240v -480v 3 phase transformer

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Rico suave

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electrician
What are the issues of using a 240v primary step up transformer to 480v using a 120/208 service.. client want me to hook it up. The lowest I can change taps is 214v inside the unit..
 
Other than low voltage, no problem.

Sounds a bit uncommon to have a 214V tap on a 240V primary, I'd suggest posting the transformer nameplate.

Jon
 
Rico suave said:
What are the issues of using a 240v primary step up transformer to 480v using a 120/208 service.. client want me to hook it up. The lowest I can change taps is 214v inside the unit..
Click to expand...
If your input is about 208V, you only get 416V in the output! Please check if your service voltage can be raised a bit to 220V (I doubt that can be done but just maybe) to arrive at a 440V output. I have seen lots of 480-volt motors do well when supplied with 440V.
On second thought, since you mentioned you can change tap to about 214/480V, you're okay with a 467V at your output terminals!
 
5% taps are common, 10% are less common but certainly exist, but that would give you 216, not sure where you are getting 214 from. Is that is stated on the transformer or is it measured? I usually find 208 voltage to run on the high side, so if that is the case there, you are likely spot in with the "214"
 
Wow.. this really works.. thank to everybody that replied..

so i did connect the unit. My service is 120/208 3 phase.. I get 208 phase to phase on all 3.. I was getting 450v on the secondary side.. Changed the taps to the 214v input option.. Only had 5 this was the lowest tap to match voltage input... After this change voltage increased to 465 -470 v on the secondary side..
The unit plate reads 240-480.. I called the manufacturer and explain the situation and said it was the wrong transformer and that i should get a 208-480 transformer..
I explain it to customer and hes ok.. Machines are working fine.. I just want to make sure or understand if 208v to transformer will damage it somehow..
 
Ordinary transformers have no problem operating with reduced input voltage. They simply provide correspondingly lower output voltage.

The current rating doesn't change, so using a transformer at lower voltage means lower kVA capacity.

Jon
 
Rico suave said:
Wow.. this really works.. thank to everybody that replied..

so i did connect the unit. My service is 120/208 3 phase.. I get 208 phase to phase on all 3.. I was getting 450v on the secondary side.. Changed the taps to the 214v input option.. Only had 5 this was the lowest tap to match voltage input... After this change voltage increased to 465 -470 v on the secondary side..
The unit plate reads 240-480.. I called the manufacturer and explain the situation and said it was the wrong transformer and that i should get a 208-480 transformer..
I explain it to customer and hes ok.. Machines are working fine.. I just want to make sure or understand if 208v to transformer will damage it somehow..
Click to expand...
Thanks for getting back at us and providing the closeout!
 
Rico suave said:
Wow.. this really works.. thank to everybody that replied..

so i did connect the unit. My service is 120/208 3 phase.. I get 208 phase to phase on all 3.. I was getting 450v on the secondary side.. Changed the taps to the 214v input option.. Only had 5 this was the lowest tap to match voltage input... After this change voltage increased to 465 -470 v on the secondary side..
The unit plate reads 240-480.. I called the manufacturer and explain the situation and said it was the wrong transformer and that i should get a 208-480 transformer..
I explain it to customer and hes ok.. Machines are working fine.. I just want to make sure or understand if 208v to transformer will damage it somehow..
Click to expand...
What does voltage look like when loaded?
 
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