Type of motor protection?
1. Overload protection
Protects motor from running at high currents for too long (due to mechanical overload, jam, etc.).
Example: Thermal overload relay.
2. Short-circuit protection
Protects motor winding from very high fault currents.
Example: Circuit breakers (MCB, MCCB, fuse).
3. Ground fault (earth fault) protection
Protects against leakage currents to earth, preventing electric shock and fire.
Example: Earth fault relay.
4. Phase failure (single phasing) protection
Protects against loss of one phase in 3-phase motors.
Example: Phase failure relay.
5. Phase sequence protection
Ensures correct rotation direction and protects against wrong phase sequence.
Example: Phase sequence relay.
6. Under-voltage protection
Trips the motor if voltage drops below safe limits, preventing overheating or staling.
Example: Under-voltage relay.
7. Over-voltage protection
Protects against high voltage which can damage insulation.
Example: Over-voltage relay.
8. Locked rotor protection
Protects when the rotor cannot turn while current is high (e.g., mechanical blockage).
