The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Tone on 26.10. 2009 21:36

Title: Dynamo !!!!
Post by: Tone 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?
Title: Re: Dynamo !!!!
Post by: LJ. 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.
Title: Re: Dynamo !!!!
Post by: Tone on 26.10. 2009 22:57
How exactly do I do that?
Title: Re: Dynamo !!!!
Post by: dpaddock 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
Title: Re: Dynamo !!!!
Post by: RichardL 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.
Title: Re: Dynamo !!!!
Post by: cus 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
Title: Re: Dynamo !!!!
Post by: a10gf on 27.10. 2009 09:43
Do the lamp test, connecting directly to the dynamo's joined 2 wires (yellow+green), see this topic. (http://www.a7a10.net/forum/index.php/topic,627.0.html)
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 (http://www.a7a10.net/manual54/im76-77.jpg) for your model.
Title: Re: Dynamo !!!!
Post by: A10Boy on 27.10. 2009 20:14
You might find this useful.

http://www.youtube.com/watch?v=NV8FFgia7uU&feature=related (http://www.youtube.com/watch?v=NV8FFgia7uU&feature=related)

Title: Re: Dynamo !!!!
Post by: Tone on 29.10. 2009 08:33
If you "flash" the dynamo, how do you know which polarity it's on?
Title: Re: Dynamo !!!!
Post by: bsa-bill 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
Title: Re: Dynamo !!!!
Post by: A10Boy 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.
Title: Re: Dynamo !!!!
Post by: Tone 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?
Title: Re: Dynamo !!!!
Post by: bsa-bill 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
Title: Re: Dynamo !!!!
Post by: a10gf 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.
Title: Re: Dynamo !!!!
Post by: Tone 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.
Title: Re: Dynamo !!!!
Post by: a10gf on 30.10. 2009 20:43
12v, an important piece of information finally emerges  ;)... If you redo the test, try with a 24v, or trough 2x (similar) 12v lamps in series. AFAIR, should give signs of light from tickover, then intensity rising quickly as the revs rises.
Title: Re: Dynamo !!!!
Post by: bsa-bill on 30.10. 2009 20:46
Hi Tone
 A10GF could have a point
All the best - Bill
Title: Re: Dynamo !!!!
Post by: Tone on 30.10. 2009 21:06
How do I wire up 2x 12v in series, or is it easy to get a 24v bulb.
Title: Re: Dynamo !!!!
Post by: a101960 on 30.10. 2009 22:21
Quote
How do I wire up 2x 12v in series, or is it easy to get a 24v bulb.

Tone. A picture is worth a thousand words!
(http://)
Connect 2 12volt lamps as shown in the rough (very rough) sketch. You connect +ve to -ve  +ve to -ve. Yes it would be easier to use a 24 volt lamp, however a 12 volt lamp should be just fine. As others have said if you were able to take the lamp out there is nothing much wrong with your dynamo. Next stop the regulator. If it is an electronic regulator they do not like reversed polarity.
Title: Re: Dynamo !!!!
Post by: Tone on 30.10. 2009 23:20
sorry, on your sketch on the positive side is that two wires that go into the dynamo? I'm not sure because you say to take out the regulator and you wouldn't have to do that if the loom wires are out of the dynamo,or am I on the wrong track.
Title: Re: Dynamo !!!!
Post by: a10gf on 30.10. 2009 23:47
To complement on a101960's sketch, here's the complete connection for 2x12v lamps.
Return does not need to go to dynamo body, any good connection point on frame, engine etc will do.
If you want to get a voltage readout, connect a dc voltmeter somewhere on the cables over the lamps (red circles)
Title: Re: Dynamo !!!!
Post by: Tone on 31.10. 2009 09:09
Thanks very much guys, I'm going to get some more bulbs today and give it a go, I'll let you know how I get on,cheers Tone.
Title: Re: Dynamo !!!!
Post by: LJ. on 31.10. 2009 09:55
Bear in mind that the scrap yard is the cheapest place for bulbs Tone! I got a hand full this week when getting parts for my daughters car. Not sure where the local scrappy is in Brighton though.
Title: Re: Dynamo !!!!
Post by: Tone on 31.10. 2009 17:29
Guy's, I did the light test with two bulbs as you showed me, and, it did exactly what you said, just lighting up on tickover then brightening as I revved up, so the dynamo is ok. I also did the bulb test on the ammeter ok. I have a DVR2 regulator on, the only thing I was thinking of doing is unplug it and wire up the mechanical regulator and see what happens, I'll let you know.
Title: Re: Dynamo !!!!
Post by: a10gf on 31.10. 2009 17:39
Good news always welcome *smile*
Title: Re: Dynamo !!!!
Post by: muskrat on 31.10. 2009 19:25
G'day Tone,
                Could you have fried the DVR2 by hooking up the dynamo polarized to neg earth? I flashed mine before connecting to the DVR2.
Cheers
Title: Re: Dynamo !!!!
Post by: Tone on 01.11. 2009 10:31
Just realized I can't try the old regulator because it's 6v, silly me.
Title: Re: Dynamo !!!!
Post by: flashblack on 01.11. 2009 11:16
Tone,

    You`ve established your dynamo is working, and if you have no output from your regulator, then it must be a faulty reg.(providing your wiring is good) But beware of running the bike with a faulty reg, because you risk burning your dynamo out! I`m talking from personal experience here, my reg failed, and then melted the commutator on my dynamo *sad2* 
I now always keep an eye on the ammeter needle for peace of mind!

cheers Richie
Title: Re: Dynamo !!!!
Post by: Tone on 01.11. 2009 14:13
Thanks Richey,  I've been all over the wiring with a meter set so that it buzzes when you are either end of a wire, and a wiring diagram everything seems ok, I thought these solid state regs where suposed to be bulletproof, I can't see how i've damaged it because when I flashed the dynamo I took the wires out of the dynamo.One point on the fitting on the ammeter the metal u shaped clip screws on the same terminals as the wires which means the current goes accross the contacts is this right?
Title: Re: Dynamo !!!!
Post by: bsa-bill on 01.11. 2009 17:53
They may do depending on the ammeter used but the wires must be insulated from the bracket in some way ( shaped washer maybe ) otherwise your going to get a short across the bracket and to the headlamp shell .

All the best - Bill
Title: Re: Dynamo !!!!
Post by: Tone on 01.11. 2009 18:13
Well i've checked everything I can think of and the only thing it can be is the DVR2, so I'm going to get a new one and hope it's that. Let you know how I get on, thanks you all for your help, Tone.
Title: Re: Dynamo !!!!
Post by: trevinoz on 01.11. 2009 19:52
Tone,
         You can use the old regulator to test. Just take the battery out of the circuit and measure output at the battery leads.
                         Trev.
Title: Re: Dynamo !!!!
Post by: Brian on 01.11. 2009 21:29
Tone, you mention you cant use the old regulator to test as its 6v, at what stage did you go 12v because the DVR2 has to be wired differently for 12v.

If you do suspect the DVR2 I am sure if you send it back to Mike he will test it for you.
Title: Re: Dynamo !!!!
Post by: Dynamo Regulators Mike on 02.11. 2009 18:55
Yes, do not connect the white wire for 12V output. Polarity of battery matters of course, as well as dynamo output polarity. I have tried to make the DVR2 unit as robust against faults as I can, within what is an acceptable price. Bulletproof against all connection faults or whatever is possibly feasible but impractical. Fitting the recommended fuse helps too.

One other point to watch is dynamo belt slipping. I had problems with this initially with Hawker kit. I find the belt has to be really quite tight with the higher load put on the drive by 12V operation.

Tone, I will be more than happy to test your regulator free of charge (bad pun there), or call me to discuss
Title: Re: Dynamo !!!!
Post by: a101960 on 02.11. 2009 21:01
Quote
One other point to watch is dynamo belt slipping. I had problems with this initially with Hawker kit.

That is a very good point. I have had to tighten mine up two or three times, and to be fair, Sean did tell me  that would probably be the case until the belt had settled down. If I were you Tone I would check the belt if that is what you have fitted, and if you have, it is also possible that you could have oil contamination causing the belt to slip. I seem to remember Sean saying that sometimes a mod is required to the inner timing cover to prevent this happening. Should you find oil contamination Sean will do the mod for you.
Title: Re: Dynamo !!!!
Post by: Richard on 02.11. 2009 21:46
Tone,
Just one point about the fixing bracket for the ammeter, if the bracket goes across the two terminals on the ammeter and it is not insulated from the connections themselves then the ammeter will not register any charge or discharge as the bracket will be bridging the circuit, also you will more than likely have a dead short to chassis if the headlamp shell is earthed (presuming it is in a metal headlamp shell), so please check that first.
So with a meter set on continuity and with the battery disconnected and the lights switched of check from the ammeter terminal to chassis and it should read clear i.e. no needle movement.
Richard
Title: Re: Dynamo !!!!
Post by: Tone on 06.11. 2009 19:53
Hi all, Sorted, I managed to fry the regulator, got a new oneall ok now thanks again for all your help, Tone.
Title: Re: Dynamo !!!!
Post by: a101960 on 06.11. 2009 20:50
Tone, glad you got it all sorted, and thanks for letting us no what the fault was.
Title: Re: Dynamo !!!!
Post by: Mosin on 28.05. 2010 23:20
For some time I have had a problem with my charging system cutting in and out intermittently. I've never really got around to fixing this until now (there were always plenty of more pressing issues to deal with). Anyway, I removed the dynamo tonight and as I suspected discovered that the wiring on the back of it was in a fairly poor state and most of the terminal connector screws were very loose. I've cleaned things up and replaced what needed replacing but now stupidly can't remember which wire to connect to F and which to connect to D. A previous owner has strayed from the original colour scheme, so no clues there, and i just have two options available. One wire is attached to a terminal connecting it to one of the brushes. The other one goes back into the body of the dynamo. I've searched around quite a bit on the forum, but I can't seem to find anything which actually tells me which of these wires is which.

Sorry for being dim.

Simon
Title: Re: Dynamo !!!!
Post by: trevinoz on 29.05. 2010 00:42
Simon,
             "D" terminal connects to a brush, "F" connects to the field coil which is inside the body.
Your external wires will have to be traced back to the regulator.
Trev.
Title: Re: Dynamo !!!!
Post by: Brian on 29.05. 2010 07:27
This might help.
Title: Re: Dynamo !!!!
Post by: LJ. on 29.05. 2010 17:51
Look at the regulator and note colour of wires...  FADE = Field, Ammeter, Dynamo, Earth,