Patent ID: 9176193
Filing Date: 2015-11-03
Classification: G01R

Abstract:
1. A method for monitoring a permanent magnet motor, wherein the permanent magnet motor includes a stator having a plurality of coils that share a common node; a first electrical lead, a second electrical lead, and a third electrical lead, all of which are wired to the plurality of coils and are adapted for connection to a polyphase power source; a rotor having a plurality of permanent magnets providing a plurality of magnetic fields; and a rotatable shaft supporting the rotor within the stator; the method comprising: wiring a first resistor, a second resistor, and a third resistor respectively to the first electrical lead, the second electrical lead, and the third electrical lead, wherein the first resistor, the second resistor and the third resistor share a reference node; energizing the permanent magnet motor via the polyphase power source; sensing a differential electrical signal between the reference node and the common node; detecting an imbalance of the plurality of magnetic fields based on the differential electrical signal; and defining an acceptable range of the differential electrical signal, wherein the differential electrical signal being beyond the acceptable range indicates that the plurality of magnetic fields are appreciably imbalanced.