I have the opportunity of a Harrison M250 (600) flatbed lathe very cheap - it's 3 phase unfortunately. Anyone know how easy/expensive it is to convert to single phase?

Thanks and Merry Christmas to all Locosters
Ian

Either buy an inverter or go to machine mart and buy a single phase motor. Just be aware (if i've got the stuff i've read correctly) 3 phase motors are normally half the speed of single phase, therefore you need to get a single phase motor with double the windings or something aka check the speed of the single phase motor.

not sure how big the lathe is but you can get an inverter but prob expensive
my harrison which is v old and quite small has a single phase motor on it running via a vee belt and works perfectly
Ray

I have a Harrison lathe that had a 400v 3 phase motor.

Went to Machine Mart and bought a 250v motor for it. Works fine now.

The M250 had a choice of 2 motors
900W (1.25hp) on the 40-1500rpm model (pre 1998)
1300W (1.75 hp) on the 52-2000rpm model (post1998).
Probably a 4 pole model(1500rpm). Shouldn't be hard for an electrical bod to re-wire for you if you do the fitting of a single phase motor, or to fit an inverter if that the way you go.

A single to 3 phase inverter, 1500w is about 200+vat

Be aware that it weighs 365kg for the short bed version, 450kg for the long bed.
Regards
Hugh

I have a Harrison M300 and used a Siemens Micromaster 440 frequency converter. I bought it second hand on the internet and the previous owner even programmed it to my needs (although it is not so difficult).
You can connect all switched directly to the frequency converter and the nice thing is that you can select any speed you want.
I think the problem with single fase motors is that you can't reverse the motor. You will need this if you are going to cut threads.

http://myworld.ebay.co.uk/drives_direct_nottingham/

If you change the 3-phase motor for a 1-phase one of the same physical case size then you should be aware that the new one won't give you as much power (a fair amount of the space inside the 1-phase motor's housing is the starter winding). They also can't be switched on quite as frequently (i.e. on and off several times a minute) as the starter winding may overheat. You will also have to play with the lathe's switchgear if you change to 1-phase.

Using a 3-phase converter is also a compromise, as they have their own problems - you can't have the coolant pump running on its own as it won't be big enough to play its part in the process of creating 3 phases, but you can start the main motor THEN start the coolant pump. There are ways around this though, e.g. running a 3-phase pilot motor makes the supply to the lathe almost identical to 'proper' 3-phase (a pilot motor is a 3-phase motor that runs permanently while the converter is on, which helps the converter to work properly).

But for home use this doesn't matter in the slightest. I don't drive my 3-phase Colchester Student anywhere near as hard as a machine shop would, so these limitations are irrelevant - but it's worth noting in case you have problems). My converter is from Transwave - well worth a look at their website, and they have always been ready to help out a user. It was them who gave me the wiring diagram for a pilot motor!

HTH (and I hope it doesn't confuse you...)

P.S. The Harrison is a nice lathe!

i have got a converted harrison. it used to be 3phase, i pulled the old 1.5hp 3phase motor off and fitted a new 4 pole 1475rpm 3hp single phase motor.

took about an hour to do the swap, just make sure the new motor has the same size shaft, the motor foot patten is not too important on the harrison as the mounts are adjustable.

I have my Myford super seven converted to three phase so we can control the speed and direction.

With the controller we can tap and reverse the machine.
On the Myford single phase lathe I had this always had to be done winding it by hand

The other advantage is when you pair off you can change the speed as you go.

How about a BEL = bike engined lathe. Old fireblade engines are cheap and will give you plenty of revs. Stick a house rad on instead of the bike one and heat the garage at the same time.

how much does it cost to get 3 phase power installed?

I was quoted several thousand Pounds... most modern housing estates have 3-phase running along under the pavement outside - they take one phase off for each house, thus balancing the load. Unfortunately I live in a cul-de-sac, so the 3-phase petered out before it got to my house - I'm at the end of the cable, so only 1 phase available... They would have had to cut a trench across the road to get to the place where 3 phases were available.

If I had the 3 phases outside my house I would have had to run the cable up to the end of my drive so they could make a hole and connect it up, and I would also have had to provise the proper termination (meter, fuse box and the like) totally separate from the usual household supply.

Oh - I would also have had to convince the electricity company that I had a legitimate reason for having 3 phase...

In the older part of my village the houses are supplied via overhead lines, and all I would have had to pay for was 2 more wires to the house and the termination equipment...

Thanks for all the replies and detailed info. guys this is really helpful and means I'll definitely get the lathe, hopefully in the spring when the workshop is decommissioned.

There is likely to be some other stuff too such as metal benches, vices etc so I'll post them up when available to see if anyone is interested, they should be reasonably cheap.

Cheers
Ian

quote:

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Originally posted by RedAvon
There is likely to be some other stuff too such as metal benches, vices etc so I'll post them up when available to see if anyone is interested, they should be reasonably cheap.

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I've just bought a Harrison M250 this week. It's 3 phase and I'm going to get an inverter to run it off my domestic supply. I'll let you know how I get on

Dave