How to adapt a 550v 3 phase machine to run on 220v in Canada.

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GummyMonster

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Evening,
I've been reading and searching the net and this forum, but haven't found exactly what information I need. I apologize if I missed this answer, but I'm under a short time limit to make a decision. If not this particular equipment, then very possibly others having the same power requirements.
There is some older equipment for sale that I'm interested in, however it is mostly run on 550 volt 3 phase power. I'm hoping someone won't mind explaining what I would need to run this equipment on 220 volt.
I believe an vfd and/or transformer is needed, but what sizes and brands I should be pricing out. If there is a better way to do this, I'm completely open to other ideas. I want to do this properly, not diy a system together or use power conversion that barely works.
Thanks in advance for any help,
Ken
 
Last edited:
Wow. True two phase power is very unusual. Supposedly there is still some in Philadelphia. I am curious to see answers from the resident experts!
Yes:

Two-Phase Electrical Service - Continental Control Systems, LLC

What is two-phase electrical service? Residential electric service in the United States (120/240 Vac) is sometimes called two-phase service but this is NOT correct. It is only single-phase, since both line voltages are derived from a single phase of a distribution transformer with a center...
ctlsys.com ctlsys.com
 
Definitely find yourself a good electrician. He can help and save you time and money.
A rotary phase converter will convert your 240 volt house hold power to 240 volt three phase. You then need a 3 phase step up transformer to step the voltage up to 600 volts. This can be expensive unless you can find used. A lot of transformers are 208 volts three phase. You could give Hammond Power solutions a call and see what they have. Make sure you are sitting down when they give you a quote.
If you can find machines with 208 -240 volts you can save the step up transformer.

Martin. ( not even remotely close to knowing electrical. Just trying to help)
 
Is Canada the same as the US with 120/240v split phase?
 
GummyMonster said:
Evening,
I've been reading and searching the net and this forum, but haven't found exactly what information I need. I apologize if I missed this answer, but I'm under a short time limit to make a decision. If not this particular equipment, then very possibly others having the same power requirements.
There is some older equipment for sale that I'm interested in, however it is mostly run on 550 volt 2 phase power. I'm hoping someone won't mind explaining what I would need to run this equipment on 220 volt.
I believe an vfd and/or transformer is needed, but what sizes and brands I should be pricing out. If there is a better way to do this, I'm completely open to other ideas. I want to do this properly, not diy a system together or use power conversion that barely works.
Thanks in advance for any help,
Ken
Click to expand...

Please advise how you know the machine is 2 phase.

I suspect that the machine is really 3 phase 550v like my surface grinder is. Most commercial machinery in Ontario and Alberta is 3 phase 575v.

In our situation we needed to convert single phase 240v residential power to 3 phase 240v power and then use a 3 phase transformer to step the voltage up to 600v that our machine can run on. This equipment alone runs over $2000 CAD making that "cheap" machine much more expensive.

This is why those who go this route size their rotary phase converters and transformers to allow for the use of more than one machine to make it economically viable.

OPTION 2

replace the original equipment motor(s) with either single phase 240v motor if possible; or replace with 3 phase 240v motor and then add a variable frequency drive. But many machines have multiple motors, our surface grinder for instance has 5 motors, and many of them are hard to source.

For more specific help give us the machine type and details.
 
Martin W said:
Definitely find yourself a good electrician. He can help and save you time and money.
A rotary phase converter will convert your 240 volt house hold power to 240 volt three phase. You then need a 3 phase step up transformer to step the voltage up to 600 volts. This can be expensive unless you can find used. A lot of transformers are 208 volts three phase. You could give Hammond Power solutions a call and see what they have. Make sure you are sitting down when they give you a quote.
If you can find machines with 208 -240 volts you can save the step up transformer.

Martin. ( not even remotely close to knowing electrical. Just trying to help)
Click to expand...

sorry I missed your post when I made my own and ended up duplicating much of the information. I will add though that 208v transformers will not work, according to phase quest they must be 240v secondary and 600v primary if you have 550 to 600v machines.
 
Assuming you are really talking three phase, a 240-600 isolation boost transformer with 600 as the secondary is what you need. They are much more common in Canada and can be found used. You need to be careful about running a step down in reverse due to grounding issues. Dave
 
When you say the motor is "2 phase", is that truely what it is? Or single phase with a center tap. The two are distinctly different but read the same with an ohmmeter. I haven't worked with 2 phase since I was in the Pacific in ~'84-5. Some theorys that may be of assistance:

Motors: Single phase on high voltage winding the two phases are at 180 electrical degrees to each other. Such as the 2 sides of a 240 volt split into two 120 volt lines. With 3 phase motors, the three phases are at 120 electrical degrees from each other. Most 2 phase I have encountered was at 90 electrical degrees. That's not to say all of it is, just what I have encountered.

First: A 3 phase motor will run at reduced voltage with little or no problem except the reduced power. With 550 volts common in Canada, I would speculate that a 550 volt motor could be run at 480 volts with reduced horse power.

Next: A 3 phase transformer is nice, they reduce the overhead and auxillary equipment for a "new" install. For a hobbyist, 3 single phase transformers are the same thing just not in one enclosure. They needn't even be the same size, so long as the smallest has the capacity for the load. ie. For a 1 KVA load, a single 1 KVA transformer and two 1.5 KVA transformers work fine. Of course, they must be the same voltage ratings.

Third: It is quite possible to run 3 phase transformation with 2 transformers. It is (was in my day) called "open delta". The load is reduced to 56%, so there are limitations. You would have to be the judge on that, but it most certainly can be done. The maximum current is the limiting factor here. For a 1 KVA load, running two 2 KVA transformers will provide sufficient current.

All in all, if 3 phase is available, it would be possible to run a 2 phase 550 volt motor on 480 volt 3 phase. It would require an inductor (one side of a transformer would do) with a current rating the same or higher than the motor be connected between the 3rd phase and the common point on the motor. Just how stable the motor would be is questionable. Electrically it would be very imbalanced, to the point it may shake itself apart.

Such a test would be acceptable for a short period on a bench, but to use the motor in working service would be questionable at the least. And damaging to the motor and observer at worst. I will not recommend it, but electrically it is possible. If you have access to an old time motor man or motor shop, that would be your best bet. Even a Master Electrician will not be able to accurately answer the question. It will take a motor winder. . .

.
 
You haven't said what the machines are and whether the motors are proprietary or easily replaced. I've been down the 550-600v rat hole and even built a transformer, first with two single phase units wired open delta and then adding a third because the starting inrush was so high on the old motor. Testing 600v told me I was too clumsy to want to keep it on my lathe. 240v is scary but 600v is deadly with little room for error. My control wiring was also 600v and that is a deal breaker in my world.

If the motor is proprietary and rewinding and changing starter overloads is a big project, talk to a real electrical person about the proper transformer. Personally I would not run a 550v motor on 480 unless I was sure it would not get hot. Starving voltage without reducing hz can be hard on those old motors-even if they are tough. Easy to test but if you go the transformer route in Canada you might as well go with the correct one. You want the KVA to be 2-3 times what the largest motors need. Dave
 
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