Uneven Alternator Brush Wear.

Any ideas why my alternator regulators only wear down one brush?
It this normal or a slip ring issue?







Alternator works hard for it's keep usually producing 30A when running. It's a Bosch 55A.
Pictured is 6 month's wear...new brush o clock.

shamwari

Is the commutator worn unevenly, or badly pitted or scored? if you spin the shaft by hand, does it rotate correctly or eccentrically?

hmm....thanks you have me thinking check the bearings. It's fitted to a van so, minimal space, usually I have to take nose off and radiator out to get to it...unless I'm missing an easier way to get the belt off. I'll have an investigate later, maybe I have a suitable donor car alternator.
There's a belt noise when engine's warming up not sure if you'd call it a chirp or a squeal.

So that sort of wear is unusual then? Nothing to do with current load or RPM?

Greyfoot

belt noise can be due to shot pulley as well

Bearings are ok but not brilliant. The offending slip ring is heavily pitted and shrapnelising and much further worn than it's partner. I was thinking of replacing the slip rings until I took my donor apart and I've no idea how to separate them from the commutator so I think I'll be cutting my losses and re-installing it after sanding the existing slip ring smooth. Hopefully this belt goes back on the way it came off.

shamwari

Belt noise on startup can be caused by the electrical load on the alternator. I once had and old diesel estate that chirped like a pet shop on cold start. It lasted for about 15 secs and stopped - it coincided with the glow plugs switching off

Slip ring replacement (for Valeo units) shown here

http://youtu.be/f56-26I6idc


As for reinstalling your belt, what make / engine is your van?

shamwari

shamwari wrote: »

Belt noise on startup can be caused by the electrical load on the alternator. I once had and old diesel estate that chirped like a pet shop on cold start. It lasted for about 15 secs and stopped - it coincided with the glow plugs switching off

Yeah same deal I reckon, except my glow plugs are off before I crank. Mine runs a weak starter battery, 250Ah auxiliary batteries and sometimes a fridge and a laptop + auto-electrics.

shamwari wrote: »

Slip ring replacement (for Valeo units) shown here


http://youtu.be/f56-26I6idc

Thanks I had a look at a few last night I reckon it's doable if I get a kit, no point wrecking a spare alternator to refit used €3 slip rings onto my current. I'm happy to reinstall and wait for it to go. I've driven on solar before .

shamwari wrote: »

As for reinstalling your belt, what make / engine is your van?

Pre-sprinter Mercedes, transporter series. Belt has no adjustment just a tensioned idler pulley and a damper, there's no leverage in there with the rad. in the way, so brute force, ignorance and a ribbon I think.

shamwari

Sir Liamalot wrote: »

Yeah same deal I reckon, except my glow plugs are off before I crank.

Even though the glow plug light extinguishes after a few seconds, the plugs are usually energised for a period after starting to reduce smoke and clatter and generally make the whole starting experience less agricultural. Good luck with the slip rings, it is doable if you've got the bits and the time.

Ah the thick plottens. Yeah that makes sense, the noise is mostly out when the voltage is > 14v.

Um...bout that...The reason the slip rings were shredding was because they're worn through. I finished them off with my sanding trying to get the pitting out. I'm off to get it recon'd today, happy to pay a better man €45 + parts to break his heart with it. I've had enough fighting rusty things just getting into the spare. This one's housing is twice as ceased and screw-heads are a mite rounded, best cut them out and replace at this stage. Might as well get the bearings swapped too while I'm at it. Thanks for the help, much appreciated.

"New" alt. is on, no bother getting the belt on with the ribbon. Squeal is gone, so I guess that was the old dry bearings. Regulator is putting out 0.4v less which I'm not entirely happy about but it's closer to manufacturers spec. and I didn't really run it very long to see if it increased by much. It's the old reg. brushes by the way, now that my slip rings are fatter I thought I'd get the last outtov them. :rolleyes:

Incidentally I learned dipping the hard to reach female spade connectors in a bittov battery acid works great for cleaning the electrolysis/galvanic powdery gloop off. Flatter the battery the stronger the acid.
Best disconnect the battery first though, dipping the alt. +ives in electrolyte seems to throw on the battery fault light and energise a relay on my yolk. (Waiver: don't try this at home, etc. safety gear etc.)

whizbang

You may have overheated the brushes by the constant sparking, but check the springs. These can overheat too, and loose their 'spring', as also the holder can distort.

Ah, I've a collection of regulators...more broken-in the better. I like a good 15.1v in the Winter and 14.5v in the Summer.

Springs are there, they're springy! Anything in particular I should be looking for?

So would a scored brush be bad for the commutator? I thought the brush would just lose the argument if there was one. How would heat affect the brushes?

Holder's fine, there's a smidge of travel in the brushes but I thought that was normal given size of one to thuther. Should the brush stamp be always hidden in the holder? Maybe mine are riding high {edit: come to think of it, that hardly matters until they're substantially worn...hmmm...}

I spoke too soon about the squeal being gone.
Replaced the viscous fan, idler pulley (both soon to meet the maker) and 5mm longer belt was the ticket....a month and half a can of silicone spray later.
Dash blower motor was retired too, somehow it was still working with the commutator spinning off the metal shroud, bearing shredded, 'twas so loud I'd only use it in -5°C

dooroy

If you're using 'old' regulator with new slip rings it could take a while for the brushes to 'bed in ' as it were ; they will have worn to suit the old worn slip rings and can take a while to be 'reprofiled' to make maximum contact with the new rings.
Many moons ago I sometimes used very fine sandpaper to help reprofile old brushes in dynamos etc - was quicker than waiting for it to happen in use .

CJhaughey

I just rebuilt my Alternator, actually a pretty easy job compared with removing the bloody thing!
Got the kit from an Ebay seller in Mayo really fast service and a doddle to fit.
He has a load of Youtube videos under the username Westronicsirl
Really good how-to's.
My kit cost 21 delivered for bearings/slipring/regulator/brushes and solder.

CJhaughey

CJhaughey wrote: »

I just rebuilt my Alternator, actually a pretty easy job compared with removing the bloody thing!

Yeah they're simple creatures alternators. Depends on how old it is. Mine's a 20yo UK import, no turning spanners on mine without a good fight...kinda used to it now. Makes working on more "modern" vehicles a breeze. I'm always surprised to get a bolt out without a blowtorch.

Sometimes I'm tempted to install a bypass to max field voltage bucked to max current @ 14.7v with a thermostatic switch on the stator. Mostly I then decide sleeping dogs and all that.

CJhaughey

Sir Liamalot wrote: »

Yeah they're simple creatures alternators. Depends on how old it is. Mine's a 20yo UK import, no turning spanners on mine without a good fight...kinda used to it now. Makes working on more "modern" vehicles a breeze. I'm always surprised to get a bolt out without a blowtorch.

Sometimes I'm tempted to install a bypass to max field voltage bucked to max current @ 14.7v with a thermostatic switch on the stator. Mostly I then decide sleeping dogs and all that.

Mine isn't much younger, its 16 this year.
But its also Japanese.