1966 10EE Electrical Connection with 230V Three Phase with a High Leg

Just got another 10EE (1966) in the show room and was wondering where the high leg should be connected? I have 230V with one high leg of 230v to ground. It does have a coolant pump.

Monarch has been inconsistent with respect to high-leg (which is akin to maufactured leg in an RPC system).

If you trace the wiring around the main contactor you will find that one end of the circuit which includes the main contactor's coil goes to one input terminal. We'll call that A for now. And if you continue that trace you will find that the circuit goes through the coil and also the overloads. We'll call that C for now.

You want the non-high legs to go to A and C. Obviously the high-leg goes to B.

This is really more of an issue in an RPC system where the B leg is subject to periodic droops as loads are applied.

The presence of a coolant pump is significant on later machines as these, too, utilize contactors and overloads with the same issues.

It was the M-G machines which had a main contactor for protection of the M-G itself, but employed no protection for the coolant pump (it was controlled through a simple drum switch).

Thanks Peter. Runs great, and it came with two new tubes in boxes and extra smaller tubes!!