Boosting voltage?

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vramp7

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My ques is can u boost 460 to 480 and get 100amps output?
Square d tells me to get a 600 pound trany that is 480 to 480 and that will do it. My supply house tells me to get 3 seprate 40 pound tranys one wire of 3 phase goes to each trany sepratly, that can go above the suspended ceiling. I dont understand how u can get the same output from two different trany setups. We are feeding a cat scan mach and too much voltage drop is not good.../
 
Square Ds solution is using a 1:1 transformer with 3 sets of coils and use one of the seven sets of taps to increase the voltage.

You supply house is suggesting three buck-boost transformers. In essence, the same 3 sets of coils, but each set in a seperate enclosure.

My concern would be once you increase the voltage to 480 when the machine is operating, what will the voltage be when it is 'idling'. Voltage drop is a function of amp draw.... the more amps the unit draws, the higher the voltage drop. So when the machine is not using much power, you may end up supplying it with 490, 500, even 510 volts. Can it stand that much voltage without damage?

A better solution would be to upsize the feeder.
 
I'm assuming that since you are starting with 460, this is probally not in the US. The buck/boost transformers the supply house suggests will work, I don't know why Square D is suggesting a 480 to 480 transformer, unless they figure on changing the percent taps on the transformer to boost the output. Voltage stability would probally be better though, since the machine is voltage sensitive.
 
You need to trend the voltage to determine the high lows and times of occurrence.

1. Is it 460 consistently?
2. Is 460 the norm in your area?
3. Why is this a problem?
4. Have you contacted the utility to see if they can change the taps on their transformer?
5. You can get auto tap changing transformers.
 
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The power co. had just changed voltage from 480 to 460 recently, Why I don't know. The hospital has already burned out chillers and probably other things. If u change to 480 why would u have 490 when idleing?
 
460, 470, 480, 490....What's the issue..

What is the lowest measured? what is the highest measured, select the taps that give you the best range within acceptable limits.

To have lost a chiller you would need more issues that 460 VAC.
 
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