Switchgear Control Circuit

It is better to have one more NO contact of spring return push button so when you want to check the healthiness of lock out then press it and check it.

The standard practice is to provide a pushbutton with NO contact to check the "trip circuit healthy"

This method will not put the relay coil or trip coil in partially energised mode.

The operator has to check the healthyness of the circuit by pressing the pushbutton.

We need to check the voltage drop across the lamp and the minimum operating voltage of the Lock-out relay. Almost all the relays are designed to operate at 85% of the control voltage. If the voltage across the lock-out relay falls in this range, it may result in malfunction. Pls check with your vendor before approval.

Regards,

Manimaran.V

That is a normal way of monitoring the condition of your Lock-out Relay and your Trip coil. The advantage of that set up is that there is an online monitoring of the condition of the coils which you will not have if you are going to use a separate test circuit. You can approve it and still get a good night sleep.

JBA

Thanks all who participated. It helps lot.

- MS