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Alternator replacement

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Alternator replacement

Posted by john_baker2 at January 26. 2017

62 slimline...alternator test as per Al O has failed....the 3 wire stator LU47122A looks pretty rough (I think RM15) and the rotor LU466177 must be about 50 yrs old and is the 70mm size. And it has been converted to 12v but doubtful that it has ever charged!

SO....time for an upgrade

The RM15 has three bolt fitting...possible replacement is the RM23, 2 wire stator...BUT it has more than three mounting holes...so will this fit the RM15 housing??? Or should I be looking at another stator?

Yes I do realise I must change the rotor to 74mm and there appears to be only the one option...RM20, LU54202299.

All help and advise appreciated

regards John

 

Re: Alternator replacement

Posted by robert_tuck at January 26. 2017

Watching with interest as I have to do a similar upgrade on the 67 Atlas.

Re: Alternator replacement

Posted by David Cooper at January 26. 2017

Years back I swapped my damaged 3 wire stator for a new two wire one.  I had no issues with fitting.

My bike also (oddly) came with the wrong (small) rotor.  I think they are unobtainable - but can be remagnetised.  I'm fairly sure you will do someone a favour by selling it on.

As I (and you) found out - the small rotor gives no charge worth having in the large stator.

Regards

David

Re: Alternator replacement

Posted by john_holmes at January 26. 2017

BUT it has more than three mounting holes...so will this fit the RM15 housing???

 

The later ones have 5 holes, you just use the 3 that suit to get the cable routing you need and the remaining 2 are redundant.

Re: Alternator replacement

Posted by phil_hannam at January 26. 2017

The later ones have 5 holes, you just use the 3 that suit to get the cable routing you need and the remaining 2 are redundant.???

Checkout the attachment ..........generally the replacement stators have 6 holes. 5 or 6 holes should make no difference. The extra holes will allow you to position the output cable well away from the chain run.

Attachments

Re: Alternator replacement

Posted by john_baker2 at January 26. 2017

Previously David Cooper wrote:

Years back I swapped my damaged 3 wire stator for a new two wire one.  I had no issues with fitting.

My bike also (oddly) came with the wrong (small) rotor.  I think they are unobtainable - but can be remagnetised.  I'm fairly sure you will do someone a favour by selling it on.

As I (and you) found out - the small rotor gives no charge worth having in the large stator.

Regards

David

THanks David...but the stator is also old and is matched to the 70mm rotor...so it wasn't a case of the gap being too great

regards John

Re: Alternator replacement

Posted by john_baker2 at January 26. 2017

Previously john_holmes wrote:

BUT it has more than three mounting holes...so will this fit the RM15 housing???

 

The later ones have 5 holes, you just use the 3 that suit to get the cable routing you need and the remaining 2 are redundant.

THanks John, that's excellent and another problem resolved.

regards John

Re: Alternator replacement

Posted by john_baker2 at January 26. 2017

Previously Phil Hannam wrote:

The later ones have 5 holes, you just use the 3 that suit to get the cable routing you need and the remaining 2 are redundant.???

Checkout the attachment ..........generally the replacement stators have 6 holes. 5 or 6 holes should make no difference. The extra holes will allow you to position the output cable well away from the chain run.

THanks Phil, so long as it fits that will be fine.

regards John

Re: Alternator replacement

Posted by john_holmes at January 26. 2017

There are 6 holes in the stator, but one is used for the cable on all current production and is not available for the mounting stud, hence 5 holes left for the studs. See attached image. Think its one of the Wassell mods to reduce variations, they now make only one width of rotor when there were at least 2.

Attachments

Re: Alternator replacement

Posted by john_baker2 at January 26. 2017

Previously robert_tuck wrote:

Watching with interest as I have to do a similar upgrade on the 67 Atlas.

 

OK Robert, decisions made...

the electrics  have already been changed from 6v to 12v but the original single phase 3 wire alternator setup retained and using a Boyer Powerbox ( none of my doing as have only just obtained the bike)

the 62 model had the smaller 70 mm rotor...seemingly not available now and why go back to 6v anyway!....So the upgrade starts by going to the 74 mm rotor which is Lucas RM20 LU54202299 and fits the 19mm shaft...and appears to be correct for a selection of stators.

the chosen stator is Lucas RM21 LU47205  which is 12v single phase 2 wire rated at 10amps....and has the wider selection of mounting holes(as per my earlier query)

When parts arrive and if any problems I'll post details.

regards John

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