transformer question

I have a Square D 3S1F 3kva 480vac to 120vac transfomer that I want to use on a machine to run 1 single recepticle. My question is should I tie the common to ground? The reason I ask is I have the transformer grounded properly as well as the recepticle but I show an open ground with my circuit checker.

Jamey

Yes, the X0 terminal should be bonded to ground.

Thanks I will try that tomorrow

Sprek,

According to my Square D catalog, 3S1F is a single-phase 3 kva transformer with 240/480 volt primary and 120/240 volt secondary. It has secondary output coil terminals X1,X2 and X3,X4. There is no defined "common".

Whichever secondary terminal you decide to make your neutral point should be connected to your ground electrode.

There are two wiring choices: (A)connect X2 and X3 together, giving 120 volt legs between X1 and X2-X3, and X4 and X2-X3, with 1.5 kva available on each 120 volt leg, or (B) parallel X1-X3 and X2-X4, with 3 kva available on the one 120 volt leg.

I have it wired for B 120v 3kva

is you run your input on 480 2 out of 3 phases?it 's fine and mandatory to ground the output to any of the 2 common joint

if you run the primary with an already grounded line like a phase to neutral source (in your project this is not likely to happend but for exemple... a 277v), you would need to check which side of the transformer get the magnetic coupling with this primary ground. Because grounding the secondary will make a direct connection from 1 primary and 1 secondary terminal.

I got it thanks everyone

is you run your input on 480 2 out of 3 phases?it 's fine and mandatory to ground the output to any of the 2 common joint

Click to expand...

I always have grounded my common leg but I usually only have 500va or smaller transformers and they are always the open type. I just wanted to make sure on the sealed ones it was the same