METHOD AND APPARATUS ANALYZING AND MONITORING THE PERFORMANCE AND OPERATION OF MACHINES AND PROCESSES DRIVEN BY ELECTRICAL MOTORS

• US 3,839,628 A
• Filed: 08/09/1972
• Issued: 10/01/1974
• Est. Priority Date: 08/09/1972
• Status: Expired due to Term

• Current Assignee: Leonard J. Higgins, Rajendran Ramachandran, Richard Jay Murphy
• Original Assignee: Leonard J. Higgins, Rajendran Ramachandran, Richard Jay Murphy
• Inventors: Higgins, Leonard J., Murphy, Richard Jay, Ramachandran, Rajendran
• Primary Examiner(s): Morrison, Malcolm A.
• Assistant Examiner(s): Wise, Edward J.
• Application Number:
  US05/279,090
• Time in Patent Office: 783 Days
• Field of Search: 73/133,104 235/151.3,151.1,92PD,92QC 324/71,76,142 83/72,74,75,76
• US Class Current: 702/60
• CPC Class Codes: E21C 35/24 Remote control specially adapted for machines for slitting or completely freeing the mineral control in general G05
• CPC Class Codes: G01L 3/24 Devices for determining the value of power, e.g. by measuring and simultaneously multiplying the values of torque and revolutions per unit of time, by multiplying the values of tractive or propulsive force and velocity

Abstract

The specifications and drawings disclose a novel method and apparatus for monitoring the operation of machines and processes driven by electric motors. The true power applied to the motor during an operating cycle is measured and changes in this power relative to a standard are correlated with specific operating parameters.

Claims

1. A method of determining the characteristics signature of a machine driven by electric motor including the steps:

measuring the electric power applied to the drive motor during a standard operating cycle of the machine;

storing the information with respect to the frequency spectrum distribution of power applied to the motor during standard operating cycle;

changing one or more of the machine operating parameters required for standard operation;

measuring the power applied to the drive motor during an operating cycle in which said one or more parameters has been varied;

storing the information with respect of the frequency spectrum distribution of power applied to the motor during the operating cycle in which one or more parameters has been varied;

comparing the information concerning frequency spectrum distribution of power for a standard operating cycle with the information concerning frequency spectrum distribution of power for an operating cycle in which said one or more parameters has been varied;

determining from the comparing step components of power which exhibit relatively small changes during the operating cycle in which one or more parameters has been varied as compared with the standard operating cycle; and

determining from the comparing step components of power which exhibit relatively large changes during the operating cycle in which one or more parameters has been varied as compared with the standard operating cycle.

2. A method for monitoring the operation of a machine driven by an electric motor, comprising the steps:

measuring the power applied to the motor during an operating cycle of the machine;

detecting a first component of said power applied to the motor during the operating cycle;

detecting a second component of said power applied to the motor during the operating cycle; and

comparing first and second components to detect changes in the relative magnitudes of said first and second components which exceed a predetermined amount.

3. A method for determining the characteristics signature of a machine or process driven by an electric motor, as in claim 2, wherein said comparing step includes comparing the frequency spectrum distribution of power components for the operating cycle in which one or more parameters has been varied with the frequency spectrum distribution of power components for the standard operating cycle.

4. Apparatus for monitoring of a machine or process driven by an electric motor comprising in combination:

means for measuring the power applied to the motor producing an output signal indicative of the applied power;

a first narrow, band-pass filter means coupled to receive said output signal and produce a signal output proportional to the magnitude of a component of applied motor power which changes relatively slightly with change in a machine operating parameter;

a second narrow, band-pass filter means coupled to receive said output signal and produce a signal output proportional to the magnitude of a component of applied motor power which changes relatively greatly with a change in said machine operating parameter;

means for comparing the output signals of said first and second band-pass filters; and

means for detecting when the difference in said filter outputs exceeds a predetermined amount.