Three Phase?

whisper · 15 February 2013, 17:48

Hummm, found a nice newish and very large compressor in my late fathers workshop but it's three phase, next to it is a 240v to three phase converter with a motor attached.

Now here is the question, is it worth keeping and trying to work out how to connect the two together or selling both and get a 240 v one.

simsy · 15 February 2013, 17:54

Your inverter is 230volts input single phase and 220 volt three phase output.

So you compressor motor must be able to run 220vac 3 phase also . Most motors can be set into delta to run at 220vac three phase . I suspect that you compressor motor is too large for the inverter you have... Check your motor size against the inverter size also... I.e. kw rating and/or current rating.....

You can buy converters to run 400volt three phase motors from 230v single, see them on eBay...

Post up photos of the motor and inverter labels and I can tell you more...

whisper · 15 February 2013, 17:59

I remember him saying it is the attached motor which generates the 3rd phase if that sounds right.

Is three phase normally 415v or something like that?

Ian M · 15 February 2013, 18:03

Quote:

Originally Posted by whisper

I remember him saying it is the attached motor which generates the 3rd phase if that sounds right.

Is three phase normally 415v or something like that?

Mmm, doesn't sound right to me. Yes 3 phase is normally 415V. As Simsy says, check the ratings.

simsy · 15 February 2013, 18:07

Euro norms are 400v three phase. I.e. yep 415v

whisper · 15 February 2013, 18:16

There are several machines in there and my dads wishes were for me to sell and everything I wasn't going to use and give the money to me mum and i really can't see me using a milling machine or a metal working lathe although the horizontal bandsaw looks handy....

I'll have a look tomorrow.

mister p · 15 February 2013, 18:31

Wire the bugger up, plug her in, see what happens. Isolate it with a fuse though.

whisper · 15 February 2013, 18:34

Quote:

Originally Posted by mister p

Wire the bugger up, plug her in, see what happens. Isolate it with a fuse though.

There is no way I'm diggin me dad up!

Ian M · 15 February 2013, 18:35

Quote:

Originally Posted by mister p

Wire the bugger up, plug her in, see what happens. Isolate it with a fuse though.

Er, NOT a good idea.

Peter_C · 15 February 2013, 18:38

If the converter is not the right one, you could always just swap the motor out. I did that for my scuba compressor as three phase motors with a converter will draw more power than single phase motor...but barely. It maters to me since I often run my compressor for 4 hours at a time. Plus a converter was around the same cost as a new motor.

I have been looking for a milling machine, too bad shipping isn't feasible. Did your dad ever teach you how to run the equipment?

whisper · 15 February 2013, 18:45

No, he bought it all but never used it. Some stuff is outside and would be hard work to restore but the stuff inside is ok.

Anchorhandler · 15 February 2013, 18:59

Alex
If your fathers converter looks like it has a motor attached to it then its most probably a 'rotary converter' which uses a donkey motor to create the third phase. This is good news as rotary converters (contrary to static converters) produce a very good quality sine wave...not perfect but very good never the less.

You need to check the input Kw rating of the compressor motor and then compare this to the output rating of the converter...if the converter rating is higher by at least 10-15% then you should be OK to use it to drive the compressor.

You will more than likely need a 16amp (minimum) single phase supply for the converter though although this depends obviously on the output power rating of the converter itself.

What make is the compressor BTW?

Simon

whisper · 15 February 2013, 19:04

Hummm... its three words and it has industrial in it and its blue.

whisper · 15 February 2013, 19:14

Quote:

Originally Posted by whisper

Hummm... its three words and it has industrial in it and its blue.

Got some pics on my phone, not really of the compressor but it can be seen in the background.

I want to keep anything I can use for rib stuff

mick · 15 February 2013, 19:39

Stick to the grinder you could put some polishing discs on for stainless
And the band saw

Chris · 15 February 2013, 20:11

Quote:

Originally Posted by whisper

Got some pics on my phone, not really of the compressor but it can be seen in the background.

I want to keep anything I can use for rib stuff

Fook me is that a 3 phase bench grinder

Anchorhandler · 15 February 2013, 20:24

Quote:

Originally Posted by whisper

Got some pics on my phone, not really of the compressor but it can be seen in the background.

I want to keep anything I can use for rib stuff

Looking at the colour, it looks like a Clark industrial compressor....they're not bad.....for the money.

The small Sip band saw is worth keeping, especially if your into fabricating stuff...makes cutting lengths of steel so much quicker and neater.

The bench grinder is old but probable still much better than the stuff you can buy nowadays (made in China shite...unless you want to spend big money of course).. the lathe looks like possibly an old Myford which could very well fetch a few hundred quid if you sold it.

What did your Dad do?

Simon

whisper · 15 February 2013, 20:52

He was an 'old school' engineer, you know the 7 year apprenticeship type

Drove me insane that we had to build a machine for a couple of weeks to do a job that would have taken us 5 mins

But it was like growing up in the A Team.

He retired through ill health due to his heart and was very frustrated at home but he wanted to build the best workshop ever but filled it with projects.

Sadly he died just 4 weeks after he found out that he might have cancer. it's a tough challenge sorting stuff out, but I enjoy remembering the things we used to get up to.

A few days before he died I got his land rover and parked it next to the room where his bed was and we snuck out and I drove him round his field and showed him all his stuff. When he was asleep I had been out there cleaning up the place and he said he was so proud.

He said he had lots to tell me but he died two days later so he never had time.

Peter_C · 15 February 2013, 20:53

Quote:

Originally Posted by Anchorhandler

You will more than likely need a 16amp (minimum) single phase supply for the converter though although this depends obviously on the output power rating of the converter itself.

FWIW my 7.5HP single phase compressor motor pulls a continuous 18 amps, and 36 amps at start up. It is rigged on a dedicated 50 amp circuit.

mister p · 15 February 2013, 21:22

Oh for feks sake, wire the bugger up. If your lights go out it's wrong, if they dim then you're nearly there, if it keeps going then turn it all off and check it all in the morning.