Three Phase Converters

I need to run a 7.5HP three phase lathe off a single phase supply.
Has anyone brought/used a phase convertor in that power range, if so where
did you get it from, what do you think of it?
Is it a static or rotary?
Any comments
Thanks
Stephen.
Reply to
Stephen Woolhead
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I haven't got a convertor that large but I run my lathe (Colchester Student), mill (Bridgeport clone) and bench grinder off a Transwave 5hp static unit. Without going and checking labels I expect the lathe and mill are only a couple of hp each. I can also run them both together just fine although I can't turn on the lathe if the mill is in mid cut as the mill motor stalls. I can put the lathe on first and leave it idling and then switch the mill on though. Once the mill is going I can then use the lathe. Not sure why it happens that way round but it's rare I want to use them both together anyway.
I've had it 10 years now and no problems at all. If I want the lathe on a high speed I do have to turn the control knob on the convertor up a notch from position 3 out of 6 to position 4 but the mill doesn't seem to care what speed it's on as far as power supply goes.
I'd suggest a 10hp convertor based on my experience so you have a bit of spare supply. Go too high though compared to the motor you want to run and it won't work. I get nasty humming noises if I try to run the bench grinder on its own so I switch either the lathe or mill on first to balance the supply before doing any grinding.
Dave Baker - Puma Race Engines
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I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.
Reply to
Dave Baker
Looking at the Transwave site my question is answered. The Student has a 3hp motor and with a static converter in multi machine use it says you have to switch the largest motor on first and off last or the smaller motor will stall.
I'm guessing the lathe and mill together are close to the limits of my 5hp converter then but it handles them both just fine. Given the extra cost of a rotary converter I'd hope the static type would do what you need.
Dave Baker - Puma Race Engines
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I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.
Reply to
Dave Baker
I run a 10 HP static converter from Boost Electrical.
I use a 7.5 HP pilot motor, and the converter provides power to a drill, a mill and a lath ( 7.5 HP )
The unit does not provide a " neutral " for 240 V controls, suds pumps, DRO...
I have fitted extra capacitors on the lath, so I don't need to change the power setting on the converter when I use it.
I have a 240 V supply I use to get round the lack of 240 V from the converter, I had to figure out how to do this for myself.
Although installation was not easy, the unit has given me little trouble in the two years I have been using it.
Boost 's websight is
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-- Jonathan
Barnes's theorem; for every foolproof device there is a fool greater than the proof.
To reply remove AT
Reply to
Jonathan Barnes
Stop putting it off and buy one ;)
Chris
Reply to
Chris Eilbeck
LOL!
Stephen.
Reply to
Stephen Woolhead
I used a 4hp unit from motorrun phase converts near isleworth for ten years with a polisher very reliable unit. the polisher was frequently used for 10-12 hour periods and the motor ran hot, I won't describe how we kept it cool;-). The current was probably balanced at each one of the settings, .5, 1, 2 or 4 hp. I did add an idler motor and use the thing to power several pieces of kit, it was miles better but i never ran it like this for an extended period of time...
Then I built a convertor, I am well impressed. I have half a dozen bit's of kit wired to it and it runs perfectly. I just turn it on and forget about it, it's like being wired to the mains.. It runs quite well balanced, it stays within +-4% during running in fact most of the time it's much better than that..
they are very simple and there are loads of details on the internet..
-- richard
Reply to
richard

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