Long time reader, first time poster: A question came up here at work regarding a small project where we want to provide 120 VAC on a machine fed with 380 VAC wye. One can purchase a multi-tap transformer with the options to use 2 legs of the 3 phase service, or one 220 VAC leg and neutral, on the high side and jumpering, and interconnecting as directed. My question is this: In this case, is one method inherently better than the other? I'm thinking from efficiency, heat generation, noise, or other power loss factors I don't know enough to consider. Both methods give you what you want in the end, which is single phase 120 VAC power with a Line and a Neutral, but there must be trade-offs in the design of such a transformer, no?
Multi-tap Transformer Question
- Thread starter DeanFran
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Is this something you are sending overseas? We don't have 380V services here.
But assuming so, if you have a transformer that can be configured for both, I would opt for the 380V L-L primary connection. Less current, less heat.
A machine we purchased used from overseas, and we use a 480 Delta X 380 Wye transformer to provide electrical service. I do have a 3KVA encapsulated transformer that can be configured for both that I am intending to use. We've wanted to provide 120 VAC service on this piece of equipment for some time. We need to replace a small conveyor, and it offered the perfect excuse to do it. In addition to powering the conveyor, having 120 VAC on board will allow me to install a single duplex outlet so operators and maintenance folks can plug in a laptop, or calibration equipment without having to run an extension cord from a nearby wall. Less current and less heat sounds good enough for me. Thanks.
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