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Alternater drive

John Cone

Well Known and Active Forum Website User
VOC Member
Finally took the Prince out today after a four week layoff. After loosing electric generating capabilities on the way home in the early hours of the morning, it was time to sort out the belt drive for my 2CV alternater. i've lost count of the number of "v" belts i've gone through since i fitted it. After a call to HPC gears in Chesterfield, givng them the distance between the driver & driven shafts and the ratio required we came up with a pair of matched toothed sprockets and a very slim toothed belt. Thanks to JH in Bury for the bit of machining he did to one of the sprockets. The test is see how long these belts last. Did 50 miles this evening with all the candles glowing and showing a well balance ammeter. Watch this space.
 

timetraveller

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VOC Member
John, when Dick Sherwin and I developed what has become known as the 'Walkernator' I deliberately steered clear of either vee belts or toothed belts. In general vee belts are not intended to go round radii as small as the one on the alternator. Years ago when people started trying to replace dynamos with alternators several people used toothed belts and all the feed back that I ever heard of was that this led to premature failure of the drive system. The problem is that toothed belts cannot slip and the Vincent dynamo drive is rather jerky. My solution was to use multi vee belts which are designed to go round small radii and will give enough slip to take out any harshness of the drive. Several of the users have now done lots of tens of thousands of miles with this system now with no failures. Keep a careful watch on the drive system and be prepared to change to a multi vee belt system if either the teeth on the sprocket or the teeth on the belt start to show signs of premature failure. It is possible that my pulleys might fit your system but the 2CV alternator that I use has a 17 mm diameter shaft rather than the 15 mm one which was used on some alternators and as for what you have for the lower drive system I do not know. If you need to contact me then enw07@btinternet.com will do it.
 

stumpy lord

Well Known and Active Forum Website User
VOC Member
Roger and I,
over the years hve gone through the whole gambit of drive belts for altenators (toothed, Vee belts, and multi vee). Toothed would last from anything from ten miles to about 100, vee belts are better but are harder on the system, multi vees are the beas knees, a true fit and for get system.
hope this helps.
stumpy lord
 

John Cone

Well Known and Active Forum Website User
VOC Member
Hi Dick/Roger
Yes my alternator has a 15mm shaft and as for the dynamo drive side it's a .5 inch shaft. originally i had a 56mm SPZ pulley on this side & a 44mm the other. i was running a Z375 orZ370 belt. When you say use a multi V did you mean a ribbed type belt or 2 seperate v belts? I know that when my Father- in- law B. knope had his Prince,he ran 2x Z375's in tandum but even they gave hassle. I will see how i get on my, annual mileage is only about 5000mls. But your dimensions could come in handy. My e-mail is john@cone.fsnet.co.uk Thanks again John Cone
 

stumpy lord

Well Known and Active Forum Website User
VOC Member
Hi,
using Norman/ dick sherwin system allows you to fit a much larger pulley on the dummy drive and a smaller one on the alternator thus speeding up the alternator. the ones on ours balences the load just above idle speed.
stumpy lord
 

rapcom

Well Known and Active Forum Website User
VOC Member
To resolve some confusion here, use the term poly-V belt instead of multi-V. A quick Google of poly-V will produce pics to illustrate this type of belt used on the Walker/Sherwin system.
Dick
 

deejay499

Well Known and Active Forum Website User
VOC Member
I have fitted a few 'Walkernators' with the sidecar outfits having quite a high load with sidecar headlight or spotlight and even heated grips. Not had the slightest problem with the belts supplied.
 

Len Matthews

Well Known and Active Forum Website User
VOC Member
With my home brewed alternator set-up using a Nipppon Denso unit from a Honda Civic, I started off using a plain vee belt and a Picador (not Vincent aero engine) pulley. At first, although the belt didn't break, it did split on the inside of the vee. I spoke to the supplier about the problem and he suggested using internally notched belts. This was the complete answer as they can run round small diameter pulleys easily and I've never suffered a failure.
 

Robert Watson

Well Known and Active Forum Website User
VOC Member
I've had a J section poly-v on my alternator for about 20 years. I always carry one or two spares and have never had to change it on on the road. 6 rib going around about 1.6 and 2 in pulleys running of a jackshaft in the generator hole. 200 W permanent magnet alternator.
 

timetraveller

Well Known and Active Forum Website User
VOC Member
We use the same 'J' section, 6 rib poly vee belt on the 'Walkernator' as well. When I was doing the design I phoned up one of the manufacturers and ended up speaking to their chief design engineer. I told him what the loads were, exaggerating by stating that we hoped to extract about one kilowatt from a rather jerky drive system, and he said that three ribs would be enough to take the load. As there is no where near a kilowatt of power being consumed this means that we have a factor of more than two over design, which makes me feel comfortable when selling something. I managed to arrange the pulley sizes so that on the 'B' and 'C' twins the alternator is rotating at about double the engine speed. Standard is one and a quarter. On the 'D's with the recess on top of the gearbox I can do better than that while on the Comets the restricted space for the driving pulley, where the dynamo sits, means that I can't quite get about one and a half times the engine speed. Note however that the Comet is lower geared than the twins so that at any given road speed the engine is rotating more rapidly than it would be on a twin.
 
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