Sorry, I am not good at reading long sentences - by the time I reach the end, the begining is gone! I have read this so many times - but still not very clear as to what motor you use - AC or DC ? And what is this 110VDC stuff ?


sorry my english not good.

"to what motor you use - AC or DC ?"

My motors are 3-ph 480V AC . This motor is driven by its 110VDC(coil rating) 3-ph contactor . I have a relay onboard my 8051 which make/break 110VDC power to the contactor coil ,which in term ON/OFF the Motors. But the Contactors are external to my controller just adjacent to the controller . The motors(grinders) are located 10meter away my controller .

I am also monitoring the GRINDER motor thermal Relay
using a logic 24VDC .This mean if Motor= cool then thermal relay is not open and 24V logic is provided to my MIcrocontroller so motor shouldnt be disabled .

I am surprise if 3-ph CONTACTORS(110VDC coil) which are adjacent to controller and doing ON/OFF my 3-ph motors creating problem?

Thanks/