Dynamo testing

[Dave Clasper]

Thanks Glang. The CB,B terminal test which came out 14V, was done at 2000rpm (I had this figure in my head for some reason), rather than 2200rpm, so can do this again if will make a difference?.

I also need to be getting higher V across the battery at idle (about 800rpm, in my case), should be around 13.5V?. Never understood this figure, as dynamos don't charge until around 1500rpm, I have read?.

I was driving in stop/start daylight traffic yesterday and noticed that stationery, with headlamps on showing on boot of car in front, my lights did get brighter when engine revved up. I don't think this used to happen.

Also will do good run with lights on check battery V.

 

[glang]

It would have been interesting to see the volts at the 2200rpm but I dont suppose it would have reached the required 15v.

However looking at the manual the dynamo is capable of generating sufficient volts to charge the battery from quite low revs but of course it depends what the current demand is. If the lights are on and the battery needs recharging after a start then of course more revs will be needed.

Yes good to see where volts end up after a longer run.... 

[glang]

This is the relevant part in the manual Dave and indicates that even at 730rpm the dynamo is capable of producing a rapid rise in volts. As I say the current available will be limited but when load is low battery charging should be able to start from anything above tickover...

[Dave Clasper]

Thanks Glang, bit confused, my original tests in this way on 3 different dynamos at around probably 700/800 rpm idle speed, all gave figures from between 5 and 6 v, which according to different books was too low and should be making around 16 v.

I think it was advised on this thread that as long a volts rose steadily up to this figure which mine did up to 16v (at about 1500rpm from memory) and was also going higher with more revs (previous research advice on this was not to take beyond 20v), then probably the dynamo ok

Above info on your last post, does not appear to give a specific volts figure as such, though says to not go over 20V and says not to race engine to get a correct V reading and it should be able to give the reading at not more than 730rpm .

I assumed 730rpm was a general idle speed anyway and engine doesn't run well much below this anyway.

they seem to imply though, to raise rpm from a lower idle figure and 730rmp ,shouldn't need exceeding?.

Sorry this dragging on so much and if you want to call it a day on this, I understand completely and thanks so much for your imput.

Dave 

[glang]

Actually looking at it I wonder if thats not a typo (there are a few errors in Triumph manuals) and perhaps it should be 1730rpm. I think 730rpm is pretty low for idle and to run UP to that very unlikely!

My ignition light just flickers on if the revs drop below 800rpm but thats without any extra load on the system. When the light goes out it means the dynamo is producing enough voltage that the difference to that of the battery is no longer sufficient to light the bulb.

For example: battery 12.7v and dynamo 8.8v so difference is 3.9v which across the 12v ignition bulb might not be enough to illuminate it. Obviously the light going out doesnt mean the battery is charging...

Im checking my system out at the moment so should be able to take some readings in the next few days and post them.

[Dave Clasper]

Thanks, your results, may be interesting.

Also would it be worth altering the A.M connections (as you described earlier in thread) so it shows battery current, to give an idea on how its charging?.

If so?, to be clear it would now be. The 2 brown wire spade connection to one of the C.B,B terminals. The first A.M cable running from second C.B,B terminal to +A.M side. Second A.M cable running from - A.M side to single brown wire spade connection.

Is it as simple as this?

Thanks 

 

[glang]

Yes Dave, looking at the Vitesse wiring diagram luckily on this model its very simple to install an ammeter to show just battery current and is just as you say. You might have to swop the connections on the ammeter to get it showing the right way ie. engine stopped, lights on, -ve and after starting and driving off, +ve.

However if you should do this is another matter - charging current is normally pretty low so if you have a 40+ amp meter most of the time it will hardly show anything so difficult to distinguish between charging and slight discharging. Its one reason why manufacturers went to voltmeters on cars as this is a more reliable indicator of system condition....

[Dave Clasper]

Thanks.  I probably won't bother then. I had wondered if with for eg, lights on and on a run, if the battery wasn't charging sufficiently, then it may show the battery current use as neg/- on the A.M.

I'll never get my head around electrickery, mechanical stuff seems much easier to me

[glang]

You can try it Dave but I dont think it'll be very helpful. The best indicator is if the voltage of the battery when fully charged on a good charger (13.5v?) and that of your car when driving with lights on etc are the same. If this isnt the case either you have too much load for your dynamo or a problem with the system...

[glang]

Bit of a hold up with this as my regulator is being temperamental and its the volt control contacts not closing correctly. I clean them and it works then the next time I try theyre open circuit. Im going to adjust the contact gap as described in the manual (different from setting the control voltage) but it might upset everything😨

[Dave Clasper]

Hi Glang. With me not having much time to work on car, and prioritizing more crucial work, I decided to buy a new C.B.

Also a very experienced/knowledgeable person that I trust on the the other site, has always maintained that adjusting them has never worked for him going by the book (and did burn out some wiring on one) on 3 club cars. I wonder if he was unlucky, or also they are so old now that this is causing problems?.

Not had chance to take for a run with lights, etc on yet. To test charging, It's I guess, just to check battery voltage after this type of run with engine off?.

I'm kind of hopeful, as the headlights are getting brighter now with revving up, and the battery didn't need anything like so long on my charger after driving. Bit difficult to gauge a the mo, as only done one drive since new CB fitted and that was around heavy traffic in bristol, where I live.

Let me know how it goes please  

 

   

Edited November 25, 2021 by Dave Clasper

[Dave Clasper]

Forgot to add, good luck with fettling it

[Dave Clasper]

Took car out on a 30 mile run with headlights on (except at traffic lights and hold ups).

Battery voltage next day (after settling) was 12.8 volts, which I assume, shows the battery has been charging. Not sure if charging is perfect, though appears much better than before.

How's your tinkering with it going Glang?

Ta Dave

[glang]

That sounds pretty hopeful Dave. Mines fighting still as I havent been able to get the regulator to work consistently. Ive adjusted the voltage control relay contact gap which wasnt right and now its awaiting testing however if this doesnt do it Ive probably come to the end of the road with this regulator...

[glang]

Greatly pleased to say finally got to test the VR and after setting its voltage it seems to be working well. Havent given it a long run yet but Im pretty confident the problem was the voltage control relay gap which the manual says is set in the factory and shouldnt need adjustment. Mine however had the gap too small between the solenoid and operating arm so the contact couldnt make properly. The solution is to gently bend the fixed contact so they just make with the correct size feeler gauge between solenoid and arm. Then had to adjust the tension on the arm via the setting wheel so that the relay operates and opens its contacts when the voltage gets to 14.7v.

Also checked the cut-out contact settings (these arent so critical as it just ensures the battery cant discharge back through the dynamo when it isnt producing enough power) but as it was ok left the settings as they were👍 

[Dave Clasper]

Well done Glang, I have never read about the voltage control gap. Is that in any manual?, if so, maybe I've have missed it.

Glad you sorted with no cost. Did it take a lot of hours to research about and think out of the box, to sort this issue?.

  

Edited March 4, 2022 by Dave Clasper

[glang]

Yes it mentions the gap in the manual but shouldnt change from the factory unless of course the contact faces have burnt or been cleaned excessively. I think mine was always poorly adjusted and then when I cleaned the contacts it stopped them working.

Certainly did read it a few times as I was a bit nervous fiddling with gap rather than just adjusting the voltage setting. Of course you can always just check it without changing anything however if I hadnt found anything wrong Id have thrown in the towel! 

[Dave Clasper]

Did it get sorted Glang?

Just wondering about the warnings about amp meters being potentially dangerous, due to amount of cable load going to and from the gauge.

I assume this same load would be going through the original cable/s anyway?.

Is it more about the A.M cables must be fitted properly/safely? 

[RobPearce]

28 minutes ago, Dave Clasper said:

I assume this same load would be going through the original cable/s anyway?.

You assume absolutely correctly.

Any warnings about ammeters being "dangerous" (or anything else, really) should be taken as either (1) the ignorant rantings of the pub drunkard, or (2) actually intended as a warning against letting the pub drunkard rewire your car. An ammeter carries a fairly large current so it needs fat cables, which go directly to the battery, so you need to be careful to make sure they're properly insulated and won't get chafed. But that's all.

[glang]

2 hours ago, Dave Clasper said:

Did it get sorted Glang?

Just wondering about the warnings about amp meters being potentially dangerous, due to amount of cable load going to and from the gauge.

I assume this same load would be going through the original cable/s anyway?.

Is it more about the A.M cables must be fitted properly/safely? 

Yes all working ok although I may increase system volts a bit more.

With an ammeter I think the main concern is that the circuit is not protected by a fuse. Of course theres always going to have to be an unprotected circuit but by installing an ammeter in it you are increasing the chances of a short to earth (either from a connection or within the actual meter) with potentially disasterous consequences...

[Dave Clasper]

Thanks guys

[Antonnick]

Can I latch on to this thread, because my problem is very similar.

Last week I had my Herald 13/60 of 70 vintage booked in for its bi-annual test - the TüV. The car has been in regular usage but on this occaison (it had to be didn't it?) the ignition light stayed on after starting and only extinguished after about 2 minutes. Thereafter for the 45 minute trip to the test station, it used to come on occaisionally; even on normal driving sppeds, not at idle.

Anyway after the test where it was failed because the seat fixings were  loose, the next day the ignition light wont go out at all. Measured battery voltage with engine running is 12,6 V so this is conformation that it is not charging. Good job that the battery is in good condition.

Now according to the Moss Dynamo video, when you connect the F and D terminals after removing the wires, at idle speed the voltage should gradually increase to 16V but like Dave Clasper, mine records only about 5,5V maximum and stays there. I am therefore a bit confused as to whether the Dynamo really is underperforming??? If it is , I can replace it not a big problem but I want to be sure. I have already taken the fan belt off and run the Dynamo as a motor which it happily does. 

I have a spare control box I can try out ( it is not an original unfortunately so may be suspect) but I do not like just swapping components in the hope that it will solve a problem but rather logically work out what is wrong. 

Edited August 2, 2023 by Antonnick

[glang]

If in the short circuit test you mention your dynamo doesnt easily get to 16+v as you gradually increase the revs theres something wrong with it. The first port of call is its brushes especially because the ignition light coming on has got progressively worse as this is typical of the brushes being worn and their contact pressure getting less and less... 

[Antonnick]

Ok thanks - I did not increase the revs though. According to Moss , the increase should happen even at low revs. Anyway I have the Dynamo on the bench now and have already had a look inside. A bit sooty. The brushes appear to be in good condition and still with plenty of material - about 12mm. I will clean the commutator with Aceton before putting it back together  - the brushes? Best left along I would think - they do move in and out of the holders freely. 

I did forget to mention that the ignition bulb failed yesterday. I do not have a spare so for the moment have used the bulb from the oil pressure warning. 

Edited August 2, 2023 by Antonnick

[glang]

Heres the instructions from the Triumph manual:

It also says the brushes should be replaced when under approximately 8mm in length so yours are good. Does the commutator and the coils all look in good condition, no over heating etc? The field winding resistance (connection F) to earth should be around 6 ohms....