Introduction to 3 Phase Appliance Protector Electrical Engineering Project:

In many industries we find 3 phase motors for running different equipment. The three phase are less expensive and they can be started easily when compared to that of DC motors. The three phase motors are very sensitive and they get damaged when any of the phases does not work and they draw huge currents to the load from the available two phase which causes breakdown. To avoid this we will use single phase preventer to avoid the damages caused due to phase faults. In this paper we will see how the single phasing preventer works and how is it connected to the three phase appliances.

Brief on working of single phasing preventer:

In three phase motors if any of the phase fails the other two phases make the fields to produce the required torque for the load which damages the appliance. The single phasing preventer uses a IC NE555 for driving the relays. In this two phases are connected to the relays and there are connect in such a way that they act as a enabling device for the other when one relay is energized.

The relays are connected serially so as to obtain a AND gate logic which makes the device on when both the inputs are high. The availability of the one phase makes the other two phases to get on by the IC, if any of the phases fails then the other phases does not get on. So this prevents the other two phases to get available to the appliance and the device gets off automatically.

Advantages of using single phasing preventers:

This is a efficient device which automatically makes the appliance off when any of the phase does not work which prevents the device from getting damaged. This device is a low cost and it has only a delay of 4 seconds to make the appliance off when a phase failure is detected. 

Download  3 Phase Appliance Protector Electrical Engineering Final Year Project Report.