Buck Boosters

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perlin68

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I have Customer that purchased two 0.25 buck boosters from a national ele. supplier who told him that thay would boost the current from 208V to 240V. The equipment draws 80 amps. I don't Know if I was reading the instructions wrong, but it said that the 0.25 booster would only be good for a 16 amp circuit. Can anyone help me with this problem?
 
The supplier only sent two, but we need three. Sorry, no cat#. It was from a cutler hammer dealer.
The line and load conductors are #2. The conductors to the booster are #12.We also didn't see where we would have the room in the bottom of the unit to make the connections.
 
Most boosters have a seperate line and load connection, right? Not a tap, like a surge supressor. Or am I way off here?
 
perlin68 said:
Most boosters have a seperate line and load connection, right? Not a tap, like a surge supressor. Or am I way off here?
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Not really. They're autotransformer connected. No real line and load, per se.

edit... Primary and secondary, I should have properly said.
 
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Because you connect them as an autotransformer the K.V.A. is greatly increased. If you are connecting a three phase load you may only need two and connect with an open delta connection. For 240 3 wire I believe you need three. IMO.
 
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perlin68 said:
The supplier only sent two, but we need three.
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Are you sure?

If you boosting straight 3 wire 3 phase all you need is two.

If your boosting three phase with a neutral then you will need three.
 
chris kennedy said:
So is this right? Or would it be 2560?208=12.3A?
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Both are right if you are trying to feed 2.56 KVA.

12.3 amps "input" and 10.7 Amps output.

All 10.7 amps flows through the 32 volt boost winding (10.7A x 32V = 341 VA) and 12.3A minus the 10.7 A= 1.64 amps flows in th 208 V winding. (208V x 1.64 A = 341 VA).

But, the OP says the load needs 80A at 240V = 19,200 VA. 19200 VA @ 208V = 92.3 A.

80A x 32V = 2560 VA = the desired rating of the boost transformer.

The 208 V winding carrys (92.3A -80A) = 12.3 A. VA= 12.3 x 208= 2558 VA

The 2.5 kVA boost transformer can boost 19.2 KVA from 208V to 240. This is per transformer or per phase.

I would check the nameplate. Maybe you got a 0.25 kva isntead of a 2.50 kVA.
 
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