Alternators

[SambaS]

[SambaS]

 

*shrug*

[SambaS]

I want to be the man that can mend an alternator. Sadly I ain't yet.

Anyone in the know? From what I can see the only parts that could fail are the bearings, the diodes, brushes and the resistor pack

[Junkman]

From what I can see the only parts that could fail are the bearings, the diodes, brushes and the resistor pack

 

That would be correct, Sir.

[Pillock]

The other thing that can fail is the bloke with the screwdriver putting it back together which in my case would be prime suspect.

[Skizzer]

I know how to break them - just sell the car to Scooters.

 

 

(Someone will be along with a helpful post in a minute.)

[SambaS]

I need a wire brush for my drill as the one on my angle grinder is too angry. There is rust allover stuff I suspect shouldn't be rusty.

 

Point of note: rear bearing spins free, lots of friction in front bearing.

[SambaS]

[mat_the_cat]

I get my bits from here:

http://www.jcrsupplies.co.uk/products/ALTERNATOR_REBUILD_PARTS/ALTERNATOR_REPAIR_KITS_AND_COMPONENTS

 

Probably worthwhile buying a rebuild kit, if possible, so you can replace the lot while it's in bits. Even if not, if you're in any doubt about how worn something is you can just compare it to the new part.

[Rusty Pelican]

Stators go to earth and short out as do the rotors , you need to test both for continuity and earth , A megger set at 250V will do it , sometimes they will show an earth because of damp or crud , wash them both in gunk and dry for an hour in the oven  , 

Check the windings on the stator , probably star connected with 3 leads out , readings between any lead and any other lead should read the same with an ohm meter  , if theres four leads out the star is a neutral , this will be the main test lead and the others will read from this .

Its unlikely to be delta connected but the tests are the same anyway .

All the previous comments apply as well .

Did that make any sense to you 

[SambaS]

Mat, I am so excited! I wondered where new bits came from!!

 

Rusty, a bit yes, Stator? Megger set?

 

I have a Fluke meter :/

[Rusty Pelican]

One other thing , if the rotor has been hitting the stator because of bearing fail ( known as poling ) ie. theres contact damage and scuff marks on both then bin it as its not worth the hassle sorting it out  .

[SambaS]

Rusty: Educate meeeee!

 

This is a:

 

[SambaS]

Windings?

 

[SambaS]

Diode Pack:

 

[mat_the_cat]

Rusty: Educate meeeee!

 

This is a:

 

 

Rotor

 

Windings?

 

 

Stator, which is made up of windings.

 

I had equal excitement when I realised I could repair rather than buy an exchange unit!

[Rusty Pelican]

Mat the cats on it , outer slip ring on the rotor looks quite worn and are a right arse to change but it will probably plod on for a good while yet .

Just for info ,

The rotor windings create the voltage , 

The stator produces the Amps , theres three phases in this or three sets of coils in simple terms , this generates AC or alternating current , hence the name alternator , rectifier or diode pack as its sometimes called converts the AC  to DC ( direct current ) the car needs , the regulator controls the voltage produced by the rotor usually somewhere between 13.8V and 14.4V , Unregulated the volts would possibly peak at 22V and boil the battery ,

As volts rise the Amps will always drop , as the alternator gets hot when running resistance builds up and the Amps drop , sometimes as much as 8A between cold and hot.

[mercrocker]

Slightly off topic, well not totally....but would be interested to know how this goes because I have done nothing but buy shit alternators for the past four years and get about 12.75 months out of the poxy years guarantee...17acr Lucas* I'm looking at you...

[mat_the_cat]

Lucas ACRs are a piece of cake, I did one a couple of weeks back:

http://autoshite.com/topic/15643-korean-cortina-on-the-road/?p=608828

 

Just over £20 for the bits too

[Rusty Pelican]

Bit more info you might find useful or if your just curious 

Warning light worths like so , copied from the net as its written better than my crap English could manage 

 

When you turn on the key, 12 volts is supplied to the alternator's field windings through the idiot light. This gives an indication that the alternator's field circuit is intact, and it also provides the current to start the alternator charging. In fact, the alternator may fail to charge if that bulb is burned out. When the engine starts and gets up to a high enough rpm for the alternator to start putting out voltage, there is a diode inside that takes some of the output voltage and featured back to the terminal that goes to the idiot light. The net result of this is that when the engine is running and up to proper rpm, the idiot light is receiving 12 volts at both ends, which means that the total voltage drop across the light is the zero volts and the light doesn't light.

[SambaS]

Here's one: the alternator when fitted to car had an additional black box a few cm big dangling from a single wire. I've since found a second in my spares, but neither the old Samba Style alternator nor the new Samba Cabrio one have this box. What may it be?

[Rusty Pelican]

Possibly a suppressor for radio interference 

[jonathan_dyane]

External regulator?

[brickwall]

Possibly a suppressor for radio interference 

 

 

This. Sometimes there is two. One other may be for the revcounter.

[SambaS]

As you can see the wire has come orf

 

[Rusty Pelican]

Thats an ignition coil  capacitor ( condenser ) , Its for radio interference suppression.

Its rated at 2.2 micro farad , possibly  get similar from Maplins , they are pennies.

[red5]

What Rusty said.

 

Ironically the regulator on my Fronterror 2.8 alternator has just , well, not.

[TRW]

Just lob it through your local Pub window whilst dressed as Dick Turpin if the rebuild goes FUBAR.

[SambaS]

Adam Ant?

 

I am taking some things to the scrapyard today to weigh in, hopefully in dong so will balance out the cost of visiting my mum, sad but I'm mega skint as have to tax the Opel today. These two identical alternators were destined the same fate as the scrap batteries. BUT I think I will hold off and see if I can repair them yet.

 

Even though they are making my kitchen look untidy!

[scooters]

Now..alternators...,

 

When I find an alternator problem I find the best way to fix it is to get intouch with Nigel Bickel or Mr Bollox and pester them with annoying questions until Nigel's blood pressure reaches sweary levels then the alternator will miraculously repair itself.,

 

 

My xm one needs new diodes.-got a battery drain..!Nige!!!