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JoeUK

Hello all.

 

I've written this the long way as a guide for anyone who might have the same situation in the future. However my questions are at the bottom, if any polo wizards here could confirm or correct my findings to help me avoid melting or setting fire to things that'd be lovely.

 

Being a cheap date I've gone and bought an early alternator (mk1 golf/MK2 polo type), new old stock for 20 quid which made me happy. In my giddiness I forgot to check if the connections were the same as my mk2f and, of course, they're not 😂

 

Below are the spade terminals on the new alternator that I need to adapt my red and blue wires to.

 

1467499156_IMG_20210605_1335563903.thumb.jpg.da656a6795fc9e96310cfc79a4f6299b.jpg

 

So my research has found I need to chop the ring connectors off my loom, pictured below.

 

560200611_IMG_20210605_1336191463.thumb.jpg.66400e32510c8ff1af2213a9ed37ff11.jpg

 

Red wire (battery +): I can put a female spade terminal on the thick red wire and plug into either of the red circled spades on the alternator. Or better yet have two female spades, one on each terminal, then have the wires both joined to the thick red wire. I figure this divides the current making it a more reliable connection?

 

Blue wire (d+, signal to clocks and small voltage feed to alternator?): This again has a female spade placed on the end and plugs into the blue circled spade on the alternator.

 

Green circled spade: This is the plug the capacitor goes onto, pictured below.

 

295945125_IMG_20210623_1223210452.thumb.jpg.8bb851f389f457dcd4381257421210e0.jpg

 

Questions:

My new alternator didn't come with the capacitor, this ones off my old alt. Does anyone know if I can just use this one or if I need one specific for this alt? Presumably I do need to add one either way?

What's it do? 😂

My old alt was 55amp and the new one 65amp.

 

Will using two spades with two wires bridged into one for the b+ make any difference for the thick red wire supply?

 

Is it true that the blue signal wire also provides a small voltage to get the alternator charging upon startup?

 

Will my polo go boom when I turn the key?

 

Hope this helps others in the future. Thanks for reading everyone.

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It is a little late in the day to answer this, but since you mention it, the purpose of the blue (D+) is for exiting the rotor coil, this is necessary because the rotor dose not (or at least, is not i

https://www.vehiclewiringproducts.co.uk/p-587-alternator-plug-3-pin?search=alter 

Maybe the Interwebs led you astray with self-excitation of generators.   "how  deep puddles are." Once upon a time, before Polos got lowered, I realised a flood I was driving into (a La

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dvderlm

I thought the capacitor is there to suppress radio interference (AM).

Being only 2.2uF or so.

 

The D+ terminal is the warning light output so dash can tell you alternator is not generating (eg main wire fell off or aux belt loose).

 

Yes both fat spades are the same contact for B+ so bridging is fine.

 

There's a plug housing that fits these exactly rather than female spade terminals.

Search for 'Lucas 3pin  alternator plug'. 

And sometimes there's  a metal clip to stop the plug vibrating out.

 

MGB owner's club in Swavesey used to sell the plugs.

 

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JoeUK

Dvdelrm, now you've said that about the capacitor I've realised I mixed the info up. Like you say it's for radio interference and plugged straight on.

I meant to say it was the signal wire for the clocks. I read it might connect to another wire and send a little voltage in to the alternator to start it charging. Allegedly it, or the car, won't work without that initial input upon turning the key. Not that it matters for wiring it in at the plug but something I found interesting, if you can call it that haha.

Chere's for the info that's all been very helpful, I've found that light to be a good indicator of how deep puddles are too, it can't tell when the bearings are gone sadly.

I'd hoped to find a mk2 plug in my loom bin bag but nah so that's great news on a Lucas one instead.

 

nige8021 Thank you for the plug link, much nicer than my DIY attempt. Shal be getting one of those before winter. Once I know my welding won't fall apart, or my engine blow up... Again 😂

 

Thank you both.

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dvderlm

Maybe the Interwebs led you astray with self-excitation of generators.

 

"how  deep puddles are."

Once upon a time, before Polos got lowered, I realised a flood I was driving into (a Landrover had come the other way after all, so should be passable, I thought :retard:) was way too deep for a Polo, when the dipped headlights suddenly lit the water surface from below. I hastily reversed with high revs. In the dry I got out to check the car, which was fine, and talk to the Landrover driver who had stopped, and another wave soaked my shoes and feet. 

 

I have now found a Lucas plug retaining clip on eBay.

https://www.ebay.co.uk/itm/193616914477

 

Enjoy your Polo.

 

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caretakerplus

It is a little late in the day to answer this, but since you mention it, the purpose of the blue (D+) is for exiting the rotor coil, this is necessary because the rotor dose not (or at least, is not intended to) retain any 'residual' magnetism which would initiate charging - so what you say is true.

 

You could also take the opportunity to increase the cross sectional area of the main output cable (Red) to take advantage of the greater alternator output, but unless you have extra electrical loads to 'normal' this is not essential.

Vehicle Wiring Products have a range of cable sizes listed, each with their current carrying capacity.


Regards

 

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