3 phase 208V 5hp(approx 30 years old), each time we reset the o/l, upon start up, motor buzzes/hums for up to 30 secs, then trips the o/l.

didn't have time to check the voltage at the starter to see if it was dirty contacts.

Spend more time and energy diagnosing this, or just replace the motor as the customer insists?

edit: spelling

[This message has been edited by Sandro (edited 11-01-2006).]