An Alternator success story

[koukouvagia]

 

My alternator (an A127) began to show a dim warning light.  I was pretty confident I’d be able to trace the fault – I did all the usual tests, checked the connections, made sure the belt was tight, verified that there were no untoward voltage losses or unexpected resistances.  Nothing! I was stumped.

At this point I sent for Ed Bowden.  He took one look and with a sharp intake of breath pinpointed immediately the reason.  I’d replaced recently the alternator belt with one of these linked ones.  They appear to be working but are known to slip no matter how tightly they are fitted.

Once a standard belt was put back the problem was solved.  So, don't be tempted to fit one of these. 

Occam’s razor

 

 

 

[Iain_S]

That's surprising. I used a powertwist belt on Gamebird due to the very limited adjustment available, and run it slacker than a standard belt would be. No slipping!

[Quattrodave]

Dont shoot me here, probably been 15 years since I've even seen one but IIRC don't they grip better one way than the other?

 

Edited August 31, 2023 by Quattrodave

[Tracy D'arth]

1 hour ago, Quattrodave said:

Dont shoot me here, probably been 15 years since I've even seen one but IIRC don't they grip better one way than the other?

 

Correct, they have to run the correct way.  See:----

 

https://bbs.homeshopmachinist.net/forum/general/73386-link-belt-direction

 

 

[sueanddaren]

Thats not a Powertwist belt, I think its called a T link belt.

[Tracy D'arth]

16 minutes ago, sueanddaren said:

Thats not a Powertwist belt, I think its called a T link belt.

OK, here is the Fenner instructions, only runs one way.

https://www.fennerdrives.com › FetchFile.ashx?id=871a898f-6050-48fd-bc27-1ae9942697dd

Installation Instructions - Fenner Drives

Travel Direction Make belt endless, around pulley shafts if necessary, by inserting the stud heads of the last links into the corresponding holes and turning heads 90°. Fit belt into nearest groove of the smallest pulley and roll belt onto the larger pulley by hand turning the drive slowly. Fig. 4. The belt may seem very tight, this is normal.

[MtB]

12 hours ago, koukouvagia said:

 

My alternator (an A127) began to show a dim warning light.  I was pretty confident I’d be able to trace the fault – I did all the usual tests, checked the connections, made sure the belt was tight, verified that there were no untoward voltage losses or unexpected resistances.  Nothing! I was stumped.

At this point I sent for Ed Bowden.  He took one look and with a sharp intake of breath pinpointed immediately the reason.  I’d replaced recently the alternator belt with one of these linked ones.  They appear to be working but are known to slip no matter how tightly they are fitted.

Once a standard belt was put back the problem was solved.  So, don't be tempted to fit one of these. 

Occam’s razor

 

 

 

 

 

So, judging by the design of the alternator fan it should be rotating clockwise viewed from the front of the engine, and therefore from reading the belt installation instructions posted by others, the belt is already on the correct way around.

 

If the engine rotates anti-clock viewed from the front, the alternator has the wrong hand cooling fan, I reckon.

 

 

 

 

 

And therefore the belt is on backwards.

 

 

 

[koukouvagia]

1 hour ago, MtB said:

So, judging by the design of the alternator fan it should be rotating clockwise viewed from the front of the engine, and therefore from reading the belt installation instructions posted by others, the belt is already on the correct way around.

 

I'm pretty sure I'd put the belt on the right way.  Also the supplier of the belt specifically said it was for a 1.8 BMC.  I was told by Ed that the rubber link belts are OK, but this fibre type is not appropriate for an alternator.  I've no idea, really, but I'll stick to the traditional belts in future.

Edited August 31, 2023 by koukouvagia

[billh]

I fitted 5 of those "Brammer" belts on the motor drive to a Herbert Capstan lathe, seems to work ok with its 7.5HP motor. Oddly enough there was no adjustment for ordinary V belts, so these  link removable types were a better(and cheaper) option.