oliwb
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| posted on 27/3/17 at 09:39 AM |
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3-phase Compressor on single-phase?
So, I've got the opportunity to buy a compressor from my employer very cheaply (we're moving buildings and it's basically going to
go in the bin / broken into spares if I don't want it). Obviously I'd love a 15Kw screw compressor (it's a nice one and has had
little use). But, I don't have 3-phase.....I've read a little bit about rotary phase converters etc. These seem expensive, especially at
the size I would need. I've also read that some 3-phase motors can be re-wired to work on single phase at lower outputs. Attached is a photo
of the nameplate for the motor. It does appear that you can wire in both star and delta. But with such a big compressor is it even possible to run
on 230V? I understand that it'dd suck a good deal of power on startup so maybe that's where it'll come unstuck? I'm begining
to think it's more hassle than its worth.......
Appreciate any insight from people who know what they're talking about!
 
Motor plate
If your not living life on the edge you're taking up too much room!
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furryeggs
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| posted on 27/3/17 at 11:53 AM |
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Single phase to 3 phase inverter. We use them a lot at work, and are fairly straight forward to wire up. Siemens and Mitsubishi do some good ones that
you might be able to find relatively cheap?
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David Jenkins
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| posted on 27/3/17 at 02:05 PM |
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Can you use an inverter on a 3-phase compressor? I'd heard/read/got from a bloke down the pub that compressors are fairly brutal on start-up,
and might be too much for an inverter.
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dinosaurjuice
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| posted on 27/3/17 at 03:11 PM |
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More hassle than its worth. Better off selling it to find a purpose built single phase compressor IMO.
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David Jenkins
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| posted on 27/3/17 at 03:32 PM |
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I wasn't far wrong: Phase Converter Info
Basically, static converters (the cheaper ones) can't drive a compressor as the initial load is too high, and too different from the running
load. This means that the converter can't be matched to the compressor. A digital converter can do the job, but they ain't cheap.
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RedAvon
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| posted on 27/3/17 at 05:45 PM |
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Hi,
Looking at the motor plate, I am not sure it is a dual voltage motor, as it only states a 3 phase voltage. I understand you need a dual voltage motor
to run it off a 3ph to 1ph inverter drive.
Ian
Bricoleur
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ChrisW
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| posted on 27/3/17 at 06:25 PM |
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I have three phase in my new workshop if you fancy donating it? 
Chris
My gaff my rules
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mark chandler
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| posted on 27/3/17 at 06:32 PM |
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28amps @ 415v
It's a non-starter in more than 1 way I am afraid.
Grab it, eBay it get something a little smaller.
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coozer
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| posted on 28/3/17 at 08:41 AM |
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Change the motor to a single phase 240v one. Did that with my lathe, got the motor from machine mart.
1972 V8 Jago
1980 Z750
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David Jenkins
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| posted on 28/3/17 at 09:22 AM |
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Sounds like it's a big compressor - it'll have to be a bl**dy big single-phase motor, and even then it may struggle.
A 3-phase motor is really good at starting against a load without overheating, and will tolerate repeated starts (as you'd get with a compressor
with an automatic pressure switch). Single phase motors have a starting winding and don't like to start against a heavy load as this would
prevent the motor getting up to speed quickly; the starting winding will be in circuit far longer than it ought to be and it will overheat. Repeated
starts will also cause the motor to overheat as the starting winding doesn't get a chance to cool down.
A lathe is an easy load compared to a compressor as it can be wound up very quickly - a compressor is on full load as soon as power is connected.
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Toys2
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| posted on 28/3/17 at 09:23 AM |
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quote:
Originally posted by coozer
Change the motor to a single phase 240v one. Did that with my lathe, got the motor from machine mart.
Probably not practical to do as you'd need to size the motor for the load, based on the 3 phase rating, a single phase motor would be way too
large
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