I have a Carrier RTU 48TJE012-521 208/230 3ph that I can't seem to find the reason why one of the comp. contactors chatter so bad it will eventually brake apart like the other one did when I arrived on the first call to this unit. but when I remove the 3ph comp. wiring from the comp. and power the rtu back up, that contactor pulls in and is fine (no more excessive chatting). I have the same ohms across the three terminal and nothing to ground and when it does run shortly before the contactor chatters badly I'm pulling about the same amp as the other comp. What would make that contactor chatter so excessive that it will eventually brake apart. Any ideas?

J