Motor Current Analysis

Measurements of a high-resolution frequency spectrum of an induction motors input current provide a good indication of the rotor bars’ condition. In loaded machines, by detecting the amplitude modulation induced by the torque variations that occur whenever a pole of the rotating magnetic field passes by the defective rotor bar (at 2Xslip frequency in a 2-pole motor), detection of rotor bar problems can be established from sidebands analysis of the 50/60 Hz center frequency.

RITEC uses state-of-the-art instrumentation to collect high-resolution data by placing one phase of the motor controller output inside a current clamp.