WM250 inverter conversion.

[Mark P.Participant @markp]

Hello all, I am doing an inverter conversion and can’t decide the best way to mount the new motor (80 frame).
I have removed the origional control box, but can’t come up with a tidy mount for it. How has everyone done theirs? I realise I will have to drill and tap the lathe casting, should I fit the motor on a pivot for belt tensioning or solid mount it and use an idler arrangement for tensioning. Any hints/ideas welcome.

Regards Mark P.

[Mark P.Participant @markp]

Motor mounting.

[Brian OldfordParticipant @brianoldford70365]

Were it my job I would go with the "motor on a pivot". If you go for an idler you will either reduce the belt "wrap-around" or need to bend the belt in the reverse direction. Although OK for poly-vee belts the later isn't really recommended for regular V-belts. If you follow the pivoted motor scheme try not to simply rely on the weight of the motor to tension the belt. Include some sort of positive tensioning arrangement. Take a look at the arrangement on traditional British machines of comparable size.

[Rik ShawParticipant @rikshaw]

Mark – I'd like to hear how you progress with the conversion and maybe some pics on completion? The sooner my WM250 has been electrically castrated and refitted the happier I will be.

Rik

[John RuddParticipant @johnrudd16576]

Isnt the orig motor a flange face mount rather than foot? Couldnt the new motor be flange mounted, then idler for tension?

My SPG LATHE, albeit bigger came with a pivoted mount with its motor mounted on an L shaped bracket……This arrangement really lent itself to a foot mount motor, I ditched the L bracket, the pivot mount was already drilled for an 80 frame motor ……lucky I guess…

[Mark P.Participant @markp]

Thanks for the replies. I have fabricated a pivoted bracket for the motor, I am going to fit a threaded adjuster for belt tensioning. Just waiting for my pullies and taper lock bushes to arrive.
Regards Mark P.

[Niels AbildgaardParticipant @nielsabildgaard33719]

http://i.imgur.com/9lKJ5am.jpg

Wise choice

PowerTwist belt from Fenner

Edited By Niels Abildgaard on 26/04/2017 17:15:26

[john kennedy 1Participant @johnkennedy1]

I converted mine a while back and have some photos in my albums.

A bit of a lash up I know but it works well.

The new motor is obviously a lot heavier and I was concerned about the weight causing a twist ? So slung it underneath.

I would be very interested in seeing a different way of doing it.

[Mark P.Participant @markp]

Well I’ve finally fitted the inverter/motor to my WM250, wish I’d done it earlier it has transformed the lathe. It seems much smoother in operation, parting off is now a pleasure or could it be me? Only thing is I could do with is a speed readout I can’t get the original one to work but only a minor niggle.😊

[John RuddParticipant @johnrudd16576]

Mark,

What is the issue with the tacho not working?

[Neil WyattModerator @neilwyatt]

Posted by Mark P. on 06/06/2017 17:21:16:
Well I've finally fitted the inverter/motor to my WM250, wish I'd done it earlier it has transformed the lathe. It seems much smoother in operation, parting off is now a pleasure or could it be me? Only thing is I could do with is a speed readout I can't get the original one to work but only a minor niggle.😊

You can probably get the tacho to show RPM, you just need to program in the gearing. Of course it will only be 'right' for one gear ratio, say full gear not back gear.

Neil

[Mark P.Participant @markp]

Hi John, not sure about the tacho but the power/filter unit had died, I disconected the wires from it and gave the tacho unit 3 volts I tried combinations of connections to the “read unit” didn’t get a convincing speed readout, should the read unit need it’s own power supply. I assume the whole lot should run off 3 volts.
Neil,I can’t see the inverter when stood infront of the lathe.
Mark P.

[John RuddParticipant @johnrudd16576]

Mark,

The filter psu board provides 5volts to the display unit… There is another thread ( cant put my finger on it now….) but the guy converting his machine had the same issue. There are photos of the board and the connection details in that thread and info on how we got it working….

[Mark P.Participant @markp]

John,
Would that be Dustys thread? I assumed that the display would run off 3 volts, I can get it to give me a reading but not what it should be.

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