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Isolation transformer - getting full, rated kva

I am having my electrician install a Topaz 5kva isolation transformer (TP-91905-68) that will power 4 dedicated circuits in a seperate, dedicated sub panel. The electrician has 220v coming in off the main panel into the Topaz and then 120v going out of the Topaz to the sub panel. I thought I had read in one of the posts here that in this type of installation, if not done correctly, you cold actually only be getting 1/2 of the rated output of the isolation transformer (so, 2.5kva versus 5kva).

If anyone has knowledge of this particilar isolation transformer in this type of configuration and can shed some light on the situation (if in fac there is an issue) I would be very grateful.
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saygrr
72 posts
 
Do you have the owners material? I have the Topaz 7,200 watt step down transformer. I will check the owner material for it. I also have it grounded separately with a separate sub panel. It definently reduces the noise. Blacker back ground. Better imaging.Your doing your system and your self a favour.
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dangelod OP
40 posts
 
No, no owners manual and was not able to find one online.
ngjockey
1,042 posts
 
It's 220/440-120/240. That means that it will have 4 output conductors (not including ground) and they would be wired in parallel for 120V and series for 240V. It's possible to use only half but it's hard to imagine an electrician doing that.

Don't remember if Topaz uses the H1-H4/X1-X4 convention. If it's new, there should be some sort of schematic inside the "end" enclosures.
saygrr
72 posts
 
I asked the electrician here at work. The wattage does not change when voltage is halved or doubled. the amps would halve or double. I think it would be a good idea to get an owners manual and make sure it is wired correctly. My owner manual does not include your model. If it did I would have made a copy and mailed it to you. Ngjockey is right there might be a schematic in side the cover. What you are doing is a very good idea but make sure it is wired correctly.

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