De-ponging a motor

If it smells of ozone, replace the brushes. Otherwise take it apart and clean it.

Or it is a burnt varnish kind of smell, suggesting the motor has overheated at some point? I'm not sure how to get rid of that, as the varnish is indeed burnt. Maybe a wash in some organic solvent will remove the strongest smell, but now you need to remove the smell of the solvent...

Theo

Just two points here.

1. A serious pong may be from burnt windings - shellac - or it may be from a mains suppression cap having gone t*ts up and spilt its guts. Or it make be worn acrcing brushes. Open the machine up and identify which it is

1. Febreze is actually effective at all sorts of pong reduction.

But frankly, you can get these for less than £25 on ebay. Why not give it to someone else to fix and buy a brand new shiny one?

I've got two of these - one for coffee the other for spices. Both pretty old. I guess the brushes will wear out one day. Then I will buy a new one...

Or is it burnt coffee?

It’s the unmistakable smell of overheated windings, not ozone. The brushes are fine and the commutator is clean. I’m thinking that the only way of improving it will be a solvent wash. I was just wondering if anyone had done this before to a motor. I’ve ordered some isopropanol and will give it a go.

Tim

Nah. It’s that smell motors make not long before releasing the magic smoke… ;-)

Tim

Be careful. Shellac is what windings are covered in and *it dissolves in ethanol*. IPA *may* be OK. I just don't know.

Seconded. As a teenager, I worked in armature winding and the standard practise was to rewind any armature or stator where the wire's insulating coating had even started to burn. Washing out burned shellac isn't recommended for reasons given by the PP. It might be all that stands between the current state and a multiple short circuit.

At an extreme, adding a coat of varnish or shellac to the current winding might work. Of course, it'd be best to immerse the armature in a bath of shellac for an hour or two, but that would probably require equipment and materials not easily available in the required quantities. After drying, the commutator would also need to be cleaned and undercut.

Is a replacement armature available from the maker?

I don't recommend getting it rewound. A new machine'd probably be cheaper.

Is it not polyurethane or something these days? Seems unlikely to still be using beetle poop.

I'd not try washing it in MEK, which is supposedly a solvent for polyurethane.

Theo

After cleaning maybe you should give it a new coat of varnish (by dipping maybe?), that might seal the pong in.

Possibly, but that would mean buying varnish and faffing around. The bin beckons before I go to that much trouble. ;-)

Tim

Hmm, sounds like the experiment is worth doing for the”greater good” anyway. I really don’t care if it goes up in flames afterwards. ;-)

Tim

I would not bother with the iso, rather - I would liberally repaint the windings, with shellac, to try to seal the smell in. Hopefully, doing that, would not affect the armature Ballance too much.

Shellac varnish is called 'French polish' Shellac dissolved in ethanol

What sort of coffee do you wish to make? If you want espresso, that grinder wouldn't be up to the task - even if you can fix it.

You mean it grinds too fine?

Given that ethanol and propanol (IPA) are chemically very similar (give or take a couple of extra CH2 "links" in the chain) I would expect them to have similar effects on shellac.

I hadn't realised that. Presumably spilling gin, whisk(e)y, vodka or rum (all fairly strong ethanol solutions in water) would have a nasty effect if spilled on a French polished dining table...

I think there's a Yellow Pages advert about that ...

Oh no, that was a scratch...