Three phase motor drive

A young man here has acquired a Harrison Lathe which was desdined by a school in North Uist to the skip.
I have not yet seen the lathe and hope to do so when the gales stop but I
thought I would throw in a question here in the meantime.
Should he convert to single phase?. I can give him a suitable motor. or would he be better to go for some sort of converter and keep the existing motor.
Given that he is currently working in North Sea maintainence I don't think that cost is a priority.
A few thoughts on the best way to proceed would be appreciated.
I realise that you wish to know the type and model of the lathe and I hope to find that out tomorrow when he calls and takes me down to see it. He thinks I am too old to manage on my own.
Donald South Uist
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If the lathe has a three phase motor then absolutely, get an inverter. An inverter will cost the same or less than a suitable single phase motor and once you/he have had variable speed on a lathe, you/he will be loath to go back.
My 2d worth.
Mark Rand RTFM
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On Sun, 14 Jan 2007 19:00:39 +0000, Mark Rand

I definitely socond that. Variable speed is well worth getting. Have to check that the motor can be wired for 240V 3-phase though as VFDs that run off single phase will generate 240 3-phase.
Regards, Tony
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On Sun, 14 Jan 2007 19:00:39 +0000, Mark Rand

Donald, I will also go with what Mark says with a couple of points.
The main one being that the motor must be able to be configured to work on 220 volts in delta to make use of an invertor. Some early 3~ motors are hard wired in Star with just three cables exiting the connector box. You need 6 wires or cable connections to enable this conversion to run.
As in.
http://homepage.ntlworld.com/stevenson.engineers/lsteve/hidden/invertor%20motor.JPG
Second point the invertor will take the place of all the old starter and overloads and so make a more up to date and reliable setup.
-- Regards,
John Stevenson Nottingham, England.
Visit the new Model Engineering adverts page at:- http://www.homeworkshop.org.uk /
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John Stevenson wrote:

http://homepage.ntlworld.com/stevenson.engineers/lsteve/hidden/invertor%20motor.JPG
I agree with an invertor, I have one on my Harrison L5 and its wonderful. the motor change on an L5 if nesesscary to get a 240V 3 phase is very simple, so even if the current motor is 415V only (mine was) a new motor and invertor is simple and not overly expensive
Dave
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I worked in a machine shop for 45 years (Well we did work sometimes) and never had the use of a converter and it was the same at home until I was offered one very cheap. After seeing one on my mates lathe I could not get one fast enough. I only had the chance of the one so it is wired on five pin plugs so I can use it for the Myford and Mill/Drill when I can get hold of another two plugs the Hobbymat and the drill will be going the same way. Not sure about the shaper. I am converted to the converter.


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No gales yesterday so I have been and had a look at the Lathe.
It is an L5, or maybe an L5A, I didn't measure the centre height but think it is the latter. From the hand book it would appear that the lathe was made before 1959. Condition, fair to good, just in need of a good clean, a few adjustments, and lubrication. (Sounds like a description of my own condition)
The motor is a 1HP 3Phase Brook but it is the wrong type, having only 3 wire connection. What he needs to know is the type and model of motor and invertor he should get and where can he get it from. I know nothing about such things so any advice from the group would be appreciated.
One essential item missing from the lathe is a tool post. We can of course make one but if anyone has one or knows where to get one of the right type, please let us know.
Donald. Isle of South Uist.
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wrote:

To be honest if he has to re-motor this I'd go up to a 2HP or 1.5Kw motors as these Harrison's can put some drag on a drive train when cold.
Any 3 phase 6 wire motor at 1425 revs [ 4 pole ] will do, I have them here but shipping would be a killer.
Best bet for an invertor is the Altivar 11 range from RS Components, I think the 1.5Kw model is 150 which is very good value.
go to rswww.com [ yes weird but it's right ] and type in 431-9190 -- Regards,
John Stevenson Nottingham, England.
Visit the new Model Engineering adverts page at:- http://www.homeworkshop.org.uk /
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wrote:

I've got a 4-way post off a Colchester Student which might help you. I'll check dimensions later if you're interested.
Cheers Tim
Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service
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Donald wrote:

A Quickchange toolpost from ARC Euro trade fits nicely ( http://www.arceurotrade.co.uk ), I have the the '200' model and it works well. I needed an M12x160 bolt to attach it to my topslide, as the exisiting bolt was to short. I have an L5 btw, but I think it should fit an L5A ok, there is quite a lot of adjustment for the center height available. Whilst not the cheapest option I have a Newton Tesla drive on mine, it is a simple swap, as the inverter and motor come ready setup and 'just' bolt on, with a control box etc. Makes a neat job, but you could do it for less if you are inclined, and it could be just as neat once you put the effort in. I was looking at the inverters John S mentioned to do the same job. mine is 750W (1hp near as makes no odds) and I havent had any probelms with it yet.
hth
Dave
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On or around Sun, 14 Jan 2007 19:00:39 +0000, Mark Rand

having studied this recently, you'll be lucky to get a good inverter/VFD for the price of a single phase motor.
however, if money is not a major consideration, then the inverter is still the way to go.
--
Austin Shackles. www.ddol-las.net my opinions are just that
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