Thermal Overload Protection Single Phase Motors
They operate as a sensitive power cut out for both single and three phase motors.
Thermal overload protection single phase motors. Thermal overload relays t16 from abb electrification products. There is one cylindrical stator and a three phase winding is symmetrically distributed in the inner periphery of the stator. Thermal overload relays are one of the most common and economical motor overload protection devices especially for single phase motors. In single phase motors up to a given motor size around 1 1 kw it can be mounted directly in the main circuit to serve as an on winding protector.
Thermal overload or circuit breaker for single phase motor 05 02 2016 12 27 am many single phase motors have thermal protection cutouts built in in which case a circuit breaker of 15a can suffice. Due to such symmetrical distribution when three phase power supply. Thermal protectors can also be built into the windings see the illustration below. For understanding motor thermal overload protection in induction motor we can discuss the operating principle of three phase induction motor.
As mentioned thermal overload relays contain a bimetallic strip and a bimetallic strip is a mechanical device that converts temperature change into mechanical displacement. Offer reliable protection for motors in the event of overload or phase failure. Thermal overload relays are economic electromechanical protection devices for the main circuit. Such as thermal overloading or overheating can cause insulation failure and damage to the winding so for proper motor thermal overload protection the motor must be protected against the following conditions.
The overload relay is designed so the current to the motor is shared between phases so if you only wire up one phase then all the motor current goes through one of the contacts on the overload and you can actually create an overload condition. The t16 thermal overload relays are economic electromechanical protection devices for the main circuit. Single phase motor overload protection previously we discussed what a magnetic motor starter is a contactor and an overload relay. They offer reliable protection for motors in the event of overload or phase failure.