MOTOR ONLINE/OFFLINE TESTING
Testing both dynamically (rotor) and statically (stator) of the motor will allow for planning of your maintenance based on current condition. Resistance, impedance, inductance, and rotor bars will be tested and trended.
One of the reasons of performing the MCA (motor circuit analysis) is to determine if a correlation exist between the RBPF (rotor bar pass frequency) and static motor conditions.
A test, the rotor re-positioning test, will determine if there is a rotor problem, which will be shown in the vibration spectrum in the report you would receive.
The MCA should be trended annually on all equipment as to locate and correct the following:
Resistance unbalance: Shorten motor life due to heating of terminals.
Impedance & Inductance: Winding contamination/overheating.
Phase Angle: Verifies winding shorts.
Current/Frequency: Verifies winding shorts.
Insulation Resistance: Poor insulation to ground