A Y225M-6-30KW, 380V, 59A motors, and some time after the normal start-up, but with half an hour after the load operation, the motor will be overheated, do not smoke, no Charred smell, and a basic balance between supply voltage, and stator winding current imbalance is obvious, namely 80A, 47A and 46A.

    This is a used motor, in the past has been running normal, indicating that error-free wiring. Three-phase voltage and the basic balance, then the three-phase current imbalance caused by the reasons for the existence of only the stator winding short-circuit or open circuit down. According to motor overheating and not only smoke, no Charred smell can not short-circuit proof.

    See from the three-phase current imbalance, 46A and 47A are very similar, and 80 = 1.73 * 46, isconnected with the triangular phase motor circuit, which constitute the same as V-shaped connection.

    The motor for the star - triangle switch start-up, normal start-up that when start-up (that is, then into a star) Motor circuit, if one phase circuit, the motor can not start on three-phase motor winding open circuit fault does not exist. After start-up into a triangle connected to one phase of circuit operation, the issue should appear in the star - triangle switch operation file, that is part of the triangle connecting. Inspection star - triangle switch operation of the contact file and found that a contact can not contact the Department of insufficient pressure, after adjusting for fastening, the fault that is ruled out.