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Forum Index : Other Stuff : F&P 3 Phase power

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Rastus

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Joined: 29/10/2010
Location: Australia
Posts: 301
Posted: 05:43am 24 Jun 2014
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Hello to all members,
I thought I'd test the waters to gauge how viable generating 3 phase power with F&P motors could be. Usefull industrial machines that run on 3 phase power are fairly plentiful and relatively cheap at the moment. I don't want to outlay capital to install 3 Phase to my property and only use it occasionally. I have a couple of petrol engines laying around and a number of F&P motors. Reportedly F&P, in there original wiring state produce 400V 3 phase power with 3-4 amps output. If these were run at 3,000rpm I'm guessing I'd have 50hz. Some questions are, is the 400V 3-4 amp figure from a 100 series F&P? Or later motors? If yes, would it be necessary to rewire later series F&P to 1mm copper? Is it possible to increase the Voltage to 415V?
Any help appreciated!Kind regards Rastus
see Rastus graduate advise generously
 
Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5078
Posted: 12:39pm 24 Jun 2014
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Hi Rastus

A typical AC generator head has 2 poles per phase to produce 50Hz AC at 3000rpm ( I'm guessing here, its early and my brain isn't warm enough to do the maths. ).

A F&P has 14 poles per phase ( 42 total ). So at 3000rpm the output frequency would be like 350Hz ( Again, a guess, not doing the maths ). This is way to high to run anything designed for 50Hz AC. Also a F&P at 3000rpm would be making some seriously dangerous voltages, likely over 1000v.

If you slow down the F&P enough to get 50Hz, around 428 rpm, the output voltage would be somewhere between 100 and 200 volts, to low for 3 phase AC gear.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9306
Posted: 08:21pm 24 Jun 2014
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There are videos on YouTube of people putting F&P smartdrive motors on petrol engines, and the output they produce voltage-wise is extremely dangerous. Taking Glen's example, and assuming an output of at least three to four amps @ 1000v = dead.

It is actually remarkable, what those old smartdrive motors are capable of doing....

I have one here I was always gonna rewire as per the instructions elsewhere on The Back Shed, but have never got around to it.
Smoke makes things work. When the smoke gets out, it stops!
 
Rastus

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Joined: 29/10/2010
Location: Australia
Posts: 301
Posted: 04:43am 25 Jun 2014
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Thanks Glenn and Grogster,food for thought. Kind regards Rastus
see Rastus graduate advise generously
 
yahoo2

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Joined: 05/04/2011
Location: Australia
Posts: 1166
Posted: 09:53pm 25 Jun 2014
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for smaller gear a variable frequency drive (VFD) would be more appropriate.

someone like Automation Direct sell them.

A lot more flexible than a rotary convertor or generator. This guy explains it better than I can. VFD drives jeffs youtube
I'm confused, no wait... maybe I'm not...
 
Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9306
Posted: 10:21pm 25 Jun 2014
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=== POST DELETED ===

(realised OP was talking about using SD motor for 3-phase power, NOT generation per-se')Edited by Grogster 2014-06-27
Smoke makes things work. When the smoke gets out, it stops!
 
Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333
Posted: 03:15am 26 Jun 2014
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You do realize you can run a 3 phase motor off single phase using a capacitor.

But it will drop the motor power by about 1/3, in many cases this might not be a problem.

Pete.
Sometimes it just works
 
Rastus

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Joined: 29/10/2010
Location: Australia
Posts: 301
Posted: 04:42am 26 Jun 2014
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Hi Pete,
17yrs ago I rewired a 3 phase 5hp shaper to single phase. Yes it works, a mate of mine still has the machine, however the machine was under powered and it is necessary to slip the drive a number of times to get it working under load, otherwise it would just stall. To overcome that problem run caps were needed and the cost for them was more than a single phase 5hp motor. So the experience has left me lack lust on the results.

Hi Yahoo2,
I was hoping to here from you. I'm aware of other 3 phase options, however I'm being a cheap skate, trying to use what I have. You probably know that my mind hasn't been on this kind of project for a while, so rather than do a ton of research to start with for a dead end result, I thought I'd run it past the brains trust first. I'm not put of yet, but I'll be giving it a lot more thought until I'm convinced it's a waist of time plus Ill learn a lot along the way. Kind regards Rastus
see Rastus graduate advise generously
 
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