Possessing the guarding function against overload, under-voltage and phase failure; 1. This product applies to 50Hz380V14~190KW 3-phase asynchronous motor's infrequently self-couplingstep-down start;2. Steel plate welded shell with plastic-sprayed surface;3. Inside mounted auto-transformer, AC contactor thermal relay, time-relay, intermediate relay, fuser and indicator etc;4. Possessing the guarding function against overloadunder-voltage and phase failure;5. Steelpipe and cable wiring; 6. Can be customized according to user's requirements.7. Suitable for GB3836-2000IEC60079, GB12476.1-2000IEC61241 standard request.