Single Phase source Three phase Out Drive

[Billgas]

I have single 120/240V 400A service.

What is the largest three phase motor that drive equipment can power?

 

[davidbeach]

0 hp. You at least need a three phase service or some sort of phase conversion equipment to get to 3 phase.

 

[cranky108]

Depends on if you are looking at a mechinical or electronic converter, or there maybe a hybred type out there.

Why don't you Google it and let us know.

 

[ScottyUK]

Assuming you do intend to use a converter of some kind, inverter-type VFDs designed for the purpose tend to be available up to no more than about 4kW. After that you can usually push a three-phase input drive into service with a bit of effort (add DC bus capacitance) and de-rating (halve it). That gets kinda expensive quite quickly.

Motor-generator sets are available in enormous ratings, but I think you'll struggle to find a really large single phase motor to drive one: about 25HP is the highest I've seen, and that was a real old one from some piece of farm machinery.

Phase converters are available up to reasonably large ratings but the third phase they produce is not very good - weak and it doesn't have a true 120° phase displacement - plus they normally need to be tuned to the load they serve.

Have you asked the utility to cost installing a 3-phase supply?


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If we learn from our mistakes I'm getting a great education!

 

[BJC]

Look at VFD. Single phase in and 3 phase out are common. I don't know how big they come but they work fine on gate operators where there is just a single phase line running by. You can probably save the cost of the drive on the motor. Single phase motors in 4 or 5 HP are not cheap and they are hard to find.

 

[jraef]

Any 3 phase VFD is theoretically capable of acting as a "phase converter", but not all will do it because some have phase loss protection on the front-end that cannot be defeated. So assuming you get around that issue, the maximum size is at that point only limited by your supply capacity. You say you have a 400A service, but how much is already running on it?

BTW are you the same Bill I already answered this question for in another forum, but where you had a 200A service? If not, read this.

http://forums.mikeholt.com/showthread.php?t=123505

If so, your 400A service obviously increases the limit. But as I said in that other thread, there are other issues at hand.


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