Cleaning Dynamo

[Dougie212]

Hi all

I’ve been following the service manual to clean the dynamo whilst it’s off my Minor. I’ve cleaned the Armature and Commutator poles with contact cleaner and very fine wet and dry and it’s looking really nice. There’s quite a lot of spot amongst the connection cables but, I don’t know if the risk of breaking something is worth trying to clean those…. I’ll see how brave I’m feeling this weekend.

The coils inside the yoke though are heavily sooted. I’ve not removed them from the yoke. Is there any safe method of cleaning the coils off or are they really at risk of disturbance if cleaned inside the yoke.

Thanks in advance!!

Duncan

[philthehill]

Just giving the dynamo parts a good blow off with compressed air is all that is required.

[geoberni]

If you really want to give it a good clean out, it's safe to use Isopropyl alcohol and then leave it to dry off.
Isopropyl alcohol is really flammable, so take the necessary fire precautions, but after you've used it, it will evaporate off in a few minutes.
It's an industry standard electrics/electronics cleaner, replacing a lot of the far more toxic stuff that used to be used last century (it still seems strange using that phrase, even though we're now almost 1/4 of the way through the current century )
You can get a Litre of 70% pure for around £7-£8
Because of shipping cost when buying it on line, it's far more cost effective to get 1ltr than 500ml.

[Dougie212]

Thank you both..

I feel as it’s off and I’m painting the yoke I should try and give it a bit of a clean.. the coils just seem so fragile I was a bit cautious about what to use. Last thing I wanted to do was break a wire…

[svenedin]

The field coils are wrapped in Egyptian cotton tape which you can buy and replace with care.

This has some info: https://www.dynamoregulatorconversions. ... inding.php

Stephen

[geoberni]

Thank you both..

I feel as it’s off and I’m painting the yoke I should try and give it a bit of a clean.. the coils just seem so fragile I was a bit cautious about what to use. Last thing I wanted to do was break a wire…

I would just stand it on end in a container, like a drip tray, old oven tin etc, and use a spray bottle to spray it down, a tooth brush could be used on the metalwork if required, but I wouldn't use that on the coils themselves, no point in risking physical damage.
Leave to stand and drain for a hour or so to ensure it's evaporated and you can reassemble.

I used to do this sort of thing for paid employment cleaning small electric motors back in the 70s , but with far more toxic liquids.
Whereas we've all been safely rubbing Isopropyl alcohol on our hands as sanitiser for the past few years...

[svenedin]

Thank you both..

I feel as it’s off and I’m painting the yoke I should try and give it a bit of a clean.. the coils just seem so fragile I was a bit cautious about what to use. Last thing I wanted to do was break a wire…

I would just stand it on end in a container, like a drip tray, old oven tin etc, and use a spray bottle to spray it down, a tooth brush could be used on the metalwork if required, but I wouldn't use that on the coils themselves, no point in risking physical damage.
Leave to stand and drain for a hour or so to ensure it's evaporated and you can reassemble.

I used to do this sort of thing for paid employment cleaning small electric motors back in the 70s , but with far more toxic liquids.
Whereas we've all been safely rubbing Isopropyl alcohol on our hands as sanitiser for the past few years...

Yes because removing the field coils is very difficult and special tools are required to replace them. There are a few companies that will fully rebuild dynamos to a very high standard. I have used Robson and Francis in Streatham, London. They have been going for many years and they first rebuilt my dynamo over 30 years ago and only did it again last year. Not bad going! Beat that alternator.

Stephen

[Dougie212]

Thank you all!! I’ve gone for the toothbrush option and given it a bit of a clean through. I think an air compressor is going to be popped on the Christmas list for jobs like this…

Thankyou as always!!

Duncan