US 2019/0101436 A1 · Method and Apparatus for Online Condition Monitoring of Variable Speed Motor Applications

Abstract

The subject matter disclosed herein describes a method and system to monitor and identify vibrations in a rotational mechanical system. Various fault conditions in a rotating machine operating at variable speeds may be identified, at least in part, by identifying the multiple of the fundamental frequency, or order, at which the vibration occurs. The orders of vibration present in a measured vibration signal may be determined by finding an order spectrum of a measured vibration signal in the position domain. A fault vector is generated from the order spectrum that identifies the magnitude of each order of vibration present in the measured vibration signal. The fault vector may be plotted on a radar chart to provide a visual indication of the type of fault present in the mechanical system. Evaluation models for each fault determines a probability and magnitude for each fault condition being present in the sampled vibration signal.

Claims20

Dependent claims

A method for monitoring an operating condition of a motor with a motor drive operatively connected to control operation of the motor, the method comprising the steps of:

periodically sampling a first feedback signal at a sampling frequency, wherein the first feedback signal includes data corresponding to the operating condition of the motor;
periodically sampling a velocity feedback signal at the sampling frequency, wherein the velocity feedback signal corresponds to an angular velocity of the motor;
generating a fault vector for the first feedback signal as a function of the first feedback signal and of the velocity feedback signal, wherein the fault vector includes a magnitude of harmonic content present in the first feedback signal at each of a plurality of multiples of the angular velocity of the motor;
generating a feature vector from the fault vector, wherein the feature vector includes a plurality of values identifying how close the fault vector corresponds to an ideal fault vector;
and
identifying a fault condition present in the motor as a function of the feature vector.

3 more elements

A system for monitoring an operating condition of a motor, the system comprising:

a position sensor operatively connected to the motor, wherein the position sensor generates a position feedback signal corresponding to an angular position of the motor;
a motor drive operatively connected to the motor to control operation of the motor, the motor drive including:
a feedback circuit operatively connected to the position sensor to receive the position feedback signal;
a processor operative to:
periodically sample the position feedback signal,
generate a velocity feedback signal corresponding to an angular velocity of the motor as a function of the position feedback signal,
periodically sample a monitored feedback signal, wherein the monitored feedback signal includes data corresponding to the operating condition of the motor,
generate a fault vector for the monitored feedback signal as a function of the monitored feedback signal and of the velocity feedback signal, wherein the fault vector includes a magnitude of harmonic content present in the monitored feedback signal for at least one multiple of the angular velocity of the motor, and
identify a fault condition present in the motor as a function of the fault vector, wherein the processor is operative to perform each of the steps in real time while the motor drive is controlling operation of the motor.

6 more elements

Dependencies are inferred from the claim text.

Method and Apparatus for Online Condition Monitoring of Variable Speed Motor Applications

Life of this patent

Method and Apparatus for Online Condition Monitoring of Variable Speed Motor Applications

Life of this patent

Abstract

Claims20