[dovrosenberg]

I am building a CNC plasma table and have a 1200 watt torodial power supply to power my stepper motors. I have been wiring up my other power supplies and testing for continuity as I go along. My input is 115vac (US). The neutral and hot wires are isolated thru out the system so far until I add the torodial power supply. It has 2 red wires that are supposed to be tied to neutral and 2 black wires that are supposed to be tied to hot. When I do that, the other hot and neutral wires now have continuity between them. They were isolated before. This doesnt seem right. It seems that there should be something between the torodial power supply and the other components of the system. Am I missing something?

[Al_The_Man]

There appears to be something bogus about the instructions, with ref to the 240v connections, but The connections seems to be OK for 120, i.e. two red together & two BLK together for 120vac .
When these pars are powered, you should have the correct secondary voltage, if the RED's & BLK's were wrong, the transformer would overheat?
I assume you want to power on 120V?

[RaderSidetrack]

When I do that, the other hot and neutral wires now have continuity between them. They were isolated before. This doesnt seem right. It seems that there should be something between the torodial power supply and the other components of the system. Am I missing something?

I presume you are referring to continuity checking with all power disconnected? If so, I don't see a problem -- the two coils that are the primary side of the transformer are just long coils of wire. If there was no continuity between hot and neutral it would be a defective transformer.

Its after power is applied that the transformer creates 'back EMF' which in effect is resistance that prevents what would otherwise be a short circuit.

As for the PDF, the instructions more or less say with 240VAC hook up the the primaries in series, or with 120VAC hook them up as in parallel.

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[Al_The_Man]

It is the parallel hook up that is critical, if wrong , IOW both windings have to be in phase.