How to prevent supply to the welding transformer when not in use?

Turn off the breaker or disconnect switch that feeds the transformer.

Ben Miller

Do you mean that you want to prevent somebody else from restoring the supply to it without authorisation? If so, then is the equipment hard- wired to the supply, or connected via a plug and socket? If it's hard wired then install a lockable isolator switch, and lock it out when the equipment is not in use. If it's connected via a plug and socket, then things get a bit more difficult. You could install a lockable isolator for the socket, or a socket with a built-in lockable isolator, this would work best if there are only one, or a few, sockets of the type which the equipment uses, and no other equipment which needs to be used, via one of these sockets, when the wellder is not in use. Devices are available for certain types of industrial plug, which attach to the plug and lock in place, and which then prevent the plug from being inserted in a socket. Here is such a device which Mennekes make for use with ceeform plugs for example:

I susoect that similar devices are probably available for some other types of industrial plugs, but possibly not for domestic ones. If the equipment is connected via a plug and socket where in the World are you, and what type of plug does it use?

The objective is that only when the welder uses the machine the supply has to go to the welding transformer and energise.All other time the welding transformer should not receive the supply and hence losses can be minimised.

What size is the transformer (what is the kVA rating, voltage, etc?)