The ebay generator restoration thread

[netherfield]

speedyman said:

Looks like just undo the black mounting plate, the motor windings will be attached underneath. You can probably replace the broken bolt with a new brass one. If it's an american motor then the bolt will be imperial size.

AEG is German, so likely metric threaded.

[rxe]

I’ve just been given (given!) this:



Other side:



Something heavy has fallen onto it and bashed the pulleys - you can’t get them any more, but generic taper locks will work fine. I’ll TIG up a new belt guard from ali sheet.

No fuel in it and the tank was clean. Oil was present. The carb jets were completely blocked, a bit of attention has got the motor running (badly, more carb work needed I think...).

The alternator spins freely once the damaged tin work was removed. No idea if the electrics work....

[Blue32]

Looks like an interesting project, shame about the smashed pulleys but i think both are the same size. Assuming I picked the right one, according to the parts list here: https://www.lingshondaparts.com/partscatalog/catal... the engine pulley is 119mm.

Good luck with getting it going

[rxe]

Ah, that's interesting - the parts book I found said 141 mm - but then I realised it was a US version, and they like their electricity at 60 Hz over there. Your 120 mm option will get the generator at 3000 rpm (50 Hz I think) with the engine at 3600 (peak power). Which is right for the UK!

Finding a pulley that works is harder than it looks - the combination of shaft diameter (25mm), keyway (7mm) and belt size (SPB) does not seem to exist off the shelf. Might have to get something modified....!

[dhutch]

Most sprockets/pulleys are largely kept on the shelf 'pilot bored' and can then be made to suit the required bore/keyway etc in what is a fairly routine operation. Even a lot of 'catalogue' items are actually held as pilot bored stock, or in the case of small pulleys even spun up from scratch bar stock as required.

Daniel

[rxe]

Yup, I’ve found blanks that can be machined to suit shaft and key way - but only in SPZ size so far, which is too weedy for 10 HP!

[dhutch]

rxe said:

...I’ve found blanks that can be machined to suit shaft and key way - but only in SPZ size so far....

That's not right, should be common as muck, from the likes of Brammer etc down to local machine shops.

My last company did loads of custom gearing options on chain driven kit and we used TransDev both for the majority of the stock sprockets as well as anything bespoke.
Might be cheaper alternatives if you can stand more faff, pulleys are a lot more simple than sprockets, but if you want a baseline they will knock you out what you want.

https://www.transdev.co.uk/pulleys/v-pulleys/

Daniel

[blueST]

Sorry to redirect this much loved thread for selfish reasons....

I have an old generic Chinese 3.1 KVA generator. The sort you see everywhere with all kinds of names on them. I last used it in the summer to run a 500w halogen lamp with no problems. Come to use it tonight and there seems to no electrical power coming from it. The voltmeter on the panel registers only a very tiny voltage. Maybe less than 24v

Anyone know what might be wrong?

[MXRod]

Start simple first , check brushes are moving freely in holders , they can stick with lack of use .
Then give the commutator a clean up with VERY fine emery paper or an emery board .
After that it will be necessary to dig deeper .

[dhutch]

I'm not expert, but stuck brushes seems a reasonable shout. Presumably once free they would clean up the commutator ok if left running with not load?

Presumably as you say old, and suggest inexpensive, it's not an inverter based unit.

[dhutch]

rxe said:

I’ve just been given (given!) this:



Something heavy has fallen onto it and bashed the pulleys - you can’t get them any more...

Have you managed to get sorted?

[blueST]

MXRod said:

Start simple first , check brushes are moving freely in holders , they can stick with lack of use .
Then give the commutator a clean up with VERY fine emery paper or an emery board .
After that it will be necessary to dig deeper .

Thanks, I shall start there.

[blueST]

dhutch said:

I'm not expert, but stuck brushes seems a reasonable shout. Presumably once free they would clean up the commutator ok if left running with not load?

Presumably as you say old, and suggest inexpensive, it's not an inverter based unit.

No, it's not an inverter. Just your basic generator.

[guindilias]

Few volts but measurable volts is more likely to need flashed with a 12v battery or similar than need the commutator ring cleaned or sticky brushes freed up - the generic ones have this happen more often than more expensive sets.

[dhutch]

guindilias said:

Few volts but measurable volts is more likely to need flashed with a 12v battery or similar than need the commutator ring cleaned or sticky brushes freed up - the generic ones have this happen more often than more expensive sets.

Can you describe the process?

[guindilias]

Basically your field (excitation) winding needs to produce voltage for your series winding to produce AC power. It normally does this through magnetism, the same principle by which a DC motor generates - but that residual magnetism can vanish in a genny that is old, or cheap, or both.
So you need to reestablish this by flashing it with a voltage source - such as a car battery or jump pack. As seen here - https://youtu.be/ECu4C__r1Qc

There is another way of doing it using a drill or grinder, spinning that backwards (by spinning the chuck/grinder disk) with the engine running and the outlet switched on, then taking your finger off the trigger and back on again which should result in a flashed genny which works perfectly.

I prefer the former due to my extreme self-injury skills and not wanting to be holding a grinding disc when it starts spinning under power during the second bit of the process but YMMV.

[guindilias]

Oh, and run it up to full load for a while afterwards - so say a 3kw heater or whatever - that way it will retain it's magnetism for next time better!

[rxe]

dhutch said:

Have you managed to get sorted?

Sort of!

I've got the engine sorted, starts on the key nicely and holds 3600 rpm. My god is it loud though.

I stuck the part numbers of the pulleys into ebay and turned up NOS items for not a lot of money. Amazing!

And then I've got distracted by summer jobs (Land Rovers and Lawns) so that is as far as it has got. Winter is here so progress will be made again.

[dhutch]

rxe said:

dhutch said:

Have you managed to get sorted?

Sort of!

I've got the engine sorted, starts on the key nicely and holds 3600 rpm. My god is it loud though.

I stuck the part numbers of the pulleys into ebay and turned up NOS items for not a lot of money. Amazing!

And then I've got distracted by summer jobs (Land Rovers and Lawns) so that is as far as it has got. Winter is here so progress will be made again.

Fair enough! Good old eBay!

[dhutch]

guindilias said:

Basically your field (excitation) winding needs to produce voltage for your series winding to produce AC power. It normally does this through magnetism, the same principle by which a DC motor generates - but that residual magnetism can vanish in a genny that is old, or cheap, or both.
So you need to reestablish this by flashing it with a voltage source - such as a car battery or jump pack. As seen here - https://youtu.be/ECu4C__r1Qc

There is another way of doing it using a drill or grinder, spinning that backwards (by spinning the chuck/grinder disk) with the engine running and the outlet switched on, then taking your finger off the trigger and back on again which should result in a flashed genny which works perfectly.

I prefer the former due to my extreme self-injury skills and not wanting to be holding a grinding disc when it starts spinning under power during the second bit of the process but YMMV.

Ah right, fair enough. Makes sense.

We have an old coach alternator on the narrowboat (24vdc) which has a field coil, alternator lamp, and it own 'ignition switch' as the engine doesn't have one. However you never have turn on said switch as it always self-excites itself. Which is sort of the complete opposite of what is happening here.

Daniel