(1) For the polarity inspection of shunt winding, separately excited winding, series winding of series winding DC motor and compound winding of compound winding DC motor, the poles can be connected in series, and then the polarity can be measured in the middle of pole shoe with compass through DC power supply, and the polarity can be determined by the compass direction after several times. The polarity of series winding and parallel winding of differential compound excitation DC motor is opposite, while that of compound excitation DC motor is the same. When checking the polarity of a certain winding, the other windings should be disconnected, otherwise the accuracy of the test will also be affected. The input voltage shall make the DC current ensure that the magnetic field of the pole has enough ability to attract the compass. 

(2) The polarity of the commutating pole and the rotation direction of the armature of the main pole shall conform to the following relations: DC motor: main pole N → commutating pole n → main pole S; DC generator: main pole N → commutating pole s → main pole S → commutating pole n. When testing the polarity of the commutation pole, the method is the same as that of testing the main pole. The main pole and compensation winding should be disconnected to prevent inaccurate measurement. For the commutation winding with less turn and large section, the current shall be larger (not exceeding the rated value). For the odd commutation pole, it can be assumed that the same test and inspection can be carried out for the even number without pole missing. 

(3) Check the polarity of compensation winding is the same as check the polarity of commutating pole. To disconnect the commutating pole and the main pole winding, since the compensation winding is embedded in the main pole shoe, the polarity of the compensation winding should be measured on the commutating magnet. 

Qingdao AIP Intelligent Instrument Co., Ltd. focus on motor testing and provide one-stop motor testing solution.