Motor for ML7

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Motor for ML7

This topic has 11 replies, 7 voices, and was last updated 6 May 2021 at 15:13 by ken king, King Design.

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1 May 2021 at 17:13 #542565
ken king, King Design
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@kenkingkingdesign
Help ! The Metro-Vickers motor, type BS 2408, 1/3 hp, 1425 rpm, of my old ML7 has just gone phut. Initially it developed a dead spot and would not start unless rotated a 1/4 turn or so. Now it just buzzes at me or creeps round at extremely slow speed.

Any suggestions for sourcing a reasonably priced replacement will be hugely appreciated, or if you have a suitable motor spare please let me know so we can discuss price etc.

Thanks,

Ken
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1 May 2021 at 17:13 #20267
ken king, King Design
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@kenkingkingdesign
replacement needed
1 May 2021 at 18:13 #542582
Andrew Tinsley
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@andrewtinsley63637
I assume it is single phase? It sounds as if the capacitor is faulty, if it is a capacitor start motor. Worth checking as a capacitor will be under £5, rather cheaper than a new motor.

Andrew
1 May 2021 at 18:24 #542585
Grindstone Cowboy
Participant
@grindstonecowboy
I have a ML7 that has had a Machine Mart motor fitted. I'll just go and see what model, it still has the sticker on it. Guard had been modified to fit it though (but not a major job and it still covers the rotating bits unless you go and stick your hand somewhere silly) and extra holes were drilled in the mounting plate, although I think it could have been made to fit the existing holes if whoever did it had tried a bit harder

Rob
1 May 2021 at 18:40 #542587
Mike Poole
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@mikepoole82104
If the motor has failed and replacement caps and the centrifugal switch if fitted do not respond to TLC and replacement then it may be time to consider whether a VFD would be a good route to go down. If a replacement motor to give the same manual speed change facility is all that is required then motors are available, direct replacement motors with an imperial shaft tend to be a bit dear but a 3 phase motor and inverter package will cost more but the usability improvement is almost universally recommended.

Mike
1 May 2021 at 18:55 #542590
Grindstone Cowboy
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@grindstonecowboy
Well that was reminiscent of another thread – having taken the motor off the lathe a couple of months ago so I could strip and repaint the lathe, it took me twenty minutes to find it again! Anyway, here are some photos of the modified guard and the Clarke motor.

Looking at the price, not sure how long ago that motor was fitted!

Rob
1 May 2021 at 19:02 #542592
duncan webster 1
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@duncanwebster1
I ran an ml7 for many years with a 1/4 hp motor. It's not a lathe for big cuts, but it would happily take 40 thou deep
2 May 2021 at 23:57 #542815
ken king, King Design
Participant
@kenkingkingdesign
Rob, thanks for going to so much trouble. It's a single phase non-capacitor motor, and as I had nothing to lose I took one end off and cleaned up the centrifugal switch contacts and ring, (thanks for the tip Mike) and blew all the swarf out, at which point didn't my wee compressor give up the ghost with a dribble of smoke ? Gremlins are swarming, so look out !

Reassembly is under way, sufficiently advanced to say the motor runs again, but not yet fully integrated into lathe so unsure about revs being achieved, but looking much better, thanks to all.
5 May 2021 at 09:46 #543245
ken king, King Design
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@kenkingkingdesign
Hmm … situation unchanged apparently. There is still a dead spot requiring some hand rotation to get going, but for the moment I can use the lathe on that basis to clear a job. Do the symptoms suggest a dead field winding perhaps (my understanding is sketchy) and if so is it practical to consider repair rather than replacement ?
5 May 2021 at 09:59 #543250
John Haine
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@johnhaine32865
Metrovicks became part of AEI sometime in the 1950s though I think the brand was still used on heavy machinery for some years. My father was a graduate apprentice at MV in the 30s and worked there in early wartime! Your motor will be 50 years old or more.

I think the motor deserves a leisurely retirement and its role being taken over by something to a more modern spec. As it happens I have a cap start induction motor from a VMB (to which I fitted a 3-phase motor) gathering dust. It has a 3/4 shaft if that would fit your pulleys? Let me know if interesting.
5 May 2021 at 11:46 #543272
Trevor Drabble 1
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@trevordrabble1
Ken , I also have a Brooke motor available , complete with a new quality start/stop/reverse switch , which was removed from my recon S7 shortly after l bought it from Myford Nottingham in order to fit a Newton Tesla VFD assembly . If you're interested , can email you pics . Trevor .
6 May 2021 at 15:13 #543530
ken king, King Design
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@kenkingkingdesign
What helpful chaps you all are, thank you. Trevor, I've sent you a message,

Regards,

Ken
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