July 01, 2005
11 Motor Testing and CBM
Current Testing
What is the value of current testing? Can it be an effective analysis tool by itself?
VP, Electrical Reliability Group
T-Solutions, Inc.
Current Testing
What is the value of current testing? Can it be an effective analysis tool by itself?
Current testing, by itself, can only truly provide a handful of answers:
1. Approximate loading of equipment;
2. Rotor/Load issues with an analog meter;
3. Loss of a phase
In each case, the current reading will only show severe consequences. Combined with voltage testing, however, a more accurate picture can be identified.
For example: Motor Load = (Amps measured/Amps nameplate) x (Volts measured/Volts nameplate)
In addition, if a motor has a severe current unbalance, but a balanced voltage, then you can identify that the motor winding and cabling should be tested. This could also be an indication of a power factor issue.
However, when you then perform an FFT analysis of motor current, then you have the opportunity to identify motor and driven load problems. We will cover that discussion next.
