JM1 series plastic case circuit breaker for locomotive (hereinafter referred to as circuit breaker) is suitable for circuits with AC 50Hz/60Hz, rated working voltage of AC690V and below; DC rated voltage of 250V and below, and rated current up to 800A. The circuit breaker has overload, short circuit and undervoltage protection functions. Circuit breakers are generally used for power distribution protection, and circuit breakers with rated current In≤400A can also be used for motor protection, and perform infrequent start and stop operations on the motor.

The circuit breaker is suitable for land use as well as marine use, and has the ability to withstand humidity, salt spray, mold and the normal vibration of the ship. When used in ships, the normal ambient temperature is -25°C ~ +45°C, and the products comply with IEC92 "Marine Electrical Equipment" and GB/T3783 "Basic Requirements for Marine Low-voltage Electrical Appliances", GB/T14048.2 "Low-voltage Switchgear and Control Equipment No. 1". Part 2: Relevant regulations on circuit breakers.