A three phase motor running on two phases will continue to run in most applications. Therefore, phase loss can go unrecognized on most systems for a long enough time to ignite the motor. When the phase loss occurs, the motor will use all of its current from the two power cords.
Measuring the voltage at the motor will often not know the phase loss. The motor winding emits a voltage almost equal to the phase voltage lost. In this case, the open coil acts as a secondary coil of a transformer, and the two coils are drawn into a source acting as a primary coil.
The phase loss can be reduced by using a two-element fuse of the right size and by using the right size of the heating element. In electric circuits of the motor, or other circuits in which phase loss may not be allowed even for a short period of time, a phase-aware electronic device is used to know Get lost phase. When a phase loss is detected, the electronic monitor activates a set of contacts to release the starter coil.
Repairers can observe black burns on one of the coils 3ɸ, which occurs when a motor breaks down when the phase is lost. See Figure 8.6
Motor phenomenon due to phase loss
Phase loss caused serious fire and deformation to a phase coil (triangular joint)
Coils experiencing phase loss will indicate a clear and rapid defect, including the loss of insulation of a coil.
Phase loss is distinguished from the voltage imbalance based on the severity of the failure. Voltage imbalances cause less black burns (but more often on coils) and little or no deformation. Heavy phase ignition and severe deformation to single phase windings.