CaseyR
New member
- Location
- Wasco County Oregon
After several years of trying to get my plans through the various regulatory agencies, I am hoping to finally start building my house and shop. Since like many (if not most...) I am seriously underfunded when it comes to building my dream shop, I will need to do most of the planning and construction myself.
I have recently gone completely deaf, so trying to discuss technical subjects verbally is challenging, to say the least, and a lot of information said to me tends to fall through the cracks of my current communications capability. Lip reading is not my forte and most people don't like to get writer's cramp by scrawling out a treatise for me... Thus I turn to your expertise for assistance. Unfortunately, since I have never worked with 3 phase outside of an EE lab and my last college course covering 3-phase power was about 50 years ago, my knowledge in this area has pretty much faded. (Oregon State University circa 1961, back in the days when 3-phase power was the basis of the electrical engineering program...)
My location is in northern Oregon not far from the Columbia River. Electrical service is provided by a local "People's Utility District". The PoCo engineer said they can supply either 240 volt or 480 volt open Delta or Wye 3-phase power at the same cost. When I gain some more insights here, I will talk to them again and see if I can absorb a bit more. The engineer at the PoCo can help with some details, but I have to make the major decision of 240 vs 480.
For the shop, I just got a good deal on an industrial air compressor and a variable speed overhead bridge crane for the shop that requires 460 volt 3-phase service (far more than I need, but the price was right). I also have a welder that can utilize either 230 volts or 460 volts 3-phase. Since I will also need 120 volt and 240 volt single phase service, I am trying figure out whether it would be more practical (read "cheaper") to have the local utility supply 480 volt 3 phase or 240 volt 3 phase.
For the 460 volt circuits, the crane will need slightly over 10 amps, the compressor will use a little over 11 amps, and the welder will take 19 amps. From the shop to the house, I would like to split off a standard residential single phase service where I will have a heat pump for the primary heat source with electrical resistance heat as backup. For the heat pump, I may be better off running 3-phase something to the house, but otherwise should not need 3-phase in the residence. While I will need 230 volt single phase, I am not sure that I will really need 230 volt 3-phase, although 230 volt 3-phase equipment can often be purchased used for a lot less than standard single phase stuff so it would be nice to have. I may also be running some somewhat sensitive electronic equipment (computer controlled plasma cutting) so wild voltage instability would not be particularly welcome.
One minor advantage of 480v. service, of course, is that the conductors for the 150 foot run from the pole to the house (has to be underground) can be smaller than for 240 volt.
Used 3-phase dry transformers appear to be available on eBay for around $600 to $1000 but I have not figured out which might be suitable for my situation.
There are a number of posts on-line regarding various voltages and configurations, but the more I read on this the less certain I become. My current guess would be to do 480 volt 3-phase but I am not quite clear on the full range of advantages and limitations on the Delta and Wye configurations and on just what additional transformers I would need to get all the voltage/phase combinations I want.
Thanks
I have recently gone completely deaf, so trying to discuss technical subjects verbally is challenging, to say the least, and a lot of information said to me tends to fall through the cracks of my current communications capability. Lip reading is not my forte and most people don't like to get writer's cramp by scrawling out a treatise for me... Thus I turn to your expertise for assistance. Unfortunately, since I have never worked with 3 phase outside of an EE lab and my last college course covering 3-phase power was about 50 years ago, my knowledge in this area has pretty much faded. (Oregon State University circa 1961, back in the days when 3-phase power was the basis of the electrical engineering program...)
My location is in northern Oregon not far from the Columbia River. Electrical service is provided by a local "People's Utility District". The PoCo engineer said they can supply either 240 volt or 480 volt open Delta or Wye 3-phase power at the same cost. When I gain some more insights here, I will talk to them again and see if I can absorb a bit more. The engineer at the PoCo can help with some details, but I have to make the major decision of 240 vs 480.
For the shop, I just got a good deal on an industrial air compressor and a variable speed overhead bridge crane for the shop that requires 460 volt 3-phase service (far more than I need, but the price was right). I also have a welder that can utilize either 230 volts or 460 volts 3-phase. Since I will also need 120 volt and 240 volt single phase service, I am trying figure out whether it would be more practical (read "cheaper") to have the local utility supply 480 volt 3 phase or 240 volt 3 phase.
For the 460 volt circuits, the crane will need slightly over 10 amps, the compressor will use a little over 11 amps, and the welder will take 19 amps. From the shop to the house, I would like to split off a standard residential single phase service where I will have a heat pump for the primary heat source with electrical resistance heat as backup. For the heat pump, I may be better off running 3-phase something to the house, but otherwise should not need 3-phase in the residence. While I will need 230 volt single phase, I am not sure that I will really need 230 volt 3-phase, although 230 volt 3-phase equipment can often be purchased used for a lot less than standard single phase stuff so it would be nice to have. I may also be running some somewhat sensitive electronic equipment (computer controlled plasma cutting) so wild voltage instability would not be particularly welcome.
One minor advantage of 480v. service, of course, is that the conductors for the 150 foot run from the pole to the house (has to be underground) can be smaller than for 240 volt.
Used 3-phase dry transformers appear to be available on eBay for around $600 to $1000 but I have not figured out which might be suitable for my situation.
There are a number of posts on-line regarding various voltages and configurations, but the more I read on this the less certain I become. My current guess would be to do 480 volt 3-phase but I am not quite clear on the full range of advantages and limitations on the Delta and Wye configurations and on just what additional transformers I would need to get all the voltage/phase combinations I want.
Thanks
