Compressor motor

[Graham schofield]

Been looking at a compressor upgrade for a bit now and I've seen a few 3 phase compressors a hell of a lot cheaper than single phase so was wundering if I got a 3 phase belt driven conpressor and changed the motor for a single phase is it as easy as that or is there more to it I no there is less to go wrong with a 3 phase motor but don't want to start messing with converters and all that.

Or if any one can tell me an easy free way of running a 3 phase motor on 1 phase feel free to let me no

Thanks

 

[brightspark]

your only going to get a 4hp motor max off single phase supply

 

[dobbslc]

And finding a second hand 3 or 4 hp single phase motor is hard.....
But if anyone's got a 3hp going cheap ....

 

[Graham schofield]

An going to have a chit with the fitter in work he has 2 steel filing cabinets full of motors as he takes the single phase ones off and replaces them with 3 phase because that are man tens free only thing to go wrong is bearings go plus all are machines are 3 phase he may swop me a 3 phase for a single phase

 

[Graham schofield]

So if I find a 3hp belt driven compressor and change the motor for a single phase motor it will work ?????

 

[roofman]

So if I find a 3hp belt driven compressor and change the motor for a single phase motor it will work ?????

yes...just make sure it matches the rpm for the pump. big pumps normaly run the 1425 rpm

 

[Graham schofield]

So I am best seeming what motor I can get 1st then and going from ther??

Is it easy to get a 3 phase motor to run off single phase

 

[brightspark]

[

So I am best seeming what motor I can get 1st then and going from ther??

Is it easy to get a 3 phase motor to run off single phase

no and inverters dont like the starting current on compressors under load

 

[roofman]

So I am best seeming what motor I can get 1st then and going from ther??

Is it easy to get a 3 phase motor to run off single phase

ime confused now...do you want to swap a 3 ph for a single ph?

 

[Graham schofield]

Thanks we'll see what motor I can find 1st then take it from there

 

[Bsmith]

your only going to get a 4hp motor max off single phase supply

Dam, hate to say different to this fella because he knows his stuff.
I had a compressor that I ran for years on a 5hp single phase motor. A spark wired it for me, relay to solenoid after pressure switch if I remember right. It certainly dimmed the lights when starting on load but as I say, worked well for years. Eventually changed to a different set up and motor. Sold the 5hp to Eil, havnt seen him on here for a while.

 

[brightspark]

Dam, hate to say different to this fella because he knows his stuff.
I had a compressor that I ran for years on a 5hp single phase motor. A spark wired it for me, relay to solenoid after pressure switch if I remember right. It certainly dimmed the lights when starting on load but as I say, worked well for years. Eventually changed to a different set up and motor. Sold the 5hp to Eil, havnt seen him on here for a while.

Dam, hate to say different to this fella because he knows his stuff.
I had a compressor that I ran for years on a 5hp single phase motor. A spark wired it for me, relay to solenoid after pressure switch if I remember right. It certainly dimmed the lights when starting on load but as I say, worked well for years. Eventually changed to a different set up and motor. Sold the 5hp to Eil, havnt seen him on here for a while.

quite right .lot of farms run a 5hp motors on there mills.they have a start and run manual starter to run them up 2 speed

 

[dannyp]

i've seen meany 6 hp brooke motors on feed mills

even got one in the shed and it's a monster of a thing, i can just about drag it, 1" 5/8ths shaft out of it, and made in the 50's as bright spark said they have sepearate starter box, with manual changeover for start and run.

the supriseing thing about these old singel phase motors is how well they run, startup current is very low compared to a lot of modern singel phase motors, last 5hp cheapnease motor i had would throw a 40A breaker regualy. needed a 60A breaker to wind up a load with relativly littel inertia and would knock out all the floresents for a moment. the brook motor used to wind up a feed mill and later on a compressor without so much as a flicker on the lights and on a 20A beaker

 

[eil]

Dam, hate to say different to this fella because he knows his stuff.
I had a compressor that I ran for years on a 5hp single phase motor. A spark wired it for me, relay to solenoid after pressure switch if I remember right. It certainly dimmed the lights when starting on load but as I say, worked well for years. Eventually changed to a different set up and motor. Sold the 5hp to Eil, havnt seen him on here for a while.

Still here Bernard and as you say that was a 5hp single phase.

 

[Bsmith]

Still here Bernard and as you say that was a 5hp single phase.

Good to see you again eil, have you got the motor in use?