Electromagnetic Overload Device

The motor is provided with protection that will disconnect it from the system before the motor is permanently damaged. All motors above 500 KW are to be provided with protection devices or equipment to prevent any damage due to single phasing. The rule stated above does not apply to the motors of the steering gear system installed on the ship.


Only on the detection of the single phasing, an alarm will be sounded; however, the motor will not stop as the continued operation of the steering motor is essential for the safety or propulsion of the ship, especially when the vessel is in congested waters or under manoeuvring.


Electromagnetic Overload Device:



In this device, all three phases of the motor are fitted with an overload relay. If there is an increase in the value of the current, then this relay activates automatically, and the motor trips.


This device works on the principle of the electromagnetic effect produced due to the current. 


As the current value increases, the electromagnet in the coil also increases which pulls the relay and activates the trip relay, and the motor is stopped. The time delay is provided in this system because while starting the motor draws a lot of currents which can trip the motor.  

Log in

Log in with Google

Log in with LinkedIn


Don’t have an account? Register Now