State the possible causes of a synchronous motor failing to start.

1. Lack of power supply: If the motor is not receiving sufficient power supply, it may fail to start.

2. Faulty starting capacitor: If the starting capacitor of the motor is faulty or damaged, it may prevent the motor from starting.

3. Mechanical issues: There may be mechanical issues such as bearing failure, rotor or stator winding damage, or misalignment that can prevent the motor from starting.

4. Overload conditions: If the motor is subjected to overload conditions, it may fail to start due to excessive stress on the motor components.

5. Incorrect wiring: Incorrect wiring or connections can also prevent the motor from starting properly.

6. Faulty control system: If the control system of the motor is faulty or malfunctioning, it may prevent the motor from starting.

7. Environmental factors: Extreme temperatures, humidity, or other environmental factors can also affect the starting of a synchronous motor.

1. Insufficient torque. The synchronous motor may not be able to develop enough torque to overcome the starting load. This can be due to a number of factors, such as:
- The motor is too small for the load.
- The motor is not properly aligned with the load.
- The motor is not receiving enough voltage.
- The motor is not receiving enough current.
2. Electrical faults. There may be a fault in the motor's electrical system, such as:
- A short circuit in the windings.
- An open circuit in the windings.
- A ground fault.
3. Mechanical faults. There may be a mechanical fault in the motor, such as:
- A bearing failure.
- A shaft misalignment.
- A broken rotor bar.
4. External factors. There may be an external factor that is preventing the motor from starting, such as:
- The load is too heavy.
- The power supply is not stable.
- The temperature is too high or too low.