Motor Circuit Analysis (MCA™) is a de-energized test method and the test can be initiated from the Motor Control Center (MCC) or directly at the motor. The advantage to testing from the MCC is the entire motor system, including the connections and cables between the test point and the motor, is evaluated.
ALL-TEST PRO MCA™ instruments apply a low voltage, non-destructive AC signal through the motor windings and measure the response to these signals. Winding faults are indicated by variances in the response to the applied signal through the windings. These variances cause unbalances in the measured response to the applied signal. Therefore, when testing 3-phase equipment such as motors, generators, or transformers the response of each phase is compared to the other two. When testing single phase devices or DC motors then the winding is compared to itself or compared to a like single phase device or a like DC motor.
ALL-TEST PRO MCA™ test instruments measure the phase angle (Fi), the current/frequency response (I/F), the impedance (Z) and depending upon the instrument, the resistance (R) and the inductance (L) of each winding. The unbalances of these measurements are compared and simple rules are used to determine the condition of the device under test. Moreover, each instrument will perform an insulation to ground test.