Davebones
Senior Member
- Location
- North Of Tampa Fl
Found a 400 amp feed to a controller cabinet tripped last week . Operator's claim the test stand had not been ran in over a week . We megged the feeder to to the controller all ok . We found the feeder to the 150 HP motor megged 0.03 Meg Ohms . Put some lights on the motor over the weekend to see if it was just moisture in the windings . We megged the motor this morning and had 6 Meg Ohms to ground . Phase to phase measured 1.2 ohms each A,B,C . When we tryed to run the motor we immediately tripped the 400 amp feed plus the 1600 amp main for that section . We pulled the motor leads apart and measured the T-leads nothing indicates a short . Phases the same in ohm readings . One winding reads the 6 Meg Ohms to ground , the other two 20+ meg ohms . The motor pump coupling turns freely . Did smell a slight burning smell when pulling the motor terminals apart . 6 lead 480v motor . We are sending the motor out just wondering why we aren't seeing a short ...