Do hobbyists use 460V 3-phase rotary phase converters?

[Rotaretard]

In trying to sell a used 120hp, 460V RPC, someone said the only application he knew would be an individual running industrial machinery out of their garage. Is this common? It's seems a little overkill. The other RPC's discussed on this site are like 7.5HP.

And if so, are there middlemen that hobbyists/artisans buy RPC's from that I could sell it to? It's listed online, but I'm a little tired of hearing crickets. Electrical surplus stores and electric motor parts/repair stores don't want it either.

 

[mike93lx]

There is no residential service that can support that.

Other than getting really likely finding a maintenence manager on a tight budget, it's best value is in scrap. But even for the first scenario, I think any value would be in the motor itself, not as a rpc

 

[cvairwerks]

Anyone that needs one that big, is not a hobbyist and they are going to be on 3 phase already.

 

[loganb]

There is no residential service that can support that.

Other than getting really likely finding a maintenence manager on a tight budget, it's best value is in scrap. But even for the first scenario, I think any value would be in the motor itself, not as a rpc

This

 

[cannuck]

What is the OP's converter supposed to convert? Anything on 440-480 is already 3 phase. Could it be a 60 to 50 cycle M/G set?

 

[mike93lx]

What is the OP's converter supposed to convert? Anything on 440-480 is already 3 phase. Could it be a 60 to 50 cycle M/G set?

Looking at the username and profile, this feels like a troll or one and done anyway

 

[cannuck]

Looking at the username and profile, this feels like a troll or one and done anyway

Wouldn't want him to go away without hearing the story behind what this is supposed or assumed to be.

 

[u3b3rg33k]

why would a 120HP RPC exist?

 

[micromind]

I did some electrical work on a small oil refining plant several miles from a 3Ø power line. The PUCO ran single phase (7200 volts) out to the plant and set a 167KVA 480 volt single phase transformer. The plant had several pretty fair-size phase converters.

 

[dscheidt]

why would a 120HP RPC exist?

It's a whole lot cheaper to run a single phase at higher voltage than three phase, so there are remote sites like mines that have three phase loads that needed big phase converters.

 

[wyliesdiesels]

In trying to sell a used 120hp, 460V RPC, someone said the only application he knew would be an individual running industrial machinery out of their garage. Is this common? It's seems a little overkill. The other RPC's discussed on this site are like 7.5HP.

And if so, are there middlemen that hobbyists/artisans buy RPC's from that I could sell it to? It's listed online, but I'm a little tired of hearing crickets. Electrical surplus stores and electric motor parts/repair stores don't want it either.

as said above, you will not be able to run that on a residential service.

good luck finding a buyer

 

[American Locomotive]

Some farms way out in the middle of nowhere are provided with 480v single phase as well. As mentioned, cheaper to run two wires than three.

They would have a big RPC to run everything.

I'm not sure if they still do, but some motor manufacturers at one point actually made 480v single phase motors, too.

The market for this RPC is basically zero. I would assume just about everyone who needs an RPC of this size already has one. You might want to try reaching out to an industrial equipment broker/reseller. They may be willing to purchase it. You won't get as much, but some money is better than zero money.

 

[Stuart in MN]

Looking at the username and profile, this feels like a troll or one and done anyway

Their profile says they are in Sierra Leone?

 

[RoninB4]

-I don't have 3 phase and I'm not a commercial enterprise. I'm running 460/480 for my jig borer in the basement on an RPC and step up transformer. I have several other 3 phase industrial machines in the basement as well. Some folks want the benefit of industrial machinery but just don't have 3 phase. The target market is much smaller than the average suburban Harry Home-shop but there is still an audience looking for what the OP wants to sell.

 

[mike93lx]

-I don't have 3 phase and I'm not a commercial enterprise. I'm running 460/480 for my jig borer in the basement on an RPC and step up transformer. I have several other 3 phase industrial machines in the basement as well. Some folks want the benefit of industrial machinery but just don't have 3 phase. The target market is much smaller than the average suburban Harry Home-shop but there is still an audience looking for what the OP wants to sell.

Sure. But a 120hp rpc? No one is running that in a home shop

 

[RoninB4]

Sure. But a 120hp rpc? No one is running that in a home shop

-I failed to notice the 120hp on the RPC.....

 

[cannuck]

Fantastic to learn something new every day around here. I could not have imagined any place running single phase in and converting on site, so what the OP refers to now makes some kind of sense. Would have to be very remote to justify doing this to save just one conductor. Not only that, but a large load on one leg could drive a utility to swear. Most sites I work in are well served by all 3 wires of utility (or 2 wires to converter stations at end of 460KV "DC" - same idea as post 9, 10 and 12, but at 1,000x the voltage) but in most cases where main power feed needs to be protected (usually from corrosive gases or fallout) we see 4 conductors burried beside each other so a failure of 1 becomes a quick swap to the spare so a major repair can be done on scheduled outage.

 

[PCustoms]

Their profile says they are in Sierra Leone?

Report the spammer....

 

[purplezr2]

Be curious to see pictures

 

[u3b3rg33k]

i hear you about single phase being cheaper but in practice an open delta isn't much more expensive and gets you way more capacity. i guess it depends on where the distribution voltage is coming from?

is it 7.2kV SWER?

 

[American Locomotive]

Open delta still requires 3 wires. Your only savings are that on either end, you have one less transformer (in a 3 phase transformer bank)

But when you're running an electric service 300 miles from the nearest utility pole to Nowhere, Kansas; being able to run 2 wires instead of 3 will save you hundreds of thousands, potentially even millions of dollars.

 

[Bert_]

I deal with this kind of thing pretty regularly on farm grain sites. Not uncommon for three phase to be miles away. Several years ago the cost rebuild primary and bring three phase to a property was $80,000 a mile.

I have installed a couple 480 volt single phase services and a ton of 600 and 800 amp 240 volt single phase services. Been doing more and more with vfds and feeding in single phase. I have done more than one site with a 75 hp motor plus many other smaller motors. on single phase service.

I've never seen an RPC with 120 hp idler but a lot of times the 60 hp ones will run 120 hp worth of motors.

 

[u3b3rg33k]

I deal with this kind of thing pretty regularly on farm grain sites. Not uncommon for three phase to be miles away. Several years ago the cost rebuild primary and bring three phase to a property was $80,000 a mile.

I have installed a couple 480 volt single phase services and a ton of 600 and 800 amp 240 volt single phase services. Been doing more and more with vfds and feeding in single phase. I have done more than one site with a 75 hp motor plus many other smaller motors. on single phase service.

I've never seen an RPC with 120 hp idler but a lot of times the 60 hp ones will run 120 hp worth of motors.

I got a quote recently for about 1/3 mile. I think it was 30k for big single phase and another 10k for 3ø. directional boring. considering just going off-grid instead. 40k buys a lot of equipment.

 

[dchawk81]

In trying to sell a used 120hp, 460V RPC, someone said the only application he knew would be an individual running industrial machinery out of their garage. Is this common? It's seems a little overkill. The other RPC's discussed on this site are like 7.5HP.

And if so, are there middlemen that hobbyists/artisans buy RPC's from that I could sell it to? It's listed online, but I'm a little tired of hearing crickets. Electrical surplus stores and electric motor parts/repair stores don't want it either.

Damn I just bought 3. Too bad you didn't post at 10:00 instead of 10:06.

 

[wyliesdiesels]

i hear you about single phase being cheaper but in practice an open delta isn't much more expensive and gets you way more capacity. i guess it depends on where the distribution voltage is coming from?

is it 7.2kV SWER?

open delta has nothing to do with 2 or 3 primary wires. open delta means only 2 transformers are feeding the secondary service vs 3. so the available 3 phase current is 1/3 less. its purpose is to save the PoCo money on transformers, cutouts, fuses and wires. but means less power available to customer.

you still need 3 primary wires as you can feed any transformer bank with 2 wires and a neutral, if theyre rated for the proper primary voltage

 

[Steve from Socal]

I get the single phase 480 service, the 120 HP converter was likely for a particular machine. That HP rating is kinda telling.

That said, a mentioned YES some folks DO use 480 three phase in hobby shops.

 

[Balvar24]

I built/rebuilt a 25 HP rotary phase converter that someone had kludged together. I use it to run a 10 HP air compressor. Both were free or I would have done something else because it's really more trouble than its' worth. I wanted to see if I could do it.

I bet the capacitors it takes to correct a 120HP are huge. Good luck. I'd say your 30 years to late to the party.

Maybe if you found someone with a really really big boat in need of an anchor?