Powering of Space Heater in a Transformer LCP (Local Control Panel)

Am I missing something here or is your undervoltage relay sensing that supply 2 is unpowered and so tripping out on undervoltage alarm? This explanation makes the most sense.

A simple way to fix this could be to parallel connect the two supplies (1 and 2) together, BUT YOU must check the manuals and datasheets and manufacturer's literature to ensure this is possible (and safe) BEFORE you attempt this. There must be a reason why there is a second supply to the panel (redundant power feed perhaps).

Check the manuals and datasheets as there should be adequate explanation as to the operation of the interlock, undervoltage release and dual supplies. Let us know what you find.

Thanks for your answer.

The two supplies have their own seperate undervoltage relays and seperate breakers to take in power to the interlock circuit,so i felt powering one supply will not be a big deal.am wondering if my connection is wrong.I connected a three phase(no nuetral) directly into the circuit as shown in the diagram but the secondary side blends with the 3 phase and has the fourth terminal strongly earthed.My line to line is ok and my line to nuetral is also good.

NB

what is a CAM selector switch?i suspect this is the problem

u ve to use 2 uvr for the 2 supplies such tht when one uvr is energised the other shouldnt get energised........this s done in the control circuit of the uvr and the contactor...........

Dear friend,

Kindly check your installation, operation and maintenance manual of your equipment. analyze also the schematic and wiring diagram of your local control panel how these two power provisions are being opted to supply your transformer's heater when needed. I am sure there is a protection/interlocking contacts or safety device integrated in your control circuit preventing the closing of your magnetic contactor to switch on the power supply for transformer's heater.

I do hope this simple idea of mind will help you.