I’ve done this before by changing transformer taps on a 120/208 volt transformer to step up to 220 volts but I also advised against doing it, but owner wanted a quick solution.Are you referring to a 1 to 1 ratio transformer? You might be able to boost the voltage a bit with the primary taps but I don't think that this is a good solution. Let's see what some of the engineers say.
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My bad i was assuming wire was not ran yet, but if feeder is already ran then a boost transformer at feeder termination may help?
Upsizing is an option but wanted to keep the costs down. Running AL 1500ft or more in some places. I was thinking of SER cable in the joist space. That puts me at at least 250kcml for 480/3. I was trying to keep it at 2-2-2-2
Yes, 1:1.Are you referring to a 1 to 1 ratio transformer? You might be able to boost the voltage a bit with the primary taps but I don't think that this is a good solution. Let's see what some of the engineers say.
Welcome to the Forum.
Yes i realized later that upsizing wire world be too costly for the size of your warehouse. So why not consider using existing wires with a buck/boost transformer at termination of your feeder(s) and before sub panels?
This is a very bare bones core and shell right now. The largest load I have available to use is 480/3 at 30A (unit heaters). The skid(s) Im trying to feed are a 480/3 100A disconnect>75kva>208/1. All fed from 480/3 90A breakers Im installing at a house panelboard. Trying to keep the 480v to the skids and step down after the disco. I was thinking that a 1:1 at 700ft (roughly) may help me get the other roughly 700ft to the skid.
Whats the calculated load at the end of the 1500 foot run all 75 kva plus 30A @ 480 three phase? (not breaker sizes but actual load)
This is a temp power install using portable skids. There is no calculated load for it. Most likely will never exceed 100A @ 208/1.
Not sure. This is all temp power. No lighting. Just equipment and tool charging. Maybe some cord connected drills and other hand tools. Question is based on anticipation. Distances are long, but loads are minimal, cant imagine them ever exceeding 100A. Probably wont come close to that either.
by 208/1 do you mean you'll have a 2 wire+ground 480 feeder to a single phase 120/208 transformer?
1:1 gains you nothing. All your losses are in resistance of the conductors. In fact if a marginally sized transformer for the load supplied you actually might see more VD than if you didn't have the transformer.
As stated, if you want a Voltage boost you would use an autotransformer connection (buck boost). The autotransformer carries only a small faction of the total load so is much smaller. !2V or 16V boost x load Amps = autotransformer kVA size.
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