dynamo

[frankenstein]

hi..does anybody have any advice on how to do a quick test to see if my dynamo is charging ok on my 1960 bsa a10 gold flash...i do not have a multimeter...a bulb test might be best...cheers

[LJ.]

Frank... Make yourself one of these! the bulb is 12volt even though my bikes electrics are 6 volts. Careful because the 6 volt dynamo is capable of putting out up to about 17 volts so don't rev the bike too hard or the bulb will blow. Sorry its a large picture, it's so you can see how its wired at the base of bulb. Crocodile clip to frame. That'll tell you if the dyna is working or not.

[RichardL]

Frankenstein,

Is that the nickname you want us to use, or would you prefer the use of your first name (which is not known to me)?

Anyway, LJ's bulb doohickey will be helpful and give you the answer as to whether or not the dynamo is working. However, at about 10 GBP you can buy a perfectly acceptable analog, moving coil, multimeter from Maplin or other stores (I am supposing you are in the UK, otherwise, about $20 US at Radio Shack). I noticed that you were (or are) having issues with failing batteries. I failed a couple of cheap gel batteries before following the regulator adjustment instructions in the Haynes manual and have not failed another since. Those instructions call for an analog meter, which is why I named that type. My gut feeling is that you will get a lot of use from the meter, on the bike and around the house, once you own it.

Richard

[frankenstein]

thats superb..i will construct one asap....cheers!

[frankenstein]

hi....yes i will also take a trip to maplins and get the meter and make the bulb device...i have a maplins store only two miles away..i am having trouble again with the bsa...the battery is not charging (nightmare with electronic ignition) which i suspect has been my problem all the time...i put a new regulator on but did not adjust it..i was kind of wishing it would work out of the box...i have a friend with a flash and will borrow his manual to set the regulator up..its a LUCAS RB 108 REGULATOR ...any body out there got any simple set up instructions

[a10 gf]

Hi, setting up the reg is never easy, first of all the device must be in decent shape, then one has to follow the instructions, using a good dose of patience as the most important tool.

I don't have the RB108 info, but I think you can use the 107 pdf: http://www.a7a10.net/manual54/controlboxrb.pdf  http://www.a7a10.net/lucasmain.htm

What about an electronic regulator? There has been some topics about them here lately. Good luck.

[frankenstein]

hi folks...heres an update...i have tested the generator using a voltmeter and the bulb method and there is no electical output..not even a glimer on the bulb...i tried re-polarizing the gen...but still no output...any ideas from now would be great

[a10 gf]

 I suppose the dynamo drive chain is there , and the cabling from the dynamo is ok.

A little reading here http://www.a7a10.net/manual54/generator.pdf gives good directions of how to check the dynamo internals. Basically, 3 parts: brushes\connection plate, armature, field coil.

[LJ.]

Oh dear things are not looking good. It's strippa dyna time I'm afraid, you'll need to give it a clean out and hopefully.... by cleaning the copper commutator carefully with the finest emery cloth and cleaning off muck afterwards, new brushes if the old ones have worn down, you might be lucky to bring it back to life. Look carefully for signs of it having overheated if you had not adjusted your regulator. I'm betting you've cooked your battery and dynamo  usually one segment goes and if your lucky it may be very close to that segment, you might even be lucky to solder that bit carefully. But hey we are not that far yet. Keeping fingers crossed for you!

Brave of you to use a mechanical Reg, they are fine when set up, but a bit of a pig to do so, It would be wise to get a battery status monitor (I hear everyone groaning about me mentioning that again!)

Okay get to it lad, chop chop, fine weather out there and you need to be riding! 

[frankenstein]

me thinks i am going to buy a solid state regulator before i fry another dynamo...or vice versa....are all bsa  a10s of 1960 vintage poitive earth...just so i order the right regulator...me thinks this is ok as suggested by another member of the forum http://www.manortec.co.uk/dvr.htm     cheers

[Brian]

Frankenstein, I fitted a DVR2 electronic regulator to my plunger A10 and it works perfectly. I would certainly recommend them.

For the owners of plunger models, the DVR2 fits inside the old CVC case so there is no visible change.

Brian.

[groily]

Agree with Brian. You can have positive or negative earth - your choice but you do need to specify when you order. Probably it's positive, but changing polarity is no big deal. Which battery terminal goes to the frame at the moment? That'll tell you which way round you're wired up currently (pardon the pun), and no reason to change it really.

[frankenstein]

what great info from everybody...first step is to strip the dyno and have a look...i hope its just the brushes.....but untill then i am running on a total loss system...it gets me about for now...i cant miss rivington bikers meet on sunday...some great classics up ther today.....a rocket 3 was nice to see....thanks for info on the solid state reg....looks like the one to buy..!

[RichardL]

Sounds rather definitive that the dynamo is bad, but the test where you try to run it as a motor might be interesting before it is stripped down. This is done with the dynamo on the bench. Connect terminals F and D together. Connect one side of a 6V battery to these joined connections and the other side to the body of the dynamo. If the dynamo is basically good it will turn as a motor. Don't allow the connections to stay made for more than a couple of seconds if it doesn't start turning right away. This, to avoid further damage in case there is a short circuit. Even if it does work as a motor, there will probabaly be service to be done (brushes, examination of brush springs, bearings and lubrication, firmness of terminal rivets in the brush-holder plate, tightness of long assembly screws, surfacing of commutator, etc.)

Richard

[a101960]

Even if you are able to make the dynamo "motor" it does not mean that the dynamo will generate. I am afraid that this is not a reliable diagnostic aid. A dynamo will very often motor and not generate. If there is a fault the dynamo will motor due to inertia.That is to say if one or more comutator segments are open circuit the the serviceable ones will allow the dynamo to motor because the open circuit segments will simply be passed over by the brushes due to momentum. You really need a meter to check the dynamo. At about 1000 rpm a reading of 1/2 volt indicates a suspect field winding. A voltage of 1 1/2 - 2 volts would be a suspect armature.