System and method for predicting mechanical failures in machinery driven by an induction motor
First Claim
1. A system for detecting mechanical disturbances in machinery driven by an induction motor, said system comprising:
- a current sensor monitoring current in at least one phase of the motor and transmitting a corresponding current signal;
a voltage sensor monitoring voltage in said phase of the motor and transmitting a corresponding voltage signal;
a pulse generator receiving said current and voltage signals and transmitting a pulsed signal comprising pulses having leading and trailing edges corresponding to changes in polarity of said current and voltage signals;
a processor receiving and processing said pulsed signal to determine motor torque.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and method for predicting mechanical failures in machinery driven by induction motors by using the motor as a diagnostic tool to detect present mechanical disturbances. The motor is monitored during operation to avoid down-time. The motor'"'"'s torque fluctuations are used as an indicator of early-stage mechanical failures in the machinery. The motor'"'"'s torque fluctuations are determined using indirect sensing techniques that are less expensive and less intrusive than previously known. More specifically, torque is derived from easily and inexpensively measurable parameters, such as motor slip and phase angle. Current operation is compared to known normal operation. Variations of the motor'"'"'s characteristics from the known baseline indicate an actual or approaching mechanical failure. “Experimental Fractals” are disclosed that visually represent a current state of the monitored machinery and allow for visual comparison to a baseline for detection of mechanical failures. Future failures are forecasted by extrapolating a derived trend.
24 Citations
27 Claims
-
1. A system for detecting mechanical disturbances in machinery driven by an induction motor, said system comprising:
-
a current sensor monitoring current in at least one phase of the motor and transmitting a corresponding current signal;
a voltage sensor monitoring voltage in said phase of the motor and transmitting a corresponding voltage signal;
a pulse generator receiving said current and voltage signals and transmitting a pulsed signal comprising pulses having leading and trailing edges corresponding to changes in polarity of said current and voltage signals;
a processor receiving and processing said pulsed signal to determine motor torque. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method for detecting mechanical disturbances in machinery driven by an induction motor, said method comprising:
-
monitoring torque of the motor during operation of the machinery;
developing an operating profile of motor torque reflecting motor torque during operation of the machinery;
comparing the operating profile to a reference profile of motor torque reflecting motor torque during normal operation of the machinery to identify a deviation; and
signaling a mechanical failure of the machinery responsive to identification of said deviation. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
-
25. A method for detecting mechanical failures in machinery driven by an induction motor, said method comprising:
-
determining motor torque for a plurality of angular positions of a rotor; and
creating an experimental fractal representing a current state of the monitored machinery, said experimental fractal relating a plurality of torque values to said plurality of angular positions of said rotor. - View Dependent Claims (26, 27)
-
Specification