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  • 1 year later...

Hi,

So, I finally got around to servicing my Brenray cleaning machine today as I have time to start servicing again. 

I decided to rewire it as I didn't trust the wiring on there for safety so attempted to take the motor apart and broke it within 30 seconds ... Clever me!

At the top of the motor (inside) were two graphite looking blocks that sat pushing against the top of the motor. Not sure what they are or do but they are no longer attatched and are in pieces. I also found the bearings on the motor are press fit to the spindle and I can't get the gubbings of the motor out as the top of the spindle has been mushroomed over by the last owner.

I've no idea what to do. So I've come here for some common sense help please.

I either need to repair it, replace it or tell me it's pointless and to go try and find an Elma RM90 or super elite, if you have one for sale let me know please. I would happily purchase it! (For the right price!)

Many thanks in anticipation of your responses,

Alex

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I salute your gallant attempt. :thumbsu:

I think your best bet is to take the motor to a motor repair or appliance repair shop to get it fixed. The two carbon brushes should have be removed first before taking the motor cover off. The 2 black bakelite knobs on the sides have screwed on covers. Unscrewing it will release the spring which pushes the carbon brushes against the motor commutator.

It should be a simple fix for someone with the right knowledge. 

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Try looking for a company that does alternator rewinds or a competent Auto. Electrician in your local area.

They might be able to help you with advice or sugest an alternative small electric motor that could be used without breaking the bank.

I've had a few alternators and starter motors for old motorcycles refurbished with brushes replaced locally over the years for a reasonable cost.

Sent from my moto g(6) play using Tapatalk

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Brushes wear out  anyway and are renewable and should be available at material houses, commutator contact surface if rough  can be turned on a lathe, you should also check the shaft and bearings/bushings for wear and turn if neccessary and grease ( heat resistant grease) 

The coil also is to be checked electrically.

I would check above mentioned parts for wear, if alright just clean grease and instal new brushes, if worn and you have no access to a lathe, you got to let someone who dose ,fix it.

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@Nucejoe @nad @HectorLooi @CaptCalvin

Many thanks for all your responses. So, I've spent a while getting this baby apart.

I've been in contact with a local repairer and he said to just by new bushes and fit them. easy peasy.

However, I wonder if you guys would mind commenting on the internals of this motor to see if it's still good? I know nothing about motors or rotors unless they're in a watch!

If you think i can straighten the plates up. Maybe polish the steel bits with a wire brush (I have small brass brushes)? Not sure what else could be done? But that it looks sound otherwise. Then I will order some new bearings for it to be on the safe side and some new bushes.

As can be seen I can't actually rewire this thing as I had hoped but I will add some additional sheathing to it as the old stuff had disintergrated.

Cheers,

Alex

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The shaft and commutator look Okay and if no short circuiting in coils, it should run.

If you have access to compressed air, I blow air to the inside to clean it some. 

Some folks put a drop of oil on the commutator where it comes in contact with brushes.

 

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1 hour ago, Nucejoe said:

Some folks put a drop of oil on the commutator where it comes in contact with brushes.

 

47 minutes ago, HectorLooi said:

WHOA! No oil on the commutator!

Oil would mix with the carbon dust as the brushes wear down and form a sludge which would short out the commutator eventually. 

Agreed. Don't put oil on the commutator, but if you are trying to repair the thing, then clean off the old graphite dust.


The graphite will act as a lubricant as the brushes wear, so no other lubricant is needed, however it is also conductive, but generally burns away as the motor runs. If you add oil, it will build up more rapidly and may not burn off.

The result can be spectacular, as the commutator and/or the coils exit stage left, so clean out the old graphite dust as much as possible before replacing the brushes. I eventually had to replace the motor in my last washing machine (after 15 years of changing the brushes regularly and cleaning out the old dust), when it exploded with a very loud bang. The commutator had finally worn through and shorted, taking out the spring on one of the brushes, one of the field coils, and the fuse in the fuse box. Smelly, noisy and somewhat alarming, the more so as this was a relatively large motor.

Use a stiff (nylon) toothbrush for the commutator, not a brass or steel wire brush, as the commutator may not respond well to abrasion (and metal wire bristle can break off and stick between the commutator pads and short things out).  Don't use sand paper unless the commutator is really bad, as this will shorten its life.

You can generally lubricate the bearings, assuming they are not sealed.

If the motor is beyond repair, then you can substitute something more modern, so long as the shaft is the same diameter, or can be adapted, and the power rating and RPMs are similar. In my experience of fixing old electrical tools, this is not an exact science, so close enough is probably good enough. If you do decide to replace it, you might also add a modern triac speed controller, to let you pick a suitable speed from whatever motor you substitute.

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2 hours ago, alexjt said:

If you think i can straighten the plates up. Maybe polish the steel bits with a wire brush (I have small brass brushes)? Not sure what else could be done? But that it looks sound otherwise. Then I will order some new bearings for it to be on the safe side and some new bushes.

As can be seen I can't actually rewire this thing as I had hoped but I will add some additional sheathing to it as the old stuff had disintergrated.

The plates are soft iron, and you can probably push them back together with your thumbs (or with a few gentle taps with a nylon hammer or similar).


Good luck finding the correct bearings. You may be in luck, but unless they are particularly bad, then other than a good clean and a little machine oil in them, I think I might leave well alone.


The brushes are probably much easier to find. If you can't get an exact match you could cut larger ones to size. Graphite can be cut with a junior hacksaw, and filed and sanded to shape but it is brittle and easy to fracture if you are a little heavy handed, so don't try jamming it in the vice without some sort of soft jaws, or you will just end up with a pile of broken pencil lead.

Getting the curve of the brush where it runs against the commutator right can be done by clamping the lump of graphite between a couple of bits of wood, and running a wood drill next to the edge in the drill press to get a rough profile. Use a drill bit the same diameter as the commutator. You can also do this by gluing some sand paper to a dowel of the correct diameter and putting that in the drill press. This slower but less likely to grab the brush and break it.

Running the brush in the motor will bed in the correct profile, once you have it almost correct.

Heat shrink tubing would probably be a good idea on those parts where the old sheathing is looking dodgy.

Edited by AndyHull
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1 hour ago, HectorLooi said:

WHOA! No oil on the commutator!

Oil would mix with the carbon dust as the brushes wear down and form a sludge which would short out the commutator eventually. 

Oh goodness,  thanks for the advice.

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I have limited knowledge on the subject but I have rebuilt a cleaning machine which turned out working okay without having to replace anything besides the wiring but I can't be sure I did any of it right so take my 2 cents for what they're worth. There should be four cables that connect to the motor. Here is what I did, I connected the 2 that came from the potentiometer to the brushes because that will control the voltage supplied to the rotor and allow me to control the spin rate through the knob. The other 2 cables would have fixed voltage which I connected to the stator (the unit of stack of iron plates surrounding the rotor).

Here's where I hope more knowledgeable people can chime in. Everything works but not flawlessly. When I set it to a certain speed, I can see/hear the motor occasionally speeding up/slowing down on it's accord without the knob being touched. Should it be doing that? What could be the problem? Was my cabling wrong? What would happen if I connected the potentiometer cables to the stator instead?

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@AndyHull

Cheers for the info Andy. So I'm in contact with a company to make some for me. Not sure how much they will charge to do one offs. My main problem is getting a spring and the shape. So as much as I want to get a DIY solution, I might just pay someone to make me some. 

If all this doesn't work, I've no idea on the RPM of the machine. I know it says its 200V on the other Brenray motors with plaques. There is a variable speed knob on the machine so I could vary it to what I want. The shaft is less of a worry as I'm adapting it to fit Elma cleaning baskets so an 8.00 mm shaft would be ideal. However, I've no idea where to buy something like that and the quick google search I did returned little. Maybe you know a good site I could checkout?

Cheers!

Thank you everyone else who keeps commenting and helping out too!

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I posted a few days ago about the motor of my Brenray and now I want some help with the heating element.

Currently its hanging on by a single wire. Which isn't what I want so would like to replace it.

I've seen the elma heating element available from walshes, but could someone identify what mine is so I can get a direct replacement.

Many thanks,

Alex

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  • 1 month later...
  • 2 months later...
  • 1 year later...

Hi

Just bought this watch cleaning machine.(mainly cos it was cheap) Its a brenray with all the bits and pieces. It all works. it spins,heats etc but that is all i know about it. I plan to strip and rebuild it in a few weeks time.(must have a play with it first).

So any one with any info diagrams manuals or can give me any tips or help in any kind of way please let me know.

cheers

gary

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  • jdm pinned this topic

Hey 

I am attempting to rewire a brenray cleaner exactly the same model as below in pic.

I have done my due diligence and looked around the internet for help and low and behold we have one on our own forum.

The problem i am having concerns the power lead,

Both the one from the motor and the one leaving for the plug seem not to have all the wires.

In one lead you have a blue wire and a earth and in the other lead there seems only to be the blue wire.

This is surely not correct??

Or is this correct or can i not see in the picture were the other wires go????

cheers

gary

 

 

 

 

 

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