Comparison and Analysis of EMC Performance under No-load and Full-load Conditions of Low-voltage DC Motors

This paper conducted EMI tests based on the actual load conditions using the independently developed nonmetallic loading equipment for low-voltage DC motors. The EMI characteristics of low-voltage DC motors under rated load and no-load conditions were studied. It was found that the test results under load conditions and no-load conditions were significantly different. Especially for brushed low-voltage DC motors, the interference frequency is related to the motor speed and the number of commutators, and commutation sparks are the main cause of electromagnetic interference problems for brushed low-voltage DC motors. Therefore, in order to better simulate the real vehicle conditions, when conducting electromagnetic compatibility tests for low-voltage DC motors, loading conditions should be adopted, and full-band continuous limits should be used.