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Wiring an Isolation Transformer

I found a pristine, never been used, Topaz (Square D Company) 91018-31 1.8 KVA Ultra Isolator Line Noise Suppressor for $40. Other markings include .0005pF, 50/60 Hz, 120/240, Indoor Type 1, Enclosure Class 1-80 Insulation. However, it has no receptacle or chord.

My first question to the forum, is how to wire it? Could I just take a short extension cord, cut in half, wire the male end to the output side and the female end to the input side? Should I use bare wire under the screw terminals, or should I crimp/solder on spades? What wires go on what screw terminals? Some suggest balanced is the way to go. But some suggest this cuts the power in half, some suggest it doesn’t. Here is an example I found of balanced wiring:

Input:
Neutral (white) to H1
Hot (black) to H4
Ground to chassis

Output:
Hot 1 (white) to X1
Hot 2 (black) to X4
X2/X3 center tap connected to chassis ground and outlet ground.

Is this all there is to it? I am a complete newb when it comes to electrical work. Is this something I can do myself, or should I hire an electrician? Any assistance would be greatly appreciated.
cpalcott
jea48
2,944 posts
 
If the purpose of the exercise is to have a balanced secondary then he has no choice but to wire it as stated above. You can't have a 240 primary and balanced 120 secondary. Granted, you can argue that balanced might provide no benefit, but he won't know until he tries it.
Herman


Was it..... Was his mind made up?... Set in concrete?

Some suggest balanced is the way to go. But some suggest this cuts the power in half, some suggest it doesn’t. Here is an example I found of balanced wiring:
Cpalcott
Here is one company's comments on the subject.
http://bryston.com/pdfs/08/Volume10_Iss2.pdf
ngjockey
1,042 posts
 
http://minneapolis.craigslist.org/hnp/ele/2144150722.html ??

Yes, balanced output means derating by half. Whether the tranny will be agreeable (relatively cool and quiet) to 120V in/balanced out is always a mystery until it's tried. I've had one where that worked fine in one house but not when I moved. Switched to 240V in and it was happy again. If electricity and "newbies" is dangerous, xformers and "newbies" is a whole new level of fun.

Get a meter (with clamp or fork would be better) and test before hooking anything up. Klein Tools aren't expensive. Balanced is 60V leg to ground on both sides and 120V leg to leg.

I prefer GFCI outlets with balanced AC for added safety ( I like to open covers), but not required. In this situation, install an appropriate inline fuse/holder on the input side.

Wire nuts/"marrettes" are fine.
ngjockey
1,042 posts
 
Ok, maybe GFCI is required. Up here, it's CSA instead of NEC and, technically, there is no CSA provision for balanced AC.
herman
1,974 posts
 
Was it..... Was his mind made up?... Set in concrete?

Having a bad day? No need to be snippy. I said "if." I didn't say set in concrete,, I didn't say his mind was made up.

BTW I'm still curious how it is less isolated wired as 120-120.

.
jea48
2,944 posts
 
BTW I'm still curious how it is less isolated wired as 120-120.
Did you take the time and read the Bryston link I provided?
They recommend running the primary in balanced mode, 120/240V (120V 0 120V), instead of single ended 120V in.

As for recommending the OP try it first.... As a rule I try to stay within the boundaries of NEC code as well as UL safety guide lines.

NEC Article 647
Equitech
.

Curious, what are your thoughts on running the xfmr on 1/2 its designed rated voltage? (Series primary windings connected to 120V instead of 240V). What does it do to its efficiency?
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