AWGB Woodturning Forum

General Category => General Discussion => Topic started by: vyvsdad on August 01, 2013, 12:41:33 PM

Title: 3 phase motor help
Post by: vyvsdad on August 01, 2013, 12:41:33 PM

Hello all,

I'm not sure if this is in the right section, so feel free to move it mods.
I have designed and intent to build my own bowl lathe. I have drawn it up, got all the metal parts together, have a friend who is an engineer lined up to help me with any milling etc that might be needed, but I'm having trouble with the motor.

I have been given a 5hp 3 phase electric motor (which my be over egging the pudding a little, but nevermind). The problem I have is that it is just the motor, no starter, no wires, no cables, and I draw a blank when it comes to all things electric. I'm assured that the thing runs and runs well. I intend to have several pulley options as well as a dial for speed control

So, can anyone recommend me some good books on the subject, or some good companies/people whose brains I can pick, or just tell me whether or not you think I should carry on with this bare motor or just buy one complete.

Any help anyone could give me would be brilliant.

Thanks in advance.

Dan

Title: Re: 3 phase motor help
Post by: BarryMobbs on August 01, 2013, 01:31:09 PM

Hello Dan,
 
 in order to use your motor you will need a three phase supply which is unlikely if you are in a domestic environment.
 A three phase 240V output can be obtained using a single phase variable speed drive (inverter) but one of these to drive a 4kW motor would be relatively costly. This would of course only be an option if the motor is wound for 240/415V.
You are unlikley to need more than 1.1/1.5kW so I suggest you forget the big motor and go for something smaller. If you want variable speed, a small three phase motor would be best with a single phase input inverter both of which can be obtained at relatively low cost (but you would need someone to connect and set it up for you).   

  Barry

Title: Re: 3 phase motor help
Post by: vyvsdad on August 01, 2013, 01:38:15 PM

Thanks for the reply.
The thing is, I do have a 3 phase supply, so what with being given this motor, I thought I'd take advantage of it.

Title: Re: 3 phase motor help
Post by: TONY MALIN on August 01, 2013, 03:23:28 PM

3 phase motor on 3 phase supply GOOD.
5hp motor for 1/2 hp required BAD. Will run at a very low power factor and
your power company probably won't like it. You'll also get a high switch on current so need to check your wiring.
Strongly recommend you seek professional help.

Title: Re: 3 phase motor help
Post by: vyvsdad on August 01, 2013, 07:23:58 PM

I think I need more than 1/2 hp though.
When I say a bowl lathe I mean a big bowl lathe, as I have regular access to BIG bits of wood and wanted to try my hand at something big with out spending a fortune.
Most commercially available bowl lathes that are equivalent to what I intend to build seem to be 2 hp or more. I freely admitted that 5hp was perhaps too much. Thank god I turned down the 10hp one.

Maybe I'll put my current motor on ebay and look for a smaller one.

Thanks for your help.

Title: Re: 3 phase motor help
Post by: Bryan Milham on August 02, 2013, 04:05:57 PM

Contact Hughie (of this forum).

He has built (and builds) big Bowl lathes - He'll help you out with all the ideas you'll need to start you off and then guide you.

Title: Re: 3 phase motor help
Post by: BarryMobbs on August 03, 2013, 08:45:01 PM

Hello Dan,

 If you are fortunate enough to have a three phase supply you have no problem.
 I would suggest you use an inverter drive which will give you a wide speed range.
 The motor will only produce 4kW if you load it that much, for most work the power consumption will be much lower.

  Regards,  Barry