changing single phase to three phase

[Jraef]

I have wondered why that is done for close 40 years now.:?

In my experience, it comes down to people buying cheap equipment without asking anyone about the electrical ramifications. People (by that I mean "non-electrical" people) typically have almost no clue about how electricity is distributed and even if they are told "this needs 3 phase", they don't know what that means, and/or they don't know what they have now! With the advent of Fleabay and other sites where people can buy used equipment dirt cheap from all over the world, this have become even worse. In the 80s, I worked for a German mfr here in the US and we had maybe 1 or 2 pieces of equipment per year that would be sent to us to be "converted" to work with US standards. Now, I get calls about that at least once per week, sometimes more. VFDs have made this easier to address, but it doesn't work for everything. The thing that almost ALWAYS happens is that when you explain to someone what this will entail, they suddenly realize that they didn't get a "bargain" at all!

 

[Besoeker]

I already did

Did it surprise you?

 

[Besoeker]

In my experience, it comes down to people buying cheap equipment without asking anyone about the electrical ramifications.

Probably not far off the mark.

 

[Ingenieur]

Did it surprise you?

not really after looking at the details

but useless
the thing is 5' long by 2' diameter and weighs 2700 lbs

clever, but not marketable

 

[Besoeker]

not really after looking at the details

I also looked at the details.
Input =480V and 163A FLC. So 78.24 kVA
Input power 74.6/0.955 So 78.11 kW
I'm sure you understand the significance of that.
Not very common for machines to have that sort of ratio.

I have come across large (above 1,000 kW) slip-ring synchronous machines that did so. But not a single-phase motor.
I'm not saying that it's impossible........

 

[kwired]

I can't see a utility in my area that would even allow it to be installed.

There is a single phase service supplying a 50 HP irrigation well about a mile from my house. Has static phase converter supplying three phase motor. Been there for 30+ years though. They wouldn't let that load on a single phase service today, but will let that existing one remain. Owner doesn't want to pay for upgrade to distribution to get three phase to the location, POCO does own and maintain the phase converter - but would like to eliminate it.

I have yet to see more then a 50 HP motor supplied by single phase source, and can't recall seeing a single phase motor over 16 HP.

 

[Ingenieur]

I also looked at the details.
Input =480V and 163A FLC. So 78.24 kVA
Input power 74.6/0.955 So 78.11 kW
I'm sure you understand the significance of that.
Not very common for machines to have that sort of ratio.

I have come across large (above 1,000 kW) slip-ring synchronous machines that did so. But not a single-phase motor.
I'm not saying that it's impossible........

look at its construction, large permanent magnet
basically runs as a synchronous machine
I'm not 100% convinced either

 

[Besoeker]

look at its construction, large permanent magnet
basically runs as a synchronous machine

Yes, I did wonder about that possibility.
We made permanent magnet, brushless machines. These were high speed, low inertia mainly for the machine tools industry in the aircraft manufacturing sector.
They were very small for their power rating - up to 200kW - the high speed, typically upwards of 20,000 rpm and water cooling meant they could be.

But they were three phase, not single phase.

 

[Jraef]

The "Written Pole Motor" concept has been around for a long time now, it was developed down the road from me at the EPRI (Electric Power Research Institute) in conjunction with a company in Florida called Precise Power. I don't know who this other company is in that link, likely a knock-off or spin off, but Precise Power owns a trade mark on the term "Written Pole" and this other outfit uses that term, so if it's not a collaboration, it's a lawsuit waiting to happen...

If you are interested in learning more, here's a slide show presentation on the technology done by a PE from from the EPRI, Lee Layton.
https://pdhonline.com/courses/e299/e299content.pdf

I've seen them in operation at a demo at the EPRI maybe a decade ago or so, they work fine, but yes, they are much bigger than the same HP rating in 3 phase, and they are EXTREMELY expensive. But in many of our (North American) far flung rural places, the utilities will not run 3 phase power at all; they will run single phase, even if it is for large motors. So this is actually a viable solution in those cases. I had no idea the market could support TWO manufacturers though...

 

[Ingenieur]

The "Written Pole Motor" concept has been around for a long time now, it was developed down the road from me at the EPRI (Electric Power Research Institute) in conjunction with a company in Florida called Precise Power. I don't know who this other company is in that link, likely a knock-off or spin off, but Precise Power owns a trade mark on the term "Written Pole" and this other outfit uses that term, so if it's not a collaboration, it's a lawsuit waiting to happen...

If you are interested in learning more, here's a slide show presentation on the technology done by a PE from from the EPRI, Lee Layton.
https://pdhonline.com/courses/e299/e299content.pdf

I've seen them in operation at a demo at the EPRI maybe a decade ago or so, they work fine, but yes, they are much bigger than the same HP rating in 3 phase, and they are EXTREMELY expensive. But in many of our (North American) far flung rural places, the utilities will not run 3 phase power at all; they will run single phase, even if it is for large motors. So this is actually a viable solution in those cases. I had no idea the market could support TWO manufacturers though...

that's the article I read
he must have something to do with it, I mean pdh course on something so obscure?

is he the guy with the weird 1 ph to 3 ph xfmr config?

it might be more plausible if they had 3rd party testing done to nema stds

I live in a rural area and if you pay you can get 3 ph

that monster still can't be cheaper than a vfd for conversion
not to mention off the shelf availability lol

whats a 100 hp 3 ph motor weigh?

 

[ptonsparky]

1300 lbs give or take

 

[kwired]

whats a 100 hp 3 ph motor weigh?

enough you will want a lift/crane of some sort to handle it

 

[GoldDigger]

is he the guy with the weird 1 ph to 3 ph xfmr config?

I would rather call it 3ph to 1 phase with fully balanced loading on the three source phases to a single phase output.
But that was Hugh Leyton. http://wpedia.goo.ne.jp/enwiki/User:Hugh_Leyton/sandbox

 

[Ingenieur]

I would rather call it 3ph to 1 phase with fully balanced loading on the three source phases to a single phase output.
But that was Hugh Leyton. http://wpedia.goo.ne.jp/enwiki/User:Hugh_Leyton/sandbox

gotch ya
similar name 'lee layton'
thnx

 

[Besoeker]

The "Written Pole Motor" concept has been around for a long time now, it was developed down the road from me at the EPRI (Electric Power Research Institute) in conjunction with a company in Florida called Precise Power. I don't know who this other company is in that link, likely a knock-off or spin off, but Precise Power owns a trade mark on the term "Written Pole" and this other outfit uses that term, so if it's not a collaboration, it's a lawsuit waiting to happen...

If you are interested in learning more, here's a slide show presentation on the technology done by a PE from from the EPRI, Lee Layton.
https://pdhonline.com/courses/e299/e299content.pdf

I've seen them in operation at a demo at the EPRI maybe a decade ago or so, they work fine, but yes, they are much bigger than the same HP rating in 3 phase, and they are EXTREMELY expensive. But in many of our (North American) far flung rural places, the utilities will not run 3 phase power at all; they will run single phase, even if it is for large motors. So this is actually a viable solution in those cases. I had no idea the market could support TWO manufacturers though...

It's one of the things I like about this forum - one learns new things.