Dynamo possibly duff? Sorted!!

[Minto]

Hello all
While out on a quick ride today before work I noticed that my ameter was kind of static, so I checked my headlamp and found I had no lights, so i pulled over to check properly, all I was getting was a very faint pilot/side light and nothing from the headlight bulb (LED type) or tail light/ brake light.
I’ve had a quick look with a multimeter when I got home, I’m getting a reading of just 3.6 volts at the battery, (when running and no real difference when revved). I also bridged the D & F terminals on the dynamo and put a meter between that and the dynamo body. I got virtually no reading at tick over (0.5/6) but when revved the reading rose proportionately up to around 18/ 19.
I was thinking that for a 6v system this is very high, obviously this is straight out the dynamo and before it gets regulated. Am I going to have to strip the unit and get it looked at or might there be another cause for this??
I’ve never been great with electrickery and get confused easy, so please keep it simple for me. 👍
Thanks in advance.
Jase

[Triton Thrasher]

According to what you say there, the dynamo is the bit that’s working.

[Minto]

TT, 
Well that’s good news.
Regulator then? Or just a broken wire or duff connection somewhere in the circuit?

[Triton Thrasher]

There are actual experts on here, who know a lot about that charging system.  They’ll chime in soon!

I expect you can check that you have continuity from the dynamo to D and F on the regulator.

What type of regulator do you have? Is it the original electromechanical Lucas or an electronic black box?

[Minto]

It’s a Lucas electromagnetic coil type thingy, don’t know how original it is, it has anything else her box of tricks attached to it will h some sticky up things poking out of it.

[morris]

Dynamo putting out 18v should be ok.
Regulator may be out but check the output before and after ammeter. The regulator A output goes over the ammeter before going to the battery, so if your ammeter is out there won’t be any charge.

[Minto]

It’s a Lucas electromagnetic coil type thingy, don’t know how original it is, it has anything else her box of tricks attached to it will h some sticky up things poking out of it.

Krikey, that makes sod all sense! Auto correct is great innit!!!

It should’ve read “it has another box of tricks attached to it, with some sticky up things poking out of it”

Sorry!

[Minto]

Morris
Thanks for that I’ll do some more poking around with the multi meter and report back. Stuck at work til the weekend though.

[Swarfcut]

 Dynamo appears to be OK, but  how good is the battery? Charge it up, see if the lights work. Lights OK? There should be a discharge on the ammeter, so this part of the system is OK. No lights, suspect battery, wiring, connections, battery earth connection, ammeter, switch.
 Disconnect the battery, try the lights, main, dip, pilot, with  the engine running well above tickover.  Working lights mean the dynamo is powering the system via Terminal A on the regulator but the ammeter will not show a reading as it only measures current flow to and from the battery. No lights indicates a wiring fault, dirty connections, particularly the regulator terminals, switch, or a failed regulator. Lights with the engine running above tickover, battery connected but no ammeter reading would point to a duff battery, duff ammeter or a wiring fault between ammeter and battery earth.

Swarfy.

[Minto]

Cheers Swarfy
As always excellent advice.
It’ll be a couple of days before I can look at it properly but I’ll report back what I find. It’s a relief that it seems to not be a cooked dynamo.
Jase

[Greybeard]

I may have said this before but, here I go again: Chuck away the innards of the regulator and fit a DVR2 inside the case; then you will know that that container of Lucas blue smoke is not the cause of your problem.

[Minto]

Sorry GB, what is this DVR2 you speak of?
Jase

[Greybeard]

Sorry GB, what is this DVR2 you speak of?
Jase

If you wait a while, Mike, who makes and sells these little beauties will come along and enlighten you. Basically they are a modern electronic voltage regulator with an excellent reputation; fit and forget. I have mine tucked away inside the old regulator case under the saddle.

[chaterlea25]

Hi All
I do not remember Mike posting on here lately??
Here is a link to his website, http://dynamoregulators.com/dvr2.php

Only this morning one of his regulators arrived to replace the " box of tricks attached to it, with some sticky up things poking out of it”  on the Vincent I am working on ( I like that description  )

John

[Minto]

Cheers for that link John, I’ll take a look after I finish work later. What is the Vincent you’re working on?