Check for single phasing !!
Check voltages at your supply point first,
could even be a blown fuse.
Also perhaps a high resistance contact on one of the phases of the contactor.

Take the load of the motor and see if it will start with no load.

Do an isulation test and continuity test on the windings and see if equal values are obtained.

If it is star delta, check all six wires if connected correctly or poor contacts somewhere.

edited for typo's RF.

[This message has been edited by RODALCO (edited 11-02-2006).]

The product of rotation, excitation and flux produces electricty.