American Bristol 18CFM Compressor

[kancho]

I got a 18CFM American Bristol compressor. It has a 3 phase motor in it. Is it possible to hook it up to a 220 1 phase? Will it even work? it is a 220/440 3 phase 15 hp motor.

If it does will that lower the final pressure or the CFM? Sorry I am a newb.. And I just want to know is it worth calling in an electrician to get a 3 phase wiring. I really don't need 18 cfm..

 

[cool_hardware52]

I got a 18CFM American Bristol compressor. It has a 3 phase motor in it. Is it possible to hook it up to a 220 1 phase? Will it even work? it is a 220/440 3 phase 15 hp motor.

If it does will that lower the final pressure or the CFM? Sorry I am a newb.. And I just want to know is it worth calling in an electrician to get a 3 phase wiring. I really don't need 18 cfm..

I have one of these compressors. I operate it from 480 volt 3 phase. (I have a 400 amp 480 service so it's easy for me to do so)

15 hp single phase motors will be 1) Rare, 2) Very very very expensive.

If you could find a 15 hp single phase motor you probably do not have enough electrical service capacity to operate it.

15 hp = 11190 watts. At 220 volts that is over 50 amps! If the motor is ~70% efficient you need about 70 amps to run the motor, and that does not include the much higher starting current.

If you are in a commercial area you **could** investigate having a 3 phase service installed. Not cheap, new drop from the pole, new meter, new panel etc.

"Homeowner" compressors are usually limited to about 5 hp for the reasons listed above.

Is it possible to run your pump at 1/3 the rpm with a 5 hp motor? I doubt it. Even if it was you need a new motor, (maybe a new motor mount) a new set of sheaves, new belts and some mods to the electrical controls.

The real answer is to sell your pump to somebody who has access to three phase and use the proceeds to buy a more practical pump.

The reason I have a 15 hp, 18 cfm compressor is it was reasonably inexpensive. Why? because most users cannot practically power it.

Good luck,

Tobin

 

[mike_s]

I just want to know is it worth calling in an electrician to get a 3 phase wiring.

after you get the quote from the electrician and they get you up off the floor from shock, then let us know...

the last person I know that had their primary service on the building changed from single phase to 3-phase cost I think about $6k to change it out. (new meter, new panel, re-installing all new breakers, new line running to the outside pole, etc).




3 phase just cost more....

Everything I do at work is 3-phase. (but I don't see the overall costs because we have staff electricians and I never see a "full bill".)

but 3-phase breakers cost on average $80 to $100 bucks each compared to single phase 220v breakers running $5 to $10 each. just something to consider for comparison purposes.

most of my 3 phase connectors run about $60 to $80 bucks each (HBL-2811 and HBL-2813's) for example. (even though I think we've bought them as cheap as $30 bucks before)

I really don't need 18 cfm..

Best thing you can do is to try to swap that to someone who can use it and can power it. swap it for a smaller compressor setup for someone wanting to "trade up".

Or... find a friend who owns commercial property with 3 phase service that will let you have a corner to use and pay him some electricty money with beer.

 

[Thadmn]

It's possible to run it using a rotary phase converter that you can build yourself, if you are somewhat electrically/mechanically inclined. It involves swapping capacitors around in order to achieve the right voltage balance. Hopefully you have a surplus store around that you can buy the parts from. I have an article on how to do it. If you want me to e-mail it, PM me. Also, you could go with a gas motor if you're careful.

 

[mike_s]

It's possible to run it using a rotary phase converter that you can build yourself, if you are somewhat electrically/mechanically inclined. It involves swapping capacitors around in order to achieve the right voltage balance. Hopefully you have a surplus store around that you can buy the parts from.

You can buy those already built... but I don't know if you can get one that will run a 15hp motor on single-phase. talk about having a huge breaker (single phase) to run that phase convertor....

 

[cool_hardware52]

It's possible to run it using a rotary phase converter that you can build yourself, if you are somewhat electrically/mechanically inclined. It involves swapping capacitors around in order to achieve the right voltage balance. Hopefully you have a surplus store around that you can buy the parts from. I have an article on how to do it. If you want me to e-mail it, PM me. Also, you could go with a gas motor if you're careful.

Solid state (cap type) phase converters require reducing the name plate hp by 1/3, in other words a 15 hp 3 phase motor will be effectively 10 hp if operated on such a device. This will require new sheaves and belts.

A "true" rotary phase converter will allow the motor to deliver full nameplate hp, but the cost is much much higher.

The fact remains, that the existing electrical service is very likely to be insufficient to operate a 15 hp motor.

I recommend starting with an investigation of the existing service. Very few single phase services are "sized" for the operation of large loads. The cost of upgrading a single phase service from say 100 amps to 200 amps will be less than having three phase installed, but it will still be expensive.

There is a reason one almost never see's "home owner" compressors greater than about 5 -7.5 hp, you just can't power them from the typical residential single phase electrical service.

Tobin

 

[kancho]

Is it even possible to swap out the 15hp motor and put in a 7.5 phase 1 motor? Will it work. Yeah getting a phase 3 power line is expensive. I called some electricians and they don't want to do it. haha.

Rotary converter I saw some on ebay. Do I need a motor to run my compressor motor? That is what I am reading.

 

[cool_hardware52]

Is it even possible to swap out the 15hp motor and put in a 7.5 phase 1 motor? Will it work.

Have you read my posts?

Yeah getting a phase 3 power line is expensive. I called some electricians and they don't want to do it. haha.

Rotary converter I saw some on ebay. Do I need a motor to run my compressor motor? That is what I am reading.

Step one is to verify if you have enough POWER AVAILABLE from you current electrical service to power a big motor.

If do have enough power available (amps) you can start to worry about:

1) Just how big a motor

2) Single phase or three phase

3) Solid state or rotary converter or VFD.

If you don't know what these are you will need to hire somebody to select the right one and install it. This will cost more than a nice 5 hp single phase compressor.

Tobin

 

[dannobee]

If your intent is to keep it, look at getting a gas or diesel engine for it instead of electric power. 15-20hp small engines are a lot cheaper than upgrading to three phase. Keep the big motor in case you sell it to someone with the correct power available.

 

[kancho]

Ok Will this work? Can anyone tell me

Use a 15.5 hp Gas Engine with Electric Start,
Remove the old motor and magnetic starter.
Remove the Transformer and put a new 120Vac breaker to power the electric
Add a governer for the gas engine to start/stop

Can anyone tell me if I am missing something.
This can be done for about 400 inparts

Called 3 electricicans all didn't want to deal with 3 phase
300 dollars minimum to put a new breaker in for 220 volt single phase.

Any thoughts?