Input/Output
Device(s)" in FIG. 2) may be disposed onboard the vehicle system
100. The input/output device 214 can include a monitor that
visually presents information, a printer that prints information
onto paper or another medium, a speaker that audibly presents
information, a touchscreen that displays information and/or
receives information, transceiving circuitry that communicates
signals to off-board locations, an electronic mouse, a keyboard,
stylus, or the like.
[0032] The system 200 includes a tangible and non-transitory
computer-readable storage medium, such as a memory 216. The memory
216 may include a hard drive, flash drive, EEPROM, CD-ROM, DVD-ROM,
and the like, that stores instructions that are readable by the
controller 202. The instructions may direct the controller 202 to
perform various operations. The memory 216 may store designated
operating conditions, measured electrical characteristics, measured
speeds, measured torques, electrical signatures, or the like, of
the motor 102.
[0033] FIG. 3 illustrates a perspective view of raceways 300, 302
and a bearing cage 304 of the motor 102 shown in FIG. 1 according
to one example. Also shown in FIG. 3 is a magnified view of a
portion of the raceways 300, 302 and bearing cage 304. The bearing
cage 304 holds several bearings that allow one or more of the
raceways 300, 302 to rotate relative to each other. If the raceways
300, 302 and/or bearings 304 become damaged, then the monitoring
system 200 can detect the damage based on the electrical signatures
of the motor 102 without an operator having to take the motor 102
apart for a visual inspection.
[0034] FIGS. 4 through 9 illustrate electrical signatures 400, 500,
600, 700, 800, 900 for the same motor 102 operating using different
operating conditions according to several examples. The electrical
signatures shown in FIGS. 4 through 9 are frequency spectra of the
electrical characteristics measured by the electrical sensor 208
during operation of the motor 102 in the different operating
conditions. The signatures are shown alongside a horizontal axis
402 representative of frequencies and a vertical axis 404
representative of magnitudes of the various frequencies. Different
electrical signatures may be determined for different sets of
operating conditions. For example, a first electrical signature may
be determined for a first motor speed and a first torque; a
different, second electrical signature may be determined for a
different, second motor speed and/or a different, second torque;
and so on.
[0035] The electrical signatures may represent the characteristics
measured for a single phase of the current supplied to the motor
102 in one embodiment. Similar signatures may be obtained or
generated by the controller 202 for other phases of the current
supplied to the motor 102. The following table indicates the
operational conditions of the motor 102 for the different
signatures in FIGS. 4 through 9:
TABLE-US-00001 Signature FIG. Speed (rpm) Torque (ft * lbs) 400 4
225 10,000 500 5 225 15,000 600 6 300 5,000 700 7 300 10,000 800 8
300 15,000 900 9 350 10,000
[0036] Different frequencies within the signatures may be
associated with different faults of the motor 102 and/or couplings
204. Additionally, peaks occur within the signatures at frequencies
representative of the speeds at which the motor 102 is operating.
The frequencies associated with the faults of the motor 102 and/or
couplings 204 can be derived from the peaks representative of the
motor speeds. For example, the signatures 400, 500 include
fundamental frequency peaks 406, 506 at frequencies of 11.4 Hz and
11.9 Hz (which represent the rotational speed of the motor 102 of
225 rpm), the signatures 600, 700, 800 include fundamental
frequency peaks 606, 706, 806 at frequencies of 15.3 Hz, 15.56 Hz,
and 15.83 Hz (which represent the rotational speed of the motor 102
of 300 rpm), and the signature 900 includes a fundamental frequency
peak 906 at a frequency of 18.03 Hz (which represents the
rotational speed of the motor 102 of 350 rpm).
[0037] Based on the fundamental frequency peak for a signature, the
controller 202 can determine additional fault frequencies. The
fault frequencies represent frequencies at which peaks occur if
damage to the motor 102 and/or couplings 204 is present. In one
embodiment, the fault frequencies can be determined from:
f.sub.s=|f.sub.fundamental.+-.kf.sub.bearing| (Eqn. 1)
where f.sub.s represents fault frequencies, f.sub.fundamental
represents the fundamental frequency peak for the signature being
examined, k represents one or more integer values (e.g., 1, 2, 3,
etc.), and f.sub.bearing represents a frequency associated with
damage to the motor 102 and/or couplings 204.
[0038] The frequency associated with damage to the motor and/or
couplings may be determined from:
f bearing = f desig * v motor .tau. ( Eqn . 2 ) ##EQU00001##
where f.sub.desig represents a designated frequency associated with
one or more types of damage, v.sub.motor represents the measured
rotational speed of the motor 102 (in rpm), and .tau. represents
the measured torque of the motor 102 (in foot pounds). The
designated frequency (f.sub.desig) can vary based on the type of
motor 102, type of damage, etc., and may be determined
experimentally. In one embodiment, the designated frequency
(f.sub.desig) for a damaged bearing is 68.6 Hz, although one or
more other frequencies may be used. As a result, the designated
frequency (f.sub.bearing) is 15.43 Hz, as determined from Equation
#2 above.
[0039] In order to examine the signatures for damaged bearings, the
controller 202 may examine the signatures at the fault frequencies
to determine if one or more peaks are present in the signatures at
one or more of the fault frequencies. For example, for the
signature 400 (where the motor 102 operates at 225 rpm and produces
10,000 ft*lbs of torque and has a fundamental peak frequency of
11.4 Hz), the fault frequencies occur at absolute values of 11.4
Hz.+-.k*15.3 Hz, such as the frequencies 9.14 Hz, 29.72 Hz, 32.0
Hz, etc. The table below lists several fault frequencies for
different operating conditions of the motor 102 and different
fundamental frequencies of the motors 102:
TABLE-US-00002 Operating Conditions Fundamental (rpm/ft * lbs)
Frequency (Hz) Fault Frequencies (Hz) 225/5,000 11.4 4.00, 19.43,
26.86, 34.87, 42.30, 50.30, 57.73, 65.74, 73.17, 88.60, etc.,
225/10,000 11.7 3.76, 19.20, 27.10, 34.63, 42.53, 50.07, 57.97,
65.50, 73.40, 88.84, etc., 225/15,000 11.9 3.50, 18.93, 27.36,
34.37, 42.80, 49.80, 58.23, 65.24, 73.67, 89.10, etc., 300/5,000
15.3 5.28, 25.86, 35.88, 46.44, 56.46, 67.02, 77.04, 87.60, 97.62,
118.20, etc., 300/10,000 15.56 5.28, 25.86, 35.88, 46.44, 56.46,
67.02, 77.04, 87.60, 97.62, 118.20, etc., 300/15,000 15.83 4.74,
36.41, 25.32, 45.90, 56.99, 66.48, 77.57, 87.06, 98.15, 118.73,
etc., 350/10,000 18.03 5.97, 29.98, 42.04, 53.99, 66.05, 78.0,
90.06, 102.01, 114.07, 138.08, etc.,
[0040] The controller 202 may examine the electrical signatures
associated with different operating conditions at the corresponding
fault frequencies to determine if a peak exists at or near (e.g.,
within a designated range, such as 1 Hz, 0.5 Hz, or another value)
the fault frequencies. If a peak exists, then the controller 202
may determine that the motor 102 and/or couplings 204 are damaged.
Otherwise, the controller 202 may determine that the signature does
not indicate that the motor 102 and/or couplings 204 are
damaged.
[0041] In operation, the monitoring system 200 may monitor
operations of the vehicle system 100 during a baseline time period
in order to determine baseline operating conditions. The baseline
time period may include a time period where there is no damage to
the motors 102, couplings 204, or the like, such as after
manufacture, repair, inspection, etc., of the motors 102, couplings
204, or vehicle system 100. In one aspect, the baseline time period
can include several days or weeks after the vehicle system 100 is
first placed into service following manufacture of the vehicle
system 100 or motors 102. During the baseline time period, the
operating conditions of the vehicle system 100 are monitored. The
operating conditions can include the speeds at which the motors 102
operate (as measured by the speed sensor 212) and the torques
generated by the motors 102.
[0042] The controller 202 can monitor these operating conditions
during the baseline time period and determine electrical signatures
of one or more motors 102 using the electrical characteristics that
are measured by the electrical sensor 208 when the various
operating conditions are monitored. The controller 202 can examine
the electrical signatures generated from electrical characteristics
measured at different operating conditions of the vehicle system
100 to determine which operating conditions provide improved
conditions for detecting damage to the motor 102 and/or couplings
204 relative to other operating conditions.
[0043] Some operating conditions result in electrical signatures
that have less noise (e.g., less variations in magnitude) in
portions of the signatures that are outside of (e.g., that do not
include) the fundamental frequency and/or the fault frequencies
than signatures obtained during different operating conditions.
With respect to the signatures shown in FIGS. 4 through 9, the
signatures 400, 800, 900 include smaller noise when compared to the
signatures 500, 600, 700. The variances in the signatures 400, 800,
900 are smaller in the frequencies that do not include the
fundamental or fault frequencies than the variances in the
signatures 500, 600, 700 for the same frequencies. Accordingly, the
controller 202 may select the operating conditions associated with
the signatures 400, 800, 900 as designated operating conditions for
examining the motor 102 and/or couplings 204. The operating
conditions associated with the other signatures may not be selected
as designated operating conditions. The designated operating
conditions may be selected from the signatures generated based on
electrical characteristics measured during the baseline time
period. In the illustrated examples, the designated operating
conditions include three sets of different operating conditions,
with a first set including a motor speed of 225 rpm and a torque of
10,000 ft*lbs (e.g., the signature 400 shown in FIG. 4), a second
set including a motor speed of 300 rpm and a torque of 15,000
ft*lbs (e.g., the signature 800 shown in FIG. 8), and a third set
including a motor speed of 350 rpm and a torque of 10,000 ft*lbs
(e.g., the signature 900 shown in FIG. 9).
[0044] Following the baseline time period, the controller 202 may
continue to monitor the electrical characteristics of the current
supplied to the motor 102 to identify damage to the motor 102
and/or couplings 204. In one embodiment, the controller 202 may
monitor the operating conditions of the motor 102 to determine
whether the current operating conditions are the same as or within
a designated range of (e.g., within 1%, 3%, 5%, or another limit)
the designated operating conditions in one or more sets of the
designated operating conditions. For example, the controller 202
may monitor the operating conditions to determine when the motor
102 has a speed of 225 rpm and a torque of 10,000 ft*lbs, when the
motor has a speed of 300 rpm and a torque of 15,000 ft*lbs, or when
the motor has a speed of 350 rpm and a torque of 10,000 ft*lbs.
Responsive to the motor 102 having operating conditions that match
or correspond to one or more sets of designated operating
conditions, the controller 202 may monitor the electrical
characteristics of the motor 102, as measured by the electrical
sensor 208. The controller 202 may examine these electrical
characteristics to determine if one or more peaks or increased
magnitudes in a signature formed by the characteristics occur at a
fault frequency. If such a peak is identified, then the controller
202 may identify damage to the motor 102 and/or coupling 204 and
generate a signal to implement a responsive action, as described
above.
[0045] In another embodiment, the controller 202 may monitor the
electrical characteristics and the operating conditions of the
motor 102 to determine whether the current operating conditions are
the same as or within a designated range of the designated
operating conditions in one or more sets of the designated
operating conditions. Responsive to the motor 102 having operating
conditions that match or correspond to one or more sets of
designated operating conditions, the controller 202 may separate
the electrical characteristics of the motor 102 measured by the
electrical sensor 208 while the motor 102 operated using the
designated operating conditions from the electrical characteristics
measured during the motor 102 operating using other operating
conditions. The controller 202 may examine these electrical
characteristics to determine if one or more peaks or increased
magnitudes in a signature formed by the characteristics occur at a
fault frequency. If such a peak is identified, then the controller
202 may identify damage to the motor 102 and/or coupling 204 and
generate a signal to implement a responsive action, as described
above.
[0046] The designated operating conditions may be determined to be
the same for several vehicle systems 100 and/or motors 102. For
example, the same designated operating conditions may be used for
the same type of motors 102 (e.g., motors having the same
fabrication, number of windings, size, horsepower rating, etc.).
Alternatively, the designated operating conditions may be
individualized for different vehicle systems 100. For example, the
designated operating conditions may be determined separately and
differently for each vehicle system 100, and the designated
operating conditions may be used for the motors 102 of that vehicle
system 100, but not for the motors 102 of other vehicle systems
100. Alternatively, the designated operating conditions may be
individualized for different motors 102. For example, the
designated operating conditions may be determined separately and
differently for each motor 102 in a vehicle system 100, and
different motors 102 in the same vehicle system 100 may use
different designated operating conditions to determine damage to
the motors 102 and/or couplings 204.
[0047] FIG. 10 illustrates a flowchart of one embodiment of a
method 1000 for monitoring a vehicle system 100 and/or a motor 102
of the vehicle system. The method 1000 may be used to monitor the
health of the motor 102 and/or couplings 204, such as to identify a
damaged bearing, raceway, gear, or the like, of the motor 102
and/or couplings 204. In one aspect, the method 1000 may represent
or be used to create a software application that directs operations
of the controller 202, as described above. While the description of
the method 1000 focuses on monitoring a single motor, the method
1000 may be used to concurrently monitor multiple motors.
[0048] At 1002, a determination is made as to whether the vehicle
system and/or motor are operating during a baseline time period. As
described above, the baseline time period includes a duration of
time where the operating conditions of the vehicle system 100
and/or motor 102, and electrical characteristics of the motor 102,
are monitored to identify one or more sets of operating conditions
that yield less noise or otherwise include more clear indications
of motor damage in motor electrical signatures than other operating
conditions.
[0049] If the vehicle system is operating during the baseline time
period, then flow of the method 1000 can proceed toward 1004 to
obtain the operating conditions and electrical characteristics. If
the vehicle system is not operating during the baseline time
period, then flow of the method 1000 can proceed toward 1012.
[0050] At 1004, motor speed(s) of the motor being monitored are
measured. A speed sensor may measure the speeds at which the motor
rotates. These speeds may be stored in the memory of the monitoring
system. At 1006, motor torque(s) generated by the motor are
determined. The torques may be determined based on the voltages
and/or currents demanded by or supplied to the motor 102. At 1008,
electrical characteristics of the current supplied to the motor are
measured. The electrical characteristics are measured and
associated with the operating conditions (e.g., the motor speeds
and torques) occurring when the electrical characteristics are
measured. The electrical characteristics may be stored in the
memory and associated with the operating conditions in the
memory.
[0051] At 1010, one or more electrical signatures of the electrical
characteristics are determined. The signatures may include
frequency domain spectra of the electrical characteristics of the
current supplied to the motor. Different signatures may be
generated for different operating conditions. For example, for
different combinations of motor speed and torque, different
signatures may be generated using the electrical characteristics
that were measured when the motor was operating using the
respective motor speed and torque combination.
[0052] Flow of the method 1000 may return toward 1002 to determine
if the motor and/or vehicle system continue to operate during the
baseline time period or if the baseline time period has expired. If
the baseline time period continues, then additional electrical
characteristics and operating conditions may be monitored to
determine additional electrical signatures associated with
different operating conditions. If the baseline time period has
ended, then the electrical signatures can be examined to determine
the operating conditions to use for monitoring the condition of the
motor and/or vehicle system, as described herein.
[0053] At 1012, one or more sets of designated operating conditions
of the motor are selected based on the electrical signatures that
were determined. The signatures determined at 1010 can be examined
to determine which signatures include less variation or noise at or
near fault frequencies associated with the motor. For example, the
range of magnitudes of electrical signatures at or near the fault
frequencies may be examined for different signatures associated
with different sets of operating conditions. One or more of the
signatures having smaller changes in the magnitudes at or near the
fault frequencies are selected, and the sets of operating
conditions associated with those signatures are selected as
designated operating conditions.
[0054] At 1014, speeds of the motor are monitored. For example, the
speed sensor may measure different speeds at which the motor
rotates to propel the vehicle system. At 1016, torques generated by
the motor are monitored. For example, the controller may determine
the torques based on the current and/or voltage supplied to the
motor. At 1018, a determination is made as to whether a combination
of the motor speed and torque matches one or more sets of
designated operating conditions selected at 1012. A speed and
torque combination may match a set of designated operating
conditions when the motor speed is the same as or within a
designated range (e.g., 1%, 3%, 5%, or the like) of a speed in a
set of designated operating conditions and the torque is the same
as or within the designated range of a torque in the same set of
designated operating conditions. If the motor speed and torque
matches a set of designated operating conditions, then flow of the
method 1000 can proceed toward 1020. At 1020, electrical
characteristics of the motor are measured during operation of the
motor under the designated operating conditions. Alternatively, the
electrical characteristics may be monitored while the motor is
operating using the designated operating conditions and also while
the motor is operating using other operating conditions, and the
electrical characteristics measured while the motor is operating
using the designated operating conditions are examined while other
electrical characteristics are not examined. If, at 1018, the
operating conditions do not match the one or more sets of
designated operating conditions, then flow of the method 1000 may
return toward 1014. For example, the motor speeds and torques can
continue to be monitored to determine if and when the motor
operates using designated operating conditions.
[0055] At 1022, one or more electrical signatures are determined
from the electrical characteristics. The signatures can be
determined using the electrical characteristics of the current
supplied to the motor while the motor operates using one or more
sets of designated operating conditions. The signatures can be
frequency domain spectra of the electrical characteristics.
[0056] At 1024, a determination is made as to whether the
electrical signatures indicate damage to the motor and/or couplings
of the motor to a wheel or axle. The signatures can be examined to
determine if the signatures include one or more peaks at or near
fault frequencies. For example, if a signature includes a peak
(e.g., an increase in the signature by at least a designated
threshold amount, such as a 10%, 20%, 30%, or the like, increase)
at a fault frequency, then the signature may indicate damage to the
motor and/or couplings. As a result, flow of the method 1000 can
proceed toward 1026. Otherwise, flow of the method 1000 can return
toward 1014 for additional monitoring of motor speed and
torque.
[0057] At 1026, one or more responsive actions are implemented. For
example, upon identification of damage to the motor or couplings, a
control signal may be generated by the controller that is used by
the controller to control the tractive efforts and/or retarding
efforts provided by the vehicle system that includes the motor. The
control signal may automatically change the tractive efforts and/or
retarding efforts, such as by slowing down or stopping movement of
the vehicle. Alternatively, the control signal may provide a
notification to an operator of the vehicle (e.g., instructions that
are displayed on a display device) that instructs the operator to
slow down or stop movement of the vehicle. In another embodiment,
the control signal may include an alarm signal that notifies and
warns the operator of the identified impending mechanical failure.
In another example, the output signal may be communicated to a
location disposed off-board of the vehicle system, such as a
dispatch center or a repair center that is remotely located from
the vehicle. In response to receiving the output signal, the
off-board location may schedule a maintenance operation for the
vehicle system, such as a scheduled examination and/or repair to
the motor associated with the impending mechanical failure that is
identified. The off-board location may transmit a responsive signal
to the vehicle system that controls the tractive efforts of the
vehicle system, or instructs an operator of the vehicle system to
change the tractive efforts of the vehicle system, to stop the
vehicle system or cause the vehicle system to travel to a
designated maintenance facility where the motor can be examined
and/or repaired. In one embodiment, the output signal from the
vehicle system may include information related to the maintenance
operation to be performed on the motor, such as a potential
identification of the motor and/or of a bearing or gear that may be
the cause of the impending mechanical failure that is
identified.
[0058] In one embodiment, a method (e.g., for monitoring a
propulsion system of a vehicle system) includes monitoring
operating conditions of the vehicle system, determining whether the
operating conditions of the vehicle system match designated
operating conditions, examining an electrical signature
representative of an electric current supplied to the propulsion
system of the vehicle system responsive to determining that the
operating conditions of the vehicle system that are monitored match
the designated operating conditions, and identifying damage to the
propulsion system of the vehicle system based on the electrical
signature that is examined.
[0059] In one aspect, the operating conditions include a speed at
which a motor of the propulsion system rotates.
[0060] In one aspect, the operating conditions include a torque
generated by a motor of the propulsion system.
[0061] In one aspect, the operating conditions include both a speed
at which a motor of the propulsion system rotates and a torque
generated by the motor.
[0062] In one aspect, the designated operating conditions include a
designated speed at which a motor of the propulsion system
rotates.
[0063] In one aspect, the designated operating conditions include a
designated torque generated by a motor of the propulsion
system.
[0064] In one aspect, the designated operating conditions include
both a designated speed at which a motor of the propulsion system
rotates and a designated torque generated by the motor.
[0065] In one aspect, the electrical signature includes a frequency
domain spectrum of one or more electrical characteristics of the
current supplied to the propulsion system.
[0066] In one aspect, the damage is identified responsive to
determining that the electrical signature includes an increased
magnitude at one or more fault frequencies associated with the
damage to the propulsion system.
[0067] In another embodiment, another method (e.g., for monitoring
a propulsion system of a vehicle system) includes monitoring
operating conditions of the propulsion system of the vehicle system
during a baseline time period, monitoring one or more electrical
characteristics of current supplied to the propulsion system during
the baseline time period, examining one or more electrical
signatures of the propulsion system to identify at least one
electrical signature having reduced variances in magnitude at one
or more frequencies associated with damage to the propulsion
system, and determining one or more sets of designated operating
conditions of the propulsion system based on the one or more
electrical signatures that are examined. The one or more sets of
designated operating conditions are used to determine which of
subsequently monitored electrical characteristics of the current
are to be examined to identify the damage to the propulsion
system.
[0068] In one aspect, the operating conditions include a speed at
which a motor of the propulsion system rotates.
[0069] In one aspect, the operating conditions include a torque
generated by a motor of the propulsion system.
[0070] In one aspect, the operating conditions include both a speed
at which a motor of the propulsion system rotates and a torque
generated by the motor.
[0071] In one aspect, the designated operating conditions include a
designated speed at which a motor of the propulsion system
rotates.
[0072] In one aspect, the designated operating conditions include a
designated torque generated by a motor of the propulsion
system.
[0073] In one aspect, the designated operating conditions include
both a designated speed at which a motor of the propulsion system
rotates and a designated torque generated by the motor.
[0074] In one aspect, the one or more electrical signatures include
a frequency domain spectrum of one or more electrical
characteristics of the current supplied to the propulsion
system.
[0075] In one aspect, the method also includes subsequently
determining whether additional operating conditions of the vehicle
system match the designated operating conditions of at least one of
the sets of the one or more designated operating conditions,
examining an additional electrical signature of the current
supplied to the propulsion system responsive to determining that
the additional operating conditions of the vehicle system match the
designated operating conditions of the at least one of the sets,
and identifying the damage to the propulsion system based on the
additional electrical signature that is examined.
[0076] In another embodiment, a system (e.g., a monitoring system)
includes one or more sensors and a controller. The one or more
sensors are configured to measure operating conditions of a vehicle
system. The controller is configured to determine whether the
operating conditions of the vehicle system match designated
operating conditions. The controller also is configured to examine
an electrical signature representative of an electric current
supplied to a motor of the vehicle system responsive to determining
that the operating conditions of the vehicle system that are
monitored match the designated operating conditions. The controller
also is configured to identify damage to one or more of the motor
of the vehicle system or a mechanical coupling of the motor to one
or more of a wheel or axle of the vehicle system based on the
electrical signature that is examined.
[0077] In one aspect, the operating conditions include a speed at
which the motor rotates.
[0078] In one aspect, the operating conditions include a torque
generated by the motor.
[0079] In one aspect, the operating conditions include both a speed
at which the motor rotates and a torque generated by the motor.
[0080] In one aspect, the designated operating conditions include a
designated speed at which the motor rotates.
[0081] In one aspect, the designated operating conditions include a
designated torque generated by the motor.
[0082] In one aspect, the designated operating conditions include
both a designated speed at which the motor rotates and a designated
torque generated by the motor.
[0083] In one aspect, the electrical signature includes a frequency
domain spectrum of one or more electrical characteristics of the
current supplied to the motor.
[0084] In one aspect, the controller is configured to identify the
damage responsive to determining that the electrical signature
includes an increased magnitude at one or more fault frequencies
associated with the damage to the one or more of the motor or the
mechanical coupling.
[0085] In another embodiment, another system (e.g., a monitoring
system) includes one or more sensors and a controller). The one or
more sensors are configured to measure operating conditions of a
motor of a vehicle system during a baseline time period. The
controller is configured to monitor one or more electrical
characteristics of current supplied to the motor during the
baseline time period, and to examine one or more electrical
signatures of the motor to identify at least one electrical
signature having reduced variances in magnitude at one or more
frequencies associated with damage to one or more of the motor or a
mechanical coupling of the motor to one or more of a wheel or an
axle of the vehicle system. The controller is configured to
determine one or more sets of designated operating conditions of
the motor based on the one or more electrical signatures that are
examined. The one or more sets of designated operating conditions
are used by the controller to determine which of subsequently
monitored electrical characteristics of the current are to be
examined to identify the damage to the one or more of the motor or
the mechanical coupling of the motor.
[0086] In one aspect, the operating conditions include a speed at
which the motor rotates.
[0087] In one aspect, the operating conditions include a torque
generated by the motor.
[0088] In one aspect, the operating conditions include both a speed
at which the motor rotates and a torque generated by the motor.
[0089] In one aspect, the designated operating conditions include a
designated speed at which the motor rotates.
[0090] In one aspect, the designated operating conditions include a
designated torque generated by the motor.
[0091] In one aspect, the designated operating conditions include
both a designated speed at which the motor rotates and a designated
torque generated by the motor.
[0092] In one aspect, the one or more electrical signatures include
a frequency domain spectrum of one or more electrical
characteristics of the current supplied to the motor.
[0093] In one aspect, the controller also is configured to
subsequently determine whether additional operating conditions of
the vehicle system match the designated operating conditions of at
least one of the sets of the one or more designated operating
conditions. The controller also is configured to examine an
additional electrical signature of the current supplied to the
motor responsive to determining that the additional operating
conditions of the vehicle system match the designated operating
conditions of the at least one of the sets and to identify the
damage to the one or more of the motor or the mechanical coupling
of the motor based on the additional electrical signature that is
examined.
[0094] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the invention without departing from its scope. While the
dimensions and types of materials described herein are intended to
define the parameters of the invention, they are by no means
limiting and are exemplary embodiments. Many other embodiments will
be apparent to one of ordinary skill in the art upon reviewing the
above description. The scope of the subject matter described herein
should, therefore, be determined with reference to the appended
clauses, along with the full scope of equivalents to which such
clauses are entitled. In the appended clauses, the terms
"including" and "in which" are used as the plain-English
equivalents of the respective terms "comprising" and "wherein."
Moreover, in the following clauses, the terms "first," "second,"
and "third," etc. are used merely as labels, and are not intended
to impose numerical requirements on their objects. Further, the
limitations of the following clauses are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.112(f), unless and until such clause
limitations expressly use the phrase "means for" followed by a
statement of function void of further structure.
[0095] This written description uses examples to disclose several
embodiments of the invention, including the best mode, and also to
enable any person of ordinary skill in the art to practice the
embodiments disclosed herein, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the subject matter is defined by the clauses,
and may include other examples that occur to one of ordinary skill
in the art. Such other examples are intended to be within the scope
of the clauses if they have structural elements that do not differ
from the literal language of the clauses, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the clauses.
[0096] The foregoing description of certain embodiments of the
disclosed subject matter will be better understood when read in
conjunction with the appended drawings. To the extent that the
figures illustrate diagrams of the functional blocks of various
embodiments, the functional blocks are not necessarily indicative
of the division between hardware circuitry. Thus, for example, one
or more of the functional blocks (for example, processors or
memories) may be implemented in a single piece of hardware (for
example, a general purpose signal processor, microcontroller,
random access memory, hard disk, and the like). Similarly, the
programs may be stand alone programs, may be incorporated as
subroutines in an operating system, may be functions in an
installed software package, and the like. The various embodiments
are not limited to the arrangements and instrumentality shown in
the drawings.
[0097] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Moreover, unless explicitly
stated to the contrary, embodiments "comprising," "including," or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property.
[0098] Since certain changes may be made in the above-described
systems and methods, without departing from the spirit and scope of
the subject matter herein involved, it is intended that all of the
subject matter of the above description or shown in the
accompanying drawings shall be interpreted merely as examples
illustrating the inventive concepts herein and shall not be
construed as limiting the disclosed subject matter.
* * * * *