Help with 3 phase cable options

[El Campo]

My shop is fully wired with single phase but recently bought a bunch of equipment that requires 3 phase of different voltages. I know little about AC wiring. I am 350 feet off of a 3 phase line that I could have the electric company put a disconnect on and then they would rerun wiring to my shop for the price of 5000 dollars. I would still have to have electrician set up everything in the shop. My other option may seem a bit wilder but may be cheaper? We have 3 phase actively in a meter and running some equipment 1000 feet away. Can I just hook into that 3 phase with a direct burial cable and bury it up to my shop and then put a breaker box there with my individual circuits off of that? The largest load is a 15 hp compressor. Will have a max of 75 hp at one time being used. What size of cable would I need? My head is spinning from all the wire options available. Also some of the machines run off of 480 and some are 240. I would need a step up or step down transformer correct? Any help is appreciated.

[franken]

What's the voltage on the power 1k' away? A step up transformer cuts available current by the ratio of the increase, so that's probably not a viable option.

[truckdude239]

If you need 480 might be best to have a 480 volt service put in . All our cawasg equipment at work runs on 480 and we have to have its own service

[DPowers]

My dad set up his wood shop to run on 3 phase for years. He had 220 single phase and then used capacitors and another motor that he kicked in that gave the 3rd leg. Just used it tonite. I don't know how he did it exactly and he passed away away 3 years ago, so no help there, but I know it can be done.

[dwcsr]

look into a phase generator

[A1971Blazer]

I ran my entire machine shop on a rotary converter years ago before 3ph was available near me.

I can't remember where I got it but it had a 30hp motor and was balanced between all 3 legs to ±5% voltage. This set up worked really well and I ran several CNC machines on it.

As far as running 480 on a 220 input.......not so sure you can step up that much? Most motors can be configured to run on a lower voltage by changing the input leads at the motor. If it can, there will be a wiring schematic on the motor tag.

[El Campo]

I will check what our current voltage is 1000 feet away and post back. I've looked into phase converters but will be running a 7000 dollar plasma cutter and have not been able to get a good answer about how that will work with a convertor.
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[A1971Blazer]

Originally Posted by El Campo

I will check what our current voltage is 1000 feet away and post back. I've looked into phase converters but will be running a 7000 dollar plasma cutter and have not been able to get a good answer about how that will work with a convertor.
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I ran a $75,000 CNC machining center on mine.....

[Willie Makeit]

i ran 2 CNC machines (a 10" chuck Okuma lathe and a 40"x20" Okuma VMC) and a huge DoAll band saw on one single Rota-Phase rotary converter. As described above, we used 240 VAC single phase input to the converter and it generated the 3rd leg by way of a "pony motor" (as the old guys call 'em ) We never got a single alarm from the CNC's for voltage irregularities in the 5 years we ran them that way. Not one. The voltage never exceeded /fell below +/- 5%.

We too had 3 phase power available to our shop, and it was less than 50 ft away and the local municipality wanted $10K to hook us up! We went with the rotary phase converter for less than half.

Made a ton of money and fed my family off that set up.

[El Campo]

Good information here. I could be wrong but wouldnt a plasma cutter than cuts at 100 amps pull more than the typical CNC machine though? The biggest phase convertor I have found is a 30 hp idler motor and that only supports something like 20 hp. My one air compressor alone is 15 hp and I have 3 of them. Plus a big mill and lathe. Plasma that will cut over 2 inches and the list goes on. I know that I can prob piece together a 30 hp motor phase convertor setup for about a thousand dollars but there is no way one 30 hp convertor would run everything. Or am I missing something?

[DPowers]

My dad told me that the machines will add to the voltage somehow and "feed" each other when they are running.

[_Ogre]

1000 feet is a bit more than you want to bury, I think you'd be shocked at the price
150 amp with a 1000 foot voltage drop would probably be 4 ought (0000) wire
150 amp is not doable with a phase converter, so pay up

Most 3 phase equipment can be used on 480 or 240 volts,
it's a matter of how you connect the equipment
Rarely equipment is only one voltage

[BR3W CITY]

When I was with a mech contractor, we used to have a guy that made little shop-rigged "phase convertors" I think he called them. They worked well for 3-phase only older shop equipment (pre 40's lathe's and mills).

I'm really scratching the back of my memory, but it works because if you spin-start a 3phase lathe, you can still power it on 2 phase, but lacking the work energy to start the tool from a dead stop.

*truth be told, I don't know enough about what I'm repeating in this case to actually explain any of it.

[BigDan3131]

Have you ever thought to just sell off some of the equipment and upgrade to better powered stuff? Specifically the air compressors, one very large rotary vane type should be more than enough to do everything you need and save you money since the newer tech stuff is more energy efficient.

[bdiamond]

I would think 5 grand for the power company to get you going would be the cheapest route. 3 thousand feet runs of 4/0 would be a chunk anyway. Pulling 1000 ft run wouldn't be easy either....