My second diahatsu alternator has just died with the same problem. It seems that the rotor winding has burned out which the very helpful auto electrical company (NAES in Manchester) tell me is most unusual.

Anyone know enough about alternators to know why this might happen? The alternator is fitted to a 1.8 pinto. It only ever sees any stress when it's starting the engine, i.e. I never, or very seldom have the lights on (ok, the odd indicator and very occassionally a brake light ) certainly not enought to stress the alternator I would have thought.

This last failure was accompanied by some significant rattling from within the alternator so I'm not sure if it burned out to such a degree that bits came off it, I doubt that somehow cos the charging light would actually go out above 2,000 rpm.

My wiring harness is from MK and while it was only supplied with 2 wires (Battery and lamp) I can't see that this could cause much of a problem. In fact the first alternator was returned faulty before I'd gotten round to fitting the Ignition feed.

Any ideas?

Thanks

over revoloution from too small a pulley? Perhaps

I took the car to NAES to look at the installation and they said it looked OK.

I'm sure there are other's out there with the same alternator on a Pinto?

Anyone else had the same problem?

It would help me to hear from anyone that running the same set up as me so I can feed this back to NAES...

Cheers

is this alternator one of the small japanese ones? 6mm bolt on output and two other connectors together in "T" formation.

yes

as I have found out, these are wired different from lucas type alternators. the two connectors are for the lamp earth and the energiser wire, so it is possible you wired it up wrong. I cannot remember which one is which, will check tomorow and let you know. I have never known one of these alternators to burn out before, usually its the diode plate that fails, if anything

The two terminals are clearly marked as L an IG so I'm pretty sure that's not the problem. The engineers at NAES had a tester and confirmed that the lamp wire was actually connected to the lamp so they were happy with that, still, any light that you can shed on it will be appreciated.

Cheers

the two terminals are L and IG, they are arranged in a "T", the upright of the t is the L terminal and should be connected to the negative side of the charge warning lamp. the other terminal is the energising terminal and should be connected to a switched 12v source.
the other larger connector is the output and should be connected either to the battery positive terminal or to the starter motor main input.

[Edited on 3/9/04 by hortimech]

Does your battery charge normally (when the alternator was working) ?

Has the battery ever appeared to draine quickly - say overnight ?

When the alternator was fitted and for around 1,000 miles everything worked well.

I'm beginning to think that mangogrooveworkshop may be on the right track with the small pulley.

When they fix it this time I've asked them to fit a larger diameter pully. Unfortunately no-one seems to know what the specification is for this alternator so it'll be a bit hit and miss.

What about those of you who've also fitted one of these onto a Pinto? Am I the only one having this problem?

I've got the Bedford rascal/suzuki SJ10 alternator which is basicaly the same.Not had any probs so far but i've got less miles so i'm watching progress.

quote:

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Originally posted by MK7

When they fix it this time I've asked them to fit a larger diameter pully. Unfortunately no-one seems to know what the specification is for this alternator so it'll be a bit hit and miss.

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Hortimech, you have u2u with my email and postal address.

Thanks

Hello,

A car size alternator would in most cases be ok for up to at least 18.000 rpm, and a small Japanese one maybe a bit more.

Is your pulley lining up properly to secure a smothe run without vibrations? Vibrations might affect the connection between brush and rotor, but i dont know if it could cause some overhetaing in the rotor coil.

It is hard to see why the rotorcoil would burn twice, since it is really not carrying a lot of current, beeing switched on/off all the time by the voltage regulator.

Could you have had a problem with your voltage regulator causing the rotor to be switched on constantly?

Charging lamp going out at 2000 rpm seems a bit high, mine go out at idling, below 1000rpm. Could point to a possible voltage regulator error.

/Hasse

Hortimech,

thanks for sending the spec, very nice service than you


Hasse,
I'll have to do a bit of maths to find out how fast the alternator is actually turning.

From what I can tell, the installation is OK, i.e. the pulleys line up and there's no particular vibration.

The charge light going off only happened after the thing chose to die for the second time.

Russell

quote:

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Originally posted by MK7


The charge light going off only happened after the thing chose to die for the second time.

Russell

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The alternator worked perfectly for a while (1,000 miles) then a rattling sound appeared then a few miles later the warning light came on.

The warning light stays on below around 2,000 to 2,500 rpm then extinguishes so the alternator must be giving some charge. The charge must be very low though, I say this because when the alternator was working correctly the load on the engine could be heard when switching lights / rad fan on. Now neither of these activities causes a change in engine load.

Russell

MK7,
Just a thought.
Have you inspected inside the alternator for mechanical damage, possibly caused by something getting into it?

Cheers,

Colin

I have reread this thread and the only thing that I can think of is that you have wired it up wrong. In the motor trade lucas alternators are common, in my trade (very big expensive lawnmowers) we only see these alternators and they virtually never go wrong. As for the speed its revolving at, I am informed they are used on F1 cars and I think they probably rev harder than your engine

This sounds a lot like my Toyota (Denso) alternator and they wire up totally different to a Lucas type.
It needs a ignition feed to it,and the warning light wire feeds live to one side of your lamp with a diode in have a live to the other side of the warning light as well.
The light goes out when one side becomes an earth,I think(its a bit since I wired it up )but I also think its the method of wiring thats at fault,its suprising how many electricians and mechanics will not know how to wire it up if its an ununusual system, as they only fix them when they are knackerd.I'm a service engineer and fit alternators and repair wiring faults all the time,as well as checking charging systems etc..but until I wired mine I thought they all wired up the traditional way...
DEAN..

You know gentlemen, this all sounds like a very good reason to change to a Lucas 16 ACR, I have had them on almost all the cars I have owned, and never had one go down. Just a thought, hope you get it sorted. ATB Chippy.

quote:

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Originally posted by DEAN C.
This sounds a lot like my Toyota (Denso) alternator and they wire up totally different to a Lucas type.
It needs a ignition feed to it,and the warning light wire feeds live to one side of your lamp with a diode in have a live to the other side of the warning light as well.
The light goes out when one side becomes an earth,I think
DEAN..

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Ill agree with you there,Just had major grief at work when I turned up to repair a JCB Teletruk,which had ate three batteries in two weeks,because another engineer from another contractor had been called out to it he just kept fitting batteries and alternators,I checked it out and realised the dash panel was rusty and the bulb wasn't working all the time, hence no charge light and no charged up battery

I'm sure the wiring is OK because for the last 1,000 miles it's worked well, and the autoelectrical people tested it and said it was right....

As for the chance of something getting inside and causing damage, I'll have a chat with the supplier and try to find out what kind of damage occurred. I recall they said that a plastic separator between the rotor and stator has melted...

I'm wondering if the problem could be caused by heat from the exhaust. With a pinto the exhaust is pretty close to the alternator (2-3 inches in front of and below number 1 pipe), I suspect that most of the other cars have their exhaust on the passengers side???

Sounds like all the smoke has leaked out. All electrical components and wiring harnesses depend on proper circuit functioning, which is the transmission of charged ions by retention of the visible spectral manifestation known as "smoke".
Smoke is the substance that makes electrical circuits work. Don't be fooled by so-called scientists and engineers talking about “excited electrons” and the like. Smoke is the key to all things electrical.
We know this to be true because every time one lets smoke out of an electrical circuit, it stops working. This can be verified repeatedly through empirical testing. For example, if one places a large copper bar across the terminals of a battery, prodigious quantities of smoke are liberated and the battery shortly ceases to function. In addition, if one observes smoke escaping from an electrical component such as a Lucas voltage regulator, it will also be observed that the component no longer functions.
The logic is elementary and inescapable. The function of the wiring harness is to conduct the smoke from one electrical device to another. When the wiring harness springs a leak and allows all the smoke to exit the system, immediately, nothing works.
Starter motors were considered unsuitable for British motorcycles for some time largely because they regularly released sizeable quantities of smoke from the electrical system.
It has been reported that Lucas brand components are possibly more prone to electrical leakage than their Bosch, Japanese or American counterparts.
Sometimes you may miss the component releasing the smoke that makes your electrical system function correctly, but if you sniff around you can often find the faulty component by the undeniable and telltale smell of the smoke. Sometimes this is a better indicator than standard electrical tests performed with a voltmeter.
In conclusion, the basic concept of transmission of electrical energy in the form of smoke provides a clear and logical explanation of the mysteries of electrical components and why they fail.

Yes, yes, I've seen this phenomenon

It happens to people as well.

You see them stood outside businesses sucking on white stick like objects.

Smoke then escapes, this then seems to prevent them from working.

[Edited on 23/9/04 by Rob Lane]

So what you are saying in effect is that the battery is a store house of smoke and presumably the alternator is some kind of fire (which would explain why it gets hot).

And perhaps the reason that the ignition lamp is illuminating is due to a drop in the pressure of smoke somewhere within the system, probably in the area of the alternator which may have sprung a smoke leak?

If this is the case then the problem with the alternator probably stems from the fact that there is a lot of wind rushing around the device and this may have put the fire out.

I think there's a problem with this diagnosis though...

When we had our dog cremated it didn't get any better, far from it in fact. For weeks on end it would lay around the house hardly moving at all. And I think the cremation must have affected its hearing too because in the old days if I threw a ball and shouted fetch, it was off like a shot. Nowadays, as already mentioned, there's no life in the beast at all.

So much for your smoke theory.

Ah no. If you've had the dog cremated then you have created smoke which has escaped up the chimney.

You needed to fill him with more smoke.

This could easily have been achieved by placing a straw in his ar*e and you blowing some of your smoke into him.

This is not always successful though and you may have had to do away with the straw and apply lips directly.

Sometimes though, other dogs may help a stricken dog. This is sometimes seen in the street when one dog is behind another and is pushing it forward with two legs on its back whilst inserting a pink smoke tube.

Other dogs regularily check each other for smoke loss by sniffing for leaks at the rear.

Unfortunately now, he has been without smoke for too long, it's a lost cause.

Normally when a alternator dies like your it´s to high revs.
I´ve seen it before on rally cars.
Also on startermotors that didn´t release from the flywheel.
So i think your problem is solved!

All this talk of smoke!What I can smell is not smoke,although it does start with "S"
DEAN

MK7:

I have discussed this with an experienced collegue of mine, and this seems to be a VERY unusuall problem at least in Europeen alternators like Bosch or Valeo.

We belive that the burned rotor may be the effect of a broken regulator beeing switched on constantly. Have you checked the regulator after having the rotor burned?

The cause for broken regulator after something like 1000 miles may be the heat from the exhaust you meantioned.

The solution in this case could then be a heat shielding plate a few centimeters from the alternator facing the exhaust.

/Hasse

I'll ask the auto electrics company to look at the regulator. The second alternator was a replacement and so the regulator would also be different. I have to ask myself how likely it is that the same fault occurred on two different alternators.

I've measured the diameter of the pulley on the Diahatsu alternator and compared it with the diameter of the original Sierra alternator. The Diahatsu is only 10% smaller than the Sierra and so the speed of the Diahatsu alternator is only going to be 10% greater than the Sierra alternator.

Unless the Diahatsu alternator is designed to rotate at much lower speeds than the Sierra then I suspect the diameter of the pulley is not a problem.

I'll take the car to the auto electrics firm and see if thy have an issue with the heat from the exhaust.

Thanks for your input.

MK7