A synchronous motor can fail to start for a variety of reasons. Given below are few of them:
- Incorrect Voltage: Synchronous motors require a specific voltage to start and operate properly. If the voltage supplied is too low, it can prevent the motor from starting. On the other hand too high voltage is also dangerous for the motor.
- Faulty or incorrect connections: Incorrect connections in auxiliary apparatus can be one of the reasons.
- Incorrect Power Supply Frequency: Synchronous motors are designed to run at a specific frequency. If the power supply frequency deviates significantly from the motor’s rated frequency, it may fail to start.
- Rotor Lock: If the rotor is mechanically blocked or jammed, the motor may not be able to start. This could be due to issues with the bearings, mechanical obstructions, or misalignment.
- Faulty Starting Mechanism: Synchronous motors often have a separate starting mechanism, such as a squirrel cage induction motor or a DC motor. If this starting mechanism fails, the synchronous motor won’t start.
- Loss of Excitation: Synchronous motors require a magnetic field to be established in the rotor. If the excitation system fails to provide the necessary field current, the motor won’t start.
- Faulty Stator Windings: Issues with the stator windings, such as short circuits or open circuits, can prevent the motor from starting.
- Incorrect Phase Sequence: If the phases of the power supply are not in the correct sequence, the motor may not start. This can be due to incorrect wiring or a fault in the power distribution system.
- Overloading: Attempting to start a synchronous motor under heavy load conditions can lead to failure. Ensure that the motor is not overloaded during the starting process.
- Mechanical Issues: Mechanical problems such as excessive friction, misalignment, or bearing issues can prevent the motor from starting.
- Control System Failure: Issues with the motor control system, such as a malfunctioning starter or control panel, can prevent the motor from starting.
So that was all about the possible reasons of a synchronous motors failure to start.
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