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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

Showing 6 responses by ngjockey

ngjockey
1,042 posts
 
LOL

Haven't worked on a Topaz 120/240, but that looks right. Check it with a meter. You can get GFCI cords.
ngjockey
1,042 posts
 
Check the print on the back of the units or the manuals for the equipment's maximum amp draw.

V (voltage) times A (amps) = VA = watts

Rule of thumb for audio is that xformer should be at least double the combined draw. 80% is the "industrial" rule.

As far as the rest, wow, leave it to the electrician. You started off good.
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.
ngjockey
1,042 posts
 
Math is correct. 80% would be 720W.

Apple TV - reports from 20 to 48W
DIP - negligible 6W

Vide switcher/Tivo ???
My HD tuner/PVR is rated for 4A max (480W) and it can get warm.

Pre/DAC ???
examples: Plinius M8 - 20W, ARC LS17 - 50W, SFL2 -135W

Putting everything on a single isolation xformer defeats some of the purpose, don't you think? Particularly if you're mixing digital with analog or SMPS with linear power supplies.

How is the xformer for noise and heat? Shouldn't be uncomfortable keep your hand on.
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
 
Don't see any advantage of the xformer for the video switcher, which is essentially just relays. Wouldn't even try the amp on it, as much for the way it draws (half cycle cap recharging), combined with the capacity. TV is a noise source and one of the things to isolate from. Aside from that, glad it works and happy for you.

Now, you just have to try every brand of power conditioner to it and tell us how they compare.

Would've liked to see the electrician's expression when you mentioned balanced AC.
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