'powdering' of alternator belts...

[ruston]

My "bag" is happily suspended,where it is both secure and convenient :icon12: but thanks for the thought...

I just knew ........ I just knew- thats why i didn't say hold your t..imp2:

 

[Barry White]

Replace the whole unit with a rebuilt one theres about 9 diodes in the pack some to do with regulation too and a lot of heavy soldering to the windings. Then theres the voltage regulator a square block filled with resin with 3 or 4 wires coming out to test.

 

[Pants]

My "bag" is happily suspended,where it is both secure and convenient :icon12: but thanks for the thought...

If I were Sir Richard Branson, I'd certainly fly the lot of you out here for entertainment...

 

[Pants]

I had a look at the two old rectifier boards in my spares, both presumably in need of replacement. And yep, those diodes are swaged in or some such - not a simple solder-replacement at all. And of course, they all test fine anyway, but...I musta taken them out of service for SOME reason, right?

Going back to the basic-test setup, though, I noticed, while disassembling the old alternators, that the other removable modular board - holding the brushes and regulator - won't get any connection outside the alternator case unless that small QD terminal (that "small wire") is connected - that's where that terminal connects via a short wire, within the alternator's internal connections. That being the case, only the brushes will be connected to the regulator board, if the "charge light" wire is indeed not landed on a 12V source. So is it really true that the small wire isn't needed for the alternator to charge? Or might it really be that it will still charge, but with no upper-limit on the voltage - so better not run it like that other than for testing purposes?

--Dave

 

[ruston]

The alternator requires an exciter wire (unless it is self exciting) to energize the fields , Best google a wiring diagram to make sure you have it correct.

 

[electron1]

When I fitted a 17ACR Alt to a Ford Escort back in the 70's, the small terminal was indeed for the "Ignition" Light.
Literature at the time suggested that this wire fed the Field windings from the switched ignition supply.

 

[Barry White]

I stated earlier that the small spade conector on the alternator was used as an indicator only and had no other function (this is from personal experience) But 3 other people Peg, Ruston, and Electron say it also excites the wiring checking on google gives mixed reviews but most are for fitting a 2w bulb to excite the alternator.
Maybe I am wrong then? Its deffo worth a try you need a 12v 2w bulb conect one side to the small spade conector on the alternator the other to 12v supply the bulb should light up. Then start up and see if it charges.
Deffo worth a try

 

[Des 56]

I had a 1999 Vectra with no alternator output,could get no output until I renewed the knackered charging lamp
Changed lamp and problem sorted

 

[Pants]

I know, you thought I'd ****ed off...no such luck. Settle in. Long bumpy ride awaits...

I *did* think I'd got it sorted. I went back to the 15-year-old alternator, after doing a sort of ghetto-bench-test, since I didn't really trust the shop that said "the diodes are failing" - they are, I think, the only rebuilder in town, so how's that for an incentive to exaggerate or outright lie...especially knowing he quoted me $180 (GBP118!) to rebuild. But, "Ghetto-bench test," you ask? Clamped it to a workbench, applied +12V from small lead-acid battery to one large terminal, earthed the case to -, and clipped a test-lamp between the "small terminal" and +12V.
The lamp glowed right off, as it should have. Then with a cordless drill fitted with appropriate socket to drive the field, and...at maybe 1000RPM, the bulb dimmed, current flowed, and voltage rose. Wondrous to behold.

"So," concluded I, "...it was just the battery that was knackered all along...and the belt?... well, it must have nearly worn itself out while struggling to charge that old 2008-vintage battery..."

Thus I refitted the alt, drove out with the missus, enjoyed the absence of a charge-light, and voltage-reading of about 13V, and thought all was well.

But all was not well... Returning home in the dark, it was hard to miss that charge-LED, blinding me with it's infernal, mocking glow. Checked under the bonnet on the way home, and...the belt had SNAPPED. We headed the rest of the way home regardless, me gambling on a convenient theory of convection-current circulating coolant sufficiently to keep me below, say, 800F, what with the electric fan being on. (Actually, it was a short drive, so I chanced it, and did get away with it, somehow, though I watched my temp-gauge a lot more closely than the road.)

In the light of the next day, with the belt no longer a visual impediment, and a (slightly) more critical eye, I noticed finally that there was more than a slight roughness to patches on the cheap stamped-steel alt pulley surface. In fact, on close inspection, I realized that it had a patch that was more like 24-grit sandpaper than anything - though that, too, was masked by a glaze of rubber from the belt.

So THAT was it. Eu-freaking-reka.

Ebay hooked me up with a new solid-steel turned pulley, galvanized, and I futzed around with shimming the pulley to get it aligned just right with the pump and crankshaft. Ebay also provided a matched pair (one for later) of new drive-belts at a bargain. I installed this combination just this afternoon, tested it in the driveway, and all was bliss - no squealing, good voltage, even with headlights ablaze.

Took the same trip out as last week - a few miles each way, returning in the dark. (Can you feel it? Here it comes...) On starting, I had that charge-light, but that's normal - it has always stayed on until I rev the engine up a bit, then it's out for the rest of the drive. I pulled out into a long line of traffic, and it took about ten minutes to get moving, so the charge-light stayed on, since I hadn't wanted to aggravate other drivers by revving crazily. But when I finally got out of that jam, there it was again - that unbearable, miserable squeal, as I revved my way through an almost-red light.

Once at home, I checked under the hood. The belt wasn't too loose, nor too tight, but the new pulley was noticeably warm compared to the others.

So..."diodes are failing," after all? Pffft...