U.S. patent application number 09/197783 was filed with the patent office on 2002-05-23 for apparatus and method for monitoring shaft cracking or incipient pinion slip in a geared system.
Invention is credited to KLIMAN, GERALD B., REDDY, SURESH BADDAM, SRIBAR, ROK.
Application Number | 20020062194 09/197783 |
Document ID | / |
Family ID | 22730748 |
Filed Date | 2002-05-23 |
United States Patent
Application |
20020062194 |
Kind Code |
A1 |
KLIMAN, GERALD B. ; et
al. |
May 23, 2002 |
APPARATUS AND METHOD FOR MONITORING SHAFT CRACKING OR INCIPIENT
PINION SLIP IN A GEARED SYSTEM
Abstract
A diagnostic technique for monitoring shaft cracking or
incipient pinion slip involves monitoring a shift in a
characteristic natural frequency of an operating system such as a
geared system of a locomotive. The technique involves monitoring a
shift in the characteristic natural frequency or resonance of a
shaft for detecting shaft cracking. The technique also involves
monitoring a shift in the characteristic natural frequency of one
or more assemblies of the operating system which include a pinion
and detecting a shift in the one or more characteristic natural
frequencies of the assemblies. A vibration sensor or measurement of
current changes of a motor of the operating system can be used to
detect vibrations to monitor the characteristic natural
frequencies. Torsional oscillations or measurement of current and
voltage changes of a motor of the operating system, can also be
used to monitor the characteristic natural frequencies.
Inventors: |
KLIMAN, GERALD B.;
(NISKAYUNA, NY) ; REDDY, SURESH BADDAM; (ERIR,
PA) ; SRIBAR, ROK; (MOUNTAIN VIEW, CA) |
Correspondence
Address: |
GENERAL ELECTRIC COMPANY
CRD PATENT DOCKET ROOM 4A59
P O BOX 8
BUILDING K 1 SALAMONE
SCHENECTADY
NY
12301
US
|
Family ID: |
22730748 |
Appl. No.: |
09/197783 |
Filed: |
November 23, 1998 |
Current U.S.
Class: |
702/35 |
Current CPC
Class: |
G01M 13/028 20130101;
G01H 1/003 20130101; G01M 13/021 20130101 |
Class at
Publication: |
702/35 |
International
Class: |
G01B 005/30 |
Claims
1. An apparatus for monitoring shaft cracking or incipient pinion
slip in an operating system, the apparatus comprising: a controller
adapted to determine a characteristic natural frequency of the
operating system at a first time; the controller adapted to
determine the characteristic natural frequency at a second time;
and the controller adapted to compare the characteristic natural
frequency determined at the first time to the characteristic
natural frequency determined at the second time to detect a shift
in the characteristic natural frequency in response to at least one
of shaft cracking and incipient pinion slip.
2. The apparatus according to claim 1, wherein the characteristic
natural frequency is a natural frequency of a shaft of the
operating system.
3. The apparatus according to claim 1, wherein the characteristic
natural frequency is a natural frequency of an assembly of the
operating system.
4. The apparatus according to claim 3, wherein the characteristic
natural frequency is a natural frequency of the assembly comprising
a pinion.
5. The apparatus according to claim 1, wherein the characteristic
natural frequency comprises a first characteristic natural
frequency of a first assembly of the operating system and a second
characteristic natural frequency of a second coupled assembly of
the operating system.
6. The apparatus according to claim 1, wherein the controller is
adapted to determine the characteristic natural frequency in
response to vibration measurements of the operating system.
7. The apparatus according to claim 1, wherein the controller is
adapted to determine the characteristic natural frequency in
response to current measurements of a motor of the operating
system.
8. The apparatus according to claim 1, wherein the controller is
adapted to determine the characteristic natural frequency in
response to torsional oscillation determinations of the operating
system.
9. The apparatus according to claim 1, wherein the controller is
adapted to determine the characteristic natural frequency in
response to current and voltage measurements of a motor of the
operating system.
10. The apparatus according to claim 6, wherein the controller is
adapted to determine the characteristic natural frequency by using
a fast Fourier transform analysis of the vibration
measurements.
11. The apparatus according to claim 1, wherein the operating
system is a geared system.
12. The apparatus according to claim 11, wherein the operating
system is a geared system of a locomotive.
13. An apparatus for monitoring shaft cracking or incipient pinion
slip in an operating system, the apparatus comprising: means for
determining a characteristic natural frequency of the operating
system at a first time; means for determining the characteristic
natural frequency at a second time; and means for comparing the
characteristic natural frequency determined at the first time to
the characteristic natural frequency determined at the second time
to detect a shift in the characteristic natural frequency in
response to at least one of shaft cracking and incipient pinion
slip.
14. An article of manufacture comprising: at least one computer
usable medium having computer readable program code means embodied
therein for causing the monitoring of shaft cracking or incipient
pinion slip in an operating system, the computer readable program
code means in the article of manufacture comprising: computer
readable program code means for determining a characteristic
natural frequency of the operating system at a first time; computer
readable program code means for determining the characteristic
natural frequency at a second time; and computer readable program
means for comparing the characteristic natural frequency determined
at the first time to the characteristic natural frequency
determined at the second time to detect a shift in the
characteristic natural frequency in response to at least one of
shaft cracking and incipient pinion slip.
15. A method for monitoring shaft cracking or incipient pinion slip
in an operating system, the method comprising: determining a
characteristic natural frequency of the operating system at a first
time; determining the characteristic natural frequency at a second
time; and comparing the characteristic natural frequency determined
at the first time to the characteristic natural frequency
determined at the second time to detect a shift in the
characteristic natural frequency in response to at least one of
shaft cracking and incipient pinion slip.
16. The method according to claim 15, wherein the characteristic
natural frequency is a natural frequency of a shaft of the
operating system.
17. The method according to claim 15, wherein the characteristic
natural frequency is a natural frequency of an assembly of the
operating system.
18. The method according to claim 17, wherein the assembly
comprises a pinion.
19. The method according to claim 15, wherein the characteristic
natural frequency comprises a first characteristic natural
frequency of a first assembly of the operating system and a second
characteristic natural frequency of a second coupled assembly of
the operating system.
20. The method according to claim 15, wherein determining the
characteristic natural frequency at the first and second times
comprises measuring vibrations of the operating system.
21. The method according to claim 15, wherein determining the
characteristic natural frequency at the first and second times
comprises measuring current of a motor of the operating system.
22. The method according to claim 15, wherein determining the
characteristic natural frequency at the first and second times
comprises measuring torsional oscillations of the operating
system.
23. The method according to claim 15, wherein determining the
characteristic natural frequency at the first and second times
comprises measuring current and voltage of a motor of the operating
system.
24. The method according to claim 15, wherein determining the
characteristic natural frequency at the first and second times
comprises performing a fast Fourier transform analysis of the
measured current.
25. The method according to claim 15, wherein the operating system
is a geared system.
26. The method according to claim 17, wherein the operating system
is a geared system of a locomotive.
27. At least one program storage device readable by a machine,
tangibly embodying at least one program of instructions executable
by the machine to perform a method of monitoring shaft cracking or
incipient pinion slip in an operating system, the method
comprising; determining a characteristic natural frequency of the
operating system at a first time; determining the characteristic
natural frequency at a second time; and comparing the
characteristic natural frequency determined at the first time to
the characteristic natural frequency determined at the second time
to detect a shift in the characteristic natural frequency in
response to at least one of shaft cracking and incipient pinion
slip.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to shaft cracking and incipient
pinion slip, and more particularly, to monitoring shaft cracking
and incipient pinion slip in an operating system such as a geared
system of a locomotive.
[0002] In a geared system, the motion or torque from one shaft is
transmitted to another shaft by means of direct contact between
toothed wheels or gears. FIG. 1 illustrates one example of a geared
system 10 for propelling a locomotive. Geared system 10 includes an
electric motor 12 having a drive shaft 14 rotatably supported by
bearings 16 which are attached to the locomotive, a rotor 11, a
stator 19 with stator windings 21 and leads 23. Attached to one end
of drive shaft 14 is a pinion 18. Typically, pinion 18 is fitted
and shrunk onto a tapered end 15 of drive shaft 14. Pinion 18
engages a bull gear 20 which attaches to and drives a wheel shaft
22 rotatably supported by bearings 24. The ends of wheel shaft 22
are attached to respective wheels 26 of the locomotive.
[0003] Although electric motor 12 is resiliently supported to the
locomotive, geared system 10 experiences large mechanical
vibrations, e.g., shock loadings due to uneven portions of rails
30. Often, after some period of heavy usage, drive shaft 14 may
crack due to fatigue. Similarly, pinion 18 may slip relative to
drive shaft 14 without any advanced warning so that torque is no
longer transmitted to wheels 26. Such failures can be catastrophic,
and repairs such as removal of electric motor 12, refitting of
pinion 18, or replacement of drive shaft 14, are expensive, labor
intensive, and require that the locomotive be temporarily pulled
from service.
[0004] Therefore, there is a need for an apparatus and method for
low cost, on-line monitoring of an operating geared system in which
the apparatus and method are capable of warning of shaft cracking
or incipient pinion slip.
SUMMARY OF THE INVENTION
[0005] The above-mentioned need is met by the present invention
which relates to diagnostic techniques for monitoring shaft
cracking or incipient pinion slip in an operating system. In one
aspect of the present invention, a method for monitoring shaft
cracking or incipient pinion slip in an operating system includes
the steps of determining a characteristic natural frequency of the
operating system at a first time, determining the characteristic
natural frequency at a second time, and comparing the
characteristic natural frequency determined at the first time to
the characteristic natural frequency determined at the second time
to detect a shift in the characteristic natural frequency in
response to at least one of shaft cracking and incipient pinion
slip.
[0006] For monitoring shaft cracking, the characteristic natural
frequency is a natural frequency of a shaft of the operating
system. For monitoring pinion slip, the characteristic natural
frequency is a natural frequency of an assembly including a pinion
of the operating system or the characteristic natural frequencies
of two coupled assemblies which includes the pinion.
[0007] The steps of determining the characteristic natural
frequency may include measuring vibrations of the operating system,
measuring current of a motor of the operating system, measuring
torsional oscillations of the operating system, or measuring
current and voltage of a motor of the operating system.
Advantageously, the steps of determining the characteristic natural
frequency may include the step of performing a fast Fourier
transform analysis.
[0008] In another aspect of the present invention, an apparatus for
monitoring shaft cracking or incipient pinion slip in an operating
system, includes a controller adapted to determine a characteristic
natural frequency of the operating system at a first time,
determine the characteristic natural frequency at a second time,
and compare the characteristic natural frequency determined at the
first time to the characteristic natural frequency determined at
the second time to detect a shift in the characteristic natural
frequency in response to at least one of shaft cracking and
incipient pinion slip.
[0009] In still another aspect of the present invention, an article
of manufacture comprises at least one computer usable medium having
computer readable program code means embodied therein for causing
the monitoring of shaft cracking or incipient pinion slip in an
operating system. The computer readable program code means in the
article of manufacture comprises computer readable program code
means for determining a characteristic natural frequency of the
operating system at a first time, determining the characteristic
natural frequency at a second time, and comparing the
characteristic natural frequency determined at the first time to
the characteristic natural frequency determined at the second time
to detect a shift in the characteristic natural frequency in
response to at least one of shaft cracking and incipient pinion
slip.
[0010] In yet another aspect of the present invention, at least one
program storage device readable by a machine, tangibly embodying at
least one program of instructions executable by the machine,
performs a method for monitoring shaft cracking or incipient pinion
slip in an operating system, as noted above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a side elevation view, in part section, of a
geared system and control system of a locomotive including a
vibration sensor positioned in accordance with one embodiment of
the present invention;
[0012] FIG. 2 is a diagrammatic illustration of one embodiment of
an apparatus for monitoring shaft cracking or incipient pinion slip
during the operation of the geared system shown in FIG. 1;
[0013] FIG. 3 is a graph of a signal representing vibrations or
displacements over time during the operation of the geared system
shown in FIG. 1;
[0014] FIG. 4 is a graph of the frequency components of the signal,
shown in FIG. 3, as a result of a fast Fourier transform
analysis;
[0015] FIG. 5 is a graph of the change or shift, over time, in the
characteristic natural frequency of the drive shaft shown in FIG. 1
during operation;
[0016] FIG. 6 is a diagrammatic illustration of an alternative
embodiment of an apparatus for monitoring shaft cracking or
incipient pinion slip during the operation of the geared system
shown in FIG. 1;
[0017] FIG. 7 is a diagrammatic illustration of an alternative
embodiment of an apparatus for monitoring shaft cracking or
incipient pinion slip during the operation of the geared system
shown in FIG. 1;
[0018] FIG. 8 is a graph of a signal over time representing the
current supplied to the motor of the geared system shown in FIG.
1;
[0019] FIG. 9 is a graph of the frequency components of the signal,
shown in FIG. 8, as a result of a fast Fourier transform
analysis;
[0020] FIG. 10 is a partial diagrammatic illustration of still
another alternative embodiment of an apparatus for monitoring shaft
cracking or incipient pinion slip during the operation of the
geared system, shown in FIG. 1;
[0021] FIG. 11 is a partial diagrammatic illustration of yet
another alternative embodiment of an apparatus for monitoring shaft
cracking or incipient pinion slip during the operation of the
geared system, shown in FIG. 1, in which the motor is an AC motor;
and
[0022] FIG. 12 is a graph of a signal representing the alternating
current supplied over time to an AC motor of the geared system,
shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides an on-line diagnostic
technique for monitoring shaft cracking or incipient pinion slip in
an operating system 10 (FIG. 1) such as a geared system for
propelling a locomotive. As discussed in greater detail below,
shaft cracking is monitored by observing a shift in the
characteristic natural frequency or resonance of drive shaft 14
(due to lateral oscillations or torsional oscillations) over time.
Incipient pinion slip is monitored by observing a shift (due to
lateral oscillations or torsional oscillations) over time in the
characteristic natural frequency or frequencies of one or more
assemblies of the geared system due to the coupling between a
pinion and a drive shaft.
[0024] With respect to shaft cracking, drive shaft 14 has a natural
frequency or resonance determined, to a first order, by the
distance between its bearings 16, the stiffness of the drive shaft,
and the mass of the drive shaft and rotor. To a lesser extent, the
fit or tolerance of the bearings, as well as pinion 18, may also
influence the characteristic natural frequency of the shaft. If
there is a fracture or significant crack in the shaft, the
stiffness changes resulting in a change or shift in the
characteristic natural frequency of the shaft (due to lateral
oscillations or torsional oscillations). The specific
characteristic natural frequency of an intact shaft to be observed
and monitored can be initially determined by simulating an analytic
model or by testing a physical model.
[0025] FIG. 2 diagrammatically illustrates one embodiment of an
apparatus 40 for monitoring shaft cracking in the geared system 10
(FIG. 1). Apparatus 40 includes a vibration sensor 42 such as an
accelerometer mounted to one of bearings 16 (FIG. 1) for monitoring
vibrations (lateral oscillations) occurring in geared system 10
during operation. Alternatively, vibration sensor 42 may be mounted
on stator 19 of electric motor 12 (FIG. 1).
[0026] The output signal from vibration sensor 42 is a composite or
resultant signal of the many vibrations which occur in geared
system 10 during operation. The vibrations or displacements of
geared system 10 over time can be represented in graphical form, as
shown in FIG. 3. In this exemplary embodiment, the output signal
from vibration sensor 42 is passed through a signal conditioner 44,
an amplifier 46, an antialiasing filter 48, and an analog to
digital converter 50.
[0027] A computer 52 receives the resultant signal from analog to
digital converter 50 and determines the various characteristic
natural frequency components that make up the resultant signal. In
one embodiment, the determination is made using fast Fourier
transform (FFT) analysis, for example. Suitable computer software
programs are readily available for performing an FFT analysis of
the resultant output signal to determine the characteristic natural
frequency components that make up the resultant signal. FIG. 4
illustrates the result of the FFT analysis and characteristic
natural frequency Fs of drive shaft 14.
[0028] Characteristic natural frequency Fs is then monitored and
tracked over time, e.g., days, weeks or months. FIG. 5 illustrates
the results of the tracking of characteristic natural frequency Fs
over time. For example, computer 52 compares a first determination
of characteristic natural frequency Fs to a second later
determination of characteristic natural frequency Fs to detect a
shift in the characteristic natural frequency Fs in response to the
initial stage of shaft cracking or further propagation of one or
more cracks. In this illustrated example, after week 4 the
characteristic natural frequency of the drive shaft is observed to
increase, which may be on the order of only a few percent, to
indicate the beginning of a crack or further propagation of one or
more cracks in the shaft. If the crack or cracks continue to grow,
failure may occur, e.g., as observed between week 8 and week 9 of
FIG. 5. In addition, a determination of the magnitude of the crack
in the shaft can be determined based on the magnitude of the shift
by comparison to analytical or physical model determinations.
[0029] FIG. 6 diagrammatically illustrates an alternative apparatus
60 for detecting displacements or vibrations of geared system 10
and monitoring the characteristic natural frequencies of geared
system 10. In this illustrated embodiment, apparatus 60 comprises
an vibration sensor 62, a signal conditioner 64, and a spectrum
analyzer 66 which selects the characteristic natural frequency
components of the resultant signal from the vibration sensors
during operation of geared system 10.
[0030] Apparatuses 40 (FIG. 2) and 60 (FIG. 6) are also desirably
operable to monitor incipient pinion slip due to the loss or
decrease in the area of contact between pinion 18 (FIG. 1) and
drive shaft 14 (FIG. 1). In another aspect of the present invention
and with reference to FIG. 1, the characteristic natural frequency
monitored corresponds to an assembly which includes pinion 18,
e.g., pinion 18 and drive shaft 14. As with shaft cracking, a shift
in characteristic natural frequency of this assembly can be used to
indicate a reduction in the area of contact between the pinion 18
and drive shaft 14.
[0031] Since the characteristic natural frequency of the assembly
of pinion 18 and drive shaft 14 would be close to the
characteristic natural frequency of drive shaft 14 (pinion 18
typically has a relatively small mass compared to drive shaft 14),
in another aspect of the present invention, desirably, two
independent coupled assemblies of geared system 10 are utilized to
monitor incipient pinion slip.
[0032] For example, with reference still to FIG. 1, a first
assembly 17 includes electric motor 12, drive shaft 14, bearings
16, and pinion 18 which will have a first independent
characteristic natural frequency FA1 (FIG. 4). In addition, a
second assembly 27 includes wheel shaft 22, bearings 24, bull gear
20, and wheels 26 which will have a second independent
characteristic natural frequency FA2 (FIG. 4) which can be
monitored by the same sensor, as shown in FIGS. 1 and 4, or by a
separate sensor (not shown). While the coupling between the teeth
of pinion 18 and the teeth of bull gear 20 is generally constant,
the coupling between the two assemblies 17 and 27 will both change
or shift with a change in the stiffness of the fit between pinion
18 and drive shaft 14.
[0033] If the contact between the pinion and the shaft extends over
the maximum possible contact area, the coupling should be
reasonably stiff. However, if there is substantially less contact
area, pinion 18 becomes more flexible with respect to drive shaft
14, so that the stiffness of the coupling will be less with
consequently a shift in both the individual characteristic natural
frequencies of assembly 17 and assembly 27. Thus, by determining
and monitoring the characteristic natural frequencies of the two
above-noted assemblies, the monitoring of pinion slip is
essentially a function of the entire mass of the geared systems. As
with shaft cracking, the characteristic natural frequencies of the
two assemblies can be initially predetermined by an analytic model
or by testing a physical model.
[0034] By tracking the shift in the characteristic natural
frequencies of both these two assemblies, incipient pinion slip can
be detected. In addition, a determination of the loss of contact
area between the drive shaft and the pinion can be determined based
on the magnitude of the shift by comparison to the analytical or
physical model. Loss of contact area, in turn, implies reduced
capability of the fit to sustain high torques, hence, increased
likelihood of pinion slip under heavy loading.
[0035] In another aspect of the present invention electric motor 12
may be employed for monitoring the desired characteristic natural
frequencies instead of vibration sensors. Vibration sensors, while
suitable, are delicate devices and require cables which can become
loose and have a limited operable life. For example, lateral
oscillations of the motor (e.g., radial motions) due to the
vibrations of the geared system during operation cause the air gap
between the rotor 11 and the stator 19 (FIG. 1) to vary. This
effect causes a change in the magnetic flux, which results in small
changes in the flow of current through motor windings 21. FIG. 7
diagrammatically illustrates an apparatus 70 for detecting
characteristic natural frequencies of geared system 10 shown in
FIG. 1 via measurement of the current to motor 12 by a current
sensor 72 which in one embodiment is coupled to one of leads 23 of
motor 12.
[0036] The current to a DC motor over time, while generally
constant also contains small variations in the current due to
lateral oscillations of the motor, as illustrated in FIG. 8. The
small variations in the current can be detected by current sensor
72, e.g., a shunt having a low resistance. Alternatively, a current
sensor having sensor windings (not shown) which wrap around
electrical current lead 23 (FIG. 1) to the motor can be employed.
For example, the changing current to the motor will cause a
changing current in the sensor windings. A signal can be applied to
the sensor windings to reduce the changing current in the sensor
windings to zero. The signal applied to the sensor windings of the
current sensor will correspond to the variations in the current to
the motor. Such current measuring sensors are available from LEM
Instruments, Inc. of Torrance, Calif., for example.
[0037] In one embodiment, the output signal from current sensor 72
is passed through a signal conditioner 74, an amplifier 76, an
antialiasing filter 78, and an analog to digital converter 80. The
resultant signal from analog to digital converter 80 is then
supplied to a computer 82 which determines the various
characteristic natural frequency components that make up the
resultant signal, as illustrated in FIG. 9. In one embodiment, the
computer analysis includes a fast Fourier transform of the
resultant signal from the analog to digital converter. As discussed
above, one or more characteristic natural frequencies can be
monitored to detect a shift in response to shaft cracking or
incipient pinion slip.
[0038] In still another aspect of the invention, the torque of
electric motor 12 (FIG. 1) is utilized for determining torsional
oscillations of the geared system 10 which can also be correlated
to various characteristic natural frequencies of drive shaft 14
(FIG. 1) and the coupling between pinion 18 (FIG. 1) and drive
shaft 14 (FIG. 1). For example, with DC motors, calculation of the
torque is a function of the voltage and the current. As shown in
FIG. 10, a voltage sensor 92 and a current sensor 94 can be
operably connected to the electrical power leads to motor 12 (FIG.
1). The output signals may be combined to determine the torque
which can then be processed as described above with regard to
apparatuses 40, 60, and 70.
[0039] For AC motors, two voltage sensors 102 and 103, and two
current sensors 104 and 105 (FIG. 11), are operably connected to
electrical power leads 23 of an AC motor 12 of geared system 10
(FIG. 1). The output signals may be operably combined to determine
the torque which can be processed, as described above with regard
to apparatuses 40, 60, and 70. In addition, in the case of an AC
motor, the AC current of sensor 104 or 105 will modulate, as
illustrated in FIG. 12. This modulation can be detected by an
amplitude demodulation detector (not shown) to select out the
varying signal which, in turn, can be FFT analyzed to select out
the component characteristic natural frequencies and processed, as
described above, with reference to apparatuses 40, 60, and 70.
[0040] The above noted apparatuses may be embodied in or combined
with a controller or computing environment 200 such as the
locomotive's elaborate control system depicted in FIG. 1. Computing
environment 200 includes, for instance, at least one central
processing unit 202, a memory or main storage 204, and one or more
input/output devices 206. Computing environment 200 may be provided
as a single system environment or multiple system environment for
running an operating system.
[0041] As is known, central processing unit 202 is the controlling
center and provides the sequencing and processing facilities for
instruction execution, interruption action, timing functions,
initial program loading, and other machine related functions. The
central processing unit 202 executes at least one operating system,
which, as known, is used to control the operation of computing
processing unit 202 by controlling the execution of other programs,
controlling communication with peripheral devices and controlling
use of the computer resources.
[0042] Central processing unit 202 is coupled to main storage 204,
which is directly addressable and provides for high speed
processing of data by central processing unit 202. Main storage may
be either physically integrated with the CPU or constructed in
stand alone units. Desirably, main storage 204 may store
predetermined characteristic natural frequencies of one or more
shafts in the operating system, and one or more assemblies of the
geared system, which can be used in selecting out and monitoring
the actual characteristic natural frequencies of the operating
system, as well as determining the magnitude of a crack or pinion
slip.
[0043] Main storage 204 is also coupled to one or more input/output
devices 206. These devices include, for instance, keyboards,
communications controllers, teleprocessing devices, printers,
magnetic storage media (e.g., tape cartridges or disks), optical
storage media (e.g., CD-ROMs), direct access storage devices, and
sensor-based equipment (e.g., vibration sensors 42, current sensors
72, 94,104, and 105, and voltage sensors 92, 102, and 103). Data is
transferred from main storage 204 to input/output devices 206, and
from the input/output devices back to main storage 204.
[0044] From the present description, computer readable program code
means for use in computing environment 200 and for implementing the
diagnostic techniques of the present invention may be readily
programmed by those skilled in the art and stored on the
above-noted storage media or devices, or imbedded in an integrated
circuit. The technique may be fully automated or require manual
input of various parameters prior to undertaking a diagnostic
procedure.
[0045] It will also be appreciated by those skilled in the art that
measurements from the vibration sensors, current sensors and
voltage sensors may be made at periodic intervals while the geared
system of the locomotive is operating under a load. This can be
downloaded and processed remotely, or alternatively, the
measurement processed onboard and, if a frequency change or phase
shift is detected, a warning can be issued to the engineer. If the
measurements are to be stored on the locomotive, desirably an FFT
analysis is performed to reduce the amount of data to be stored. In
addition, from the present description, it will be appreciated that
the present invention may be applied to monitoring shaft cracking
and incipient slip of each motor-driven wheel assembly of the
locomotive.
[0046] While only certain preferred features of the invention have
been illustrated and described herein, many modifications and
changes will occur to those skilled in the art. It is, therefore,
to be understood that the appended claims are intended to cover all
such modifications and changes as fall within the true spirit of
the invention.
* * * * *