Author Topic: Dynamo !!!!  (Read 5864 times)

Offline Tone

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Dynamo !!!!
« on: 26.10. 2009 21:36 »
Hi All, Had the A10 off the road for about a month to do various bits, one was to put on a new ammeter, when all together and started the ammeter was showing no charge I tried the test of joining the two wires from the dynamo and putting a meter on them and the body of the dynamo, didn't register any vaults! put the meter on the battery terminals shows the same when revved up! The dynamo was charging before, I've checked the wiring seems ok, the only thing I thought was strange was when I put the new ammeter on the same way as the one I took off wiring wise it went the other way so I had to swap the wires around, anyone got any ideas?

Offline LJ.

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Re: Dynamo !!!!
« Reply #1 on: 26.10. 2009 21:54 »
Hi Tone... Dynamo might just need re flashing if bike has not been run for a month or more, give that a try.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
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1961 BSA A10  650cc Golden Flash-Red

Offline Tone

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Re: Dynamo !!!!
« Reply #2 on: 26.10. 2009 22:57 »
How exactly do I do that?

Offline dpaddock

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Re: Dynamo !!!!
« Reply #3 on: 27.10. 2009 01:22 »
Suspect an open connection within the ammeter.
If volts to ground on one ammeter terminal aren't the same as on the other terminal, the ammeter is faulty (unless they're both zero, in which case you need to swim back upstream until you find six volts to ground).

David
David
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Offline RichardL

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Re: Dynamo !!!!
« Reply #4 on: 27.10. 2009 01:36 »
First, I saw Dave's post before sending out this one. Can't argue with Dave, but in case they help, here are my comments:

I can't say I know that the issue is not demagnetization, but it seems wierd to me. My dynamo sat for 25 years out of use and worked fine after a cleanup and new brushes. However, Lucas does describe the posibility of accidentally reversing the dynamo's polarity by incorrect connection. Here are the instructions for repolarization based on positive ground.

Richard L.
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Offline cus

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Re: Dynamo !!!!
« Reply #5 on: 27.10. 2009 09:42 »
Also, if a dynamo suddenly stops charging, always worth taking off the cap & kick the bike over
& check that it's spinning, if it isn't you may have snapped the chain behind the timing cover, the
chain can break & sit in the bottom of the case & you wouldn't know.... "worth a check"

Cus
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Offline a10gf

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Re: Dynamo !!!!
« Reply #6 on: 27.10. 2009 09:43 »
Do the lamp test, connecting directly to the dynamo's joined 2 wires (yellow+green), see this topic.
A 12v lamp should light up very brightly when you give some throttle. If so, your dynamo is ok.

For testing the Ampere meter, see the very scientific drawing below (6v lamp for 6v system, 12 for 12). Or, using a multimeter in ohm mode and measuring across the ampere meter connections, the reading should in practice show 0 ohm (very low resistance, close to short circuit).

Then check trough the wiring looking at the wiring diagram for your model.

A10 GF '53 My A10 website
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Offline A10Boy

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Re: Dynamo !!!!
« Reply #7 on: 27.10. 2009 20:14 »
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline Tone

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Re: Dynamo !!!!
« Reply #8 on: 29.10. 2009 08:33 »
If you "flash" the dynamo, how do you know which polarity it's on?

Online bsa-bill

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Re: Dynamo !!!!
« Reply #9 on: 29.10. 2009 10:31 »

I might well need to do this in the following month/months, so here's my take on it and if I'm wrong more knowledgeable members will correct me and help us both Tone
i
It will be earthed to whichever side of the battery is earthed (usually positive in our case ) so will be flashed from the negative terminal thereby assuming positive earth polarity.

My mate up the road had this problem with a dynamo that had been refurbished and would not show any charge, it had been set up with the wrong polarity, he flashed it and cured the problem.

All the best - Bill
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline A10Boy

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Re: Dynamo !!!!
« Reply #10 on: 29.10. 2009 11:48 »
Bill you are correct.

When I bought my A10, it was on Neg earth and I wanted it as STD so I reversed the polarity.

I connected the battery, Pos earth, and flashed a wire from the Neg side to the field terminal and that was it polarity reversed.

Thats all you have to do Tone.
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline Tone

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Re: Dynamo !!!!
« Reply #11 on: 30.10. 2009 20:12 »
I tried the light test and I revved up slowlyish the light didn't come on until the revves were quite high, then the light came on and immediatly blew, is the dynamo knakered?

Online bsa-bill

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Re: Dynamo !!!!
« Reply #12 on: 30.10. 2009 20:27 »
Well the bulb is -  did you use a six volt bulb, unregulated the dynamo will generate nearer 12 volt.

I use an SRM belt conversion that increases dynamo revs by 10%, this helps at low revs

All the best - Bill
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline a10gf

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Re: Dynamo !!!!
« Reply #13 on: 30.10. 2009 20:31 »
If a 6v bulb was used and blew, that's a good sign ! Try again with a 12v, around 20+ watt. I suggest to check\clean the brushes, commutator and brush\connection plate, make sure the brushes are moving free under the springs.

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Offline Tone

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Re: Dynamo !!!!
« Reply #14 on: 30.10. 2009 20:37 »
Bill, I am running on 12v and have also a belt conversion from Hawkers,it's just it seems like it needed a lot of revves.