Single phase or 3 phase savings


Old 04-09-09, 04:28 PM
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Single phase or 3 phase savings

How much can I expect to save, percentage wise, between single phase and 3 phase?
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Old 04-09-09, 04:57 PM
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Or we talking motors, pure resistance heat. Commercial or residential? New or retrofit? I can't answer your question but I'm pretty sure these are things the pros will need to answer your question.
Old 04-09-09, 05:08 PM
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You will not save anything on your electric bill one way or the other. Watts is watts, VA is VA no matter if it 3 phase or single phase. The savings of 3 phase over single phase is in building the system (materials), since you can get more capacity for not much more materials, plus you can use smaller circuit breakers, and wire sizes.
Old 04-11-09, 12:08 AM
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This is pretty broad question about saving the cost on 3 over 1 system.

95% of North American homes are on single phase supply few do have three phase supply however some are on old delta system and this is a tricky system to deal with it and new home if they used three phase system useally are WYE system which it is safer to use.

However.,, A major gotcha is the POCO system that something you have to dig it up to see what their requirement and most POCO I know in Wisconsin area will not useally give three phase supply to resdentail area unless large apartment complex or near commeral location then you can get either single or three phase at 120/208 volts

And also the cost to hook up three phase service useally more than single phase system { unless you got super large house or super heavy load then it may justify the cost of the three phase system.}

As far for the rates I know it is not much diffrence there however some do have peak demand rates that part it get ya by suprise if not carefull with it.

Old 04-12-09, 07:50 AM
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3-phase obtains savings with electric motors only.

So if you have a lot of big electric motors - a high rise with elevators and central A/C, water pumps, etc.

Or an industrial manufacturing plant with a lot of electric motors.

Or a resturant with all sorts of electric motors.

Then it might be a good idea to use 3 phase instead of single phase.

HOWEVER, in these days of energy savings needs... you can use single phase with a "wiz bang" computer controller/inverter and smart design of the entire system to obtain all sorts of additional energy savings!

These not only convert single phase to 3 phase via an inverter, but also use a smaller more efficient 3 phase electric motor and control to alter the electricity supplied to the electric motor via computer control.

All you need to do is purchase new single phase "Energy Star" appliances and A/C. Then you will probably be further ahead than just 3 phase.

Read all about it here...
Cool Electronics Hot A/C | The road to energy efficient HVAC may lead to variablespeed compressor technology and new electronics to drive it | heating, ventilation, and air conditioning (HVAC) systems | Machine Design
Old 04-12-09, 11:18 AM
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I see very little, if any true savings in a residential situation.

In commercial and industrial situations there are savings in the costs of installations and electrical usage.

I have never seen a residential refrigerator, washer, dryer, or heater that is made for 3 phase. The amount of wire is a typical residence is minimal compared to most commercial or industrial installations so copper costs savings would be minimal.

3 phase equipment is typically more expensive than single phase so most any savings realized in usage or copper savings would be more than offset by the increased costs of equipment designed to utilize 3 phase power.
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