Myford Motor problem

[Justin ThymeParticipant @justinthyme24678]

Myford Super 7

Only got a brief look at this tonight, the motor still works fine (a little wobbily)  but as you can see something is coming adrift and looks like it has been bodged up at sometime in the past.

I will be dismantling it sometime next week, but in the meantime, anyone know of this problem and what is needed to fix it

[Harry WilkesParticipant @harrywilkes58467]

Would think bearing ‘shot’ and the gunk is congealed grease, if thr shaft is not damaged you should get away with a bearing change if the motor is ‘shot’ then maybe think about fitting a VFD I did and been happy with result

H

[DiogenesParticipant @diogenes]

Is that muck epoxy / Araldite?

It’s a bit difficult to see, but it looks as if the rubber isolation bush has perished & collapsed.

If that’s the case I think (unless anyone knows otherwise) you’ll be lucky to get one off the shelf.

Someone might have a spare, or it might be possible to fabricate something ‘that will do’ to get it up and running again..

It’ll be easier to see once it’s out and cleaned up..

[Martin ConnellyParticipant @martinconnelly55370]

Unless there has been some other mechanical damage then, as Harry says, new bearings (and a good cleaning) should be enough. There is little to go wrong with 3 phase motors which is why they are so prevalent in industry. If you have a multi-meter then when it is removed from the machine a quick check of the phase resistances to check they are all similar would not hurt.

Martin

[Justin ThymeParticipant @justinthyme24678]

Motor is in good condition, runs smoothly and quiet. In fact, as unlikely as it looks you could use this now, it is not obvious using the machine,  the belt seems to support the weight of the motor.

The gunk seems to be a mix of epoxy, araldaite,  silicone and god knows what else.  I would guess this has been bodged up many times over many years,

I think the comment of “rubber isolation bush has perished & collapsed” is very likely the case.

I will be taken it to bits sometime next week, and trying to establish what is what.  I had hoped someone might of said, ‘yes common problem, you can get the spare here for 1.99″

 

 

 

[Clive Brown 1Participant @clivebrown1]

I agree that the problem seems to be collapse of the rubber support bush for the bearing. If the motor is run in that condition there’s a chance of contact between rotor and stator.

Years ago,I had a Myford single-phase motor with a similar problem. A rubber bush, moulded from Devcon Flexane, provided a satisfactory solution, but it’s not cheap to buy for a small job.

[Dave WoottonParticipant @davewootton]

Looks like the rubber bush for the motor resillient mounting has given up the ghost and been mercilessly bodged.This supports the whole motor by the outside of the bearing housings at each end, and provides some isolation from vibration, I’ve repaired ( bodged?) one of these on an ML7, whose original mountings had perished, with the same motor arrangement using a thin slice cut from the end of a car heater hose. I was fortunate to find one of almost the correct size at an old fashioned motor factors, had to buy a curved one as the wall thickness was greater then the straight lengths. A little tricky to adjust so that there is some isolation from vibration whilst restraining the motor itself from rotating in its mounting on start up. Lathe belongs to a friend who uses it quite often and the repair is still going after at least ten years. Couldn’t find a genuine replacement Crompton part at the time, so doubtful if they would be easily available now.

Good luck

Dave

Just remembered that in this motor the outside of the bearing housings at each end were hexagonal, I used a black car sealer called Sikaflex applied it to the hexagon and pushed the heater hose on, leaving it to cure before putting the motor back on its frame and tightening the clamps. Would think any filler or sealer would do just to fill the gaps, this was just what was handy at the time.

[Dave WoottonParticipant @davewootton]

I took another look at your picture and realised the motot mounting you have is slightly different to the one I repaired, that one did not have the steel ring around the rubber. But remembered I had a motor very similar to yours awaiting installation, so have taken a couple of pictures of the motor mount dismantled so you can see what it should be like.

Wouldn’t be so easy to repair using the method I outlined above, don’t think you would find a heater hose with a sufficient wall thickness to do away with the steel ring. As it’s a 3 phase motor and should run smoothly anyway,maybe you could do away with the resillient mounting and arrange something solid to replace the rubber, JB weld done a bit more neatly?. Depends on if you have access to another lathe to make the bits.

Hope this helps.

Dave

[Justin ThymeParticipant @justinthyme24678]

many thanks for all the replies, I will come back when I get it dismantled some time next week.

 

it could be very interesting having to make a specialist part that is no longer available – my sort of thing!

[Charles LamontParticipant @charleslamont71117]

A search on “resilient motor mounting rings” may help, but most of the ones I found at a quick look are hexagonal. As a last resort, requiring some work to make a mould, you could pour them in casting urethane. (I think silicone rubber would be too soft).

[noel shelleyParticipant @noelshelley55608]

Having run a Brook “Gryphon ” foot mounted single phase motor on an S7 for many years with no resilient mounting I would not be to worried if this 3 phase motor was run solid ! It appears, as several have said that the picture is of a bodged resilient mounting, my first thought was it had spat out the grease, though there seemed rather a lot, but the clue it was hard- araldite type was the give away ! Sikaflex or CT1 are both a flexable sealer/ adhesive type materials about £15 a cartridge – NOT a silicone ! Once opened IF the sealing cap is used this will keep for over a year – I always have a cartridge handy – it really does have a 101 uses ! It is much more solid than a silicone.

Since no one has come up with a supplier for a new part I take it that bearing in mind the age of these motors at 50+ years it is obsolete and NOT available ? Even as old stock, though being rubber age is what kills them ! Noel.

[Pete RimmerParticipant @peterimmer30576]

You could 3d print that rubber damper ring in TPU very easily.

[John HaineParticipant @johnhaine32865]

Brook 3 phase motor on my mill has a solid foot mounting and runs vibration free.  Don’t worry about it.

[John Haine]

On John Haine Said:

Brook 3 phase motor on my mill has a solid foot mounting and runs vibration free.  Don’t worry about it.

On John Haine Said:

Brook 3 phase motor on my mill has a solid foot mounting and runs vibration free.  Don’t worry about it.

+1 for it being a resilient mount (motor not bearing) bodged repair. Also +1 for moulding a new one from Sikaflex EBT.

[DiogenesParticipant @diogenes]

..once or twice I’ve used self-amalgamating tape to bodge build up resilient mounts, but it’s a bit of a trial and error process getting the tension of the layers right to supply the right amount of ‘give’..

Noel, do you know what ‘number’ a suitable Sika high modulus / heavy duty product might be? – like Loctite, there seem to be a million numbered variants all with slightly different properties..

3D printing might be a good shout…

[John HaineParticipant @johnhaine32865]

I suspect that the frame design is common between single and 3 phase motors which is why there’s a resilient mount.  The old single phase Brook motor on my S7 vibrated horribly but the new one, 3 phase TEC motor from NT, though it has such a mount runs sweetly without any vibration at all.

[Pete Rimmer]

On Pete Rimmer Said:

You could 3d print that rubber damper ring in TPU very easily.

Interesting – never heard of TPU but I have access to a 3d printer. how does it stand up to heat ? motors can get hot, wouldn’t trust PLA

On John Haine Said:

The old single phase Brook motor on my S7 vibrated horribly but the new one, 3 phase TEC motor from NT, though it has such a mount runs sweetly without any vibration at all.

Yes, this 3 phase motor is beautifully smooth, I could imagine it being OK with a solid mount

[Pete RimmerParticipant @peterimmer30576]

PLA prints at 220 deg C and TPU at 230. If your motor gets to 50 deg you’re in more trouble than a dodgy mounting.

[noel shelleyParticipant @noelshelley55608]

Cant Help with sikaflex data but try CT1 for data. Good luck. Noel.

[Justin ThymeParticipant @justinthyme24678]

Come up with a repair and it seems to have worked well.  I 3d printed a bit to fit round the 9 sided polygon, then I used 1mm pond rubber to achieve the correct diameter.

I used pet-g filant for the 3d print, that stays fairly hard to at least 100°c   and wont melt till over 200.   and even if it gets a bit soft it is enclosed on all sides.

The rubber bit seems to be OK, with the motor tightened up I can still get mayb half a degree of flex. and on running it, it sounds right.

[DiogenesParticipant @diogenes]

👍

[john fletcher 1Participant @johnfletcher1]

Several years ago I had a similar motor problem. No success via Brooks, so I went to a local motor factors and had a look through their range of exhaust rubbery type mounts and found what I needed or near enough, its still going strong. John

[noel shelleyParticipant @noelshelley55608]

Good to hear of a satisfactory outcome ! Noel.

[Dave WoottonParticipant @davewootton]

Very nice repair Justin, Speaking as a dinosaur it’s great to see these techniques in practical use. Also good to see some feedback and closure on a posted question. I often wonder what the outcome is of some of the questions raised.

Dave

[Justin ThymeParticipant @justinthyme24678]

and if anyone comes across this thread whilst trying to find a mount for this motor/machine, I would quite happily make you one (for a small donation to the mens shed)

just send me a Private Message, and I think that would appear in my email account, so there would be more chance of me seeing it (I sometimes only look at this email account once a fortnight, so don’t expect a quick reply)

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