So i got me a jcb.. but not sure what i have, can you shed some light..

[total-tree-care]

hey there people,

as the title suggests, i am not too sure about what i have just baught..
it starts drives and works, but will not charge, i am unsure of the exact model, and think i have a mk1 jcb 3c? is this correct? i am struggling with the wiring for the dynamo, as i am currently having to charge the battery every evening on the bench and refitting in the morning as the dynamo is charging, but until i find out the year and model i dont know what electrical diagrams to follow.. is has a 4 cylinder bmc diesel motor, and manual transmission..

looking forward to the 'experts' diagnosis of model and year.. can post more photos if that helps!

thankyou in advance

Josh

[TrevorJ]

If it charges but goes flat overnight ... and having ruled out the battery is only capable of a "surface charge" (aka a stuffed battery)

By dynamo I'm not sure if you're talking generator or an alternator.

If it's an alternator, chances are the diode pack within the alternator has started to fail which will allow a slow discharge overnight. However if all power to and from the alternator moves through a charge / amp gauge you should be able to note a slight negative reading for an overnight discharge once the machine has been stopped.

Other things which can cause a discharge are insulated items which have inadvertently become grounded to an extent. -> That's why I'd also recommend you take a close look at the current / amp gauge for an insulation failure on the input posts.

[Joes1989]

You've got yourself a 3C MKI couldn't help with the year or anything though sorry!

[total-tree-care]

sorry, i missed a couple letters, the dynamo/generator ISNT charging.. hence me charging the battery after daily use..
and thankyou i thought it was a mk1 3c, great to get some clarification,

[essexpete]

Can someone remind me of the difference between a 3C and a ? The OP's is based on a Nuffield so probably a 1965-67, someone will put me right!

[TrevorJ]

There are a lot of options then.

It's probably simplest to make up a test rig to test the alternator – which separates any issue being connected to the rest of the wiring in the machine. (unless it's a generator where it's a bit more difficult as the regulators are usually back behind the engine.)

A quick run through common faults in alternators I've struck are;

The brush /es are stuck or one of the springs are rusted / broken
The brushes are worn out.
The bearings are worn / full of dry grease, which allows vibration which upsets brush contact the field isn't powered correctly. (That's the small light in the dash, which provides a little power to energise the fields, and are self powered once the alternator reaches an output suitable to power the fields )
The field is weakly polarised or has lost all polarisation.
The regulator is faulty
The internal diode pack needs testing and servicing. Sometimes with severe corrosion, it may just be poor contact between the aluminium plate and the rest of the circuit.

[total-tree-care]

i am pretty sure the old girl has a dynamo.. it is a lucas unit, with numbers dm10 c3 and then a small silver plate with 4268 on it..
there are 2 wires connected to it, but one of them goes to the control box but isnt connected any where.. the green power light (ignition) works, and lights up, but the red one next to it is not illuminated at any time, i will run 12v to the red one to see if the bulb is blown, but the wiring seems to be botched together, with alot of the wires being of the same colour behind the dash.. the only thing that seems to definatly work is the start button, green lamp, small switch that turns ignition on, and the starter motor, other than that the electrics are useless..

in order to run the dynamo as a stand alone unit what is involved, im sure its not as easy as finding the wire with 12v and hooking it up to the battery.. dynamo's are a little before my time, and i am not sure where to start.. any input will be greatly appreciated,

Thankyou once again
JOsh

[TrevorJ]

ok so i have a mk1 jcb 3c, starts on the button, but for the love of me cannot fathom what the hell the previous owner has done with all the electrickery...

the belt driven dynamo produces current from both terminals!
the motor starts on the button!!
but no power makes it back to the battery
i have replaced the non functioning charge light and that now stays illuminated whilst running, so defo no charge..
the old jcb wiring diagram shows things that i dont have, and on the flip side doesnt show what i do have..
the ammeter i have is connected to the power on the starter motor, and the other terminal to A1,

so from what i can work out there is a non original control box/regulator, that is a normal FADE type, albeit i have A1/A/F/D/E/
there are connections to this box but other than the earth they are all the same red coloured wire, and it is proving difficult to trace them back..

so the question i want to put to you guys is.. what is the simplest way to pull power from the old school dynamo to the battery with a working indicator light.. im sure there must be a simple wiring solution to this problem..

LOOKING FORWARD TO YOUR REPLIES GUYS, THANKYOU IN ADVANCE!!

Josh

OK, I wasn't sure if you were just calling anything that charged a dynamo.

Looking for a "c3" I wasn't really seeing anything

I'm thinking it was more likely a c39 but maybe I'm confusing that with a model of starter motor.

Looking at your other thread comment, you've fixed a blown bulb, so you could have hoped that might have fixed things.

It has been a VERY long time since I fooled with regulators and cut outs. They too sometimes need polarisation, and I've stuck that in the middle of the night doing some field work with a battery of questionable starting capacity.

http://www.dynamoregulatorconversions.com/polarising-a-dynamo.php

I'm going to try and attach a file which might help you work through the issues.

[total-tree-care]

ok so i have a mk1 jcb 3c, starts on the button, but for the love of me cannot fathom what the hell the previous owner has done with all the electrickery...

the belt driven dynamo produces current from both terminals!
the motor starts on the button!!
but no power makes it back to the battery
i have replaced the non functioning charge light and that now stays illuminated whilst running, so defo no charge..
the old jcb wiring diagram shows things that i dont have, and on the flip side doesnt show what i do have..
the ammeter i have is connected to the power on the starter motor, and the other terminal to A1,

so from what i can work out there is a non original control box/regulator, that is a normal FADE type, albeit i have A1/A/F/D/E/
there are connections to this box but other than the earth they are all the same red coloured wire, and it is proving difficult to trace them back..

so the question i want to put to you guys is.. what is the simplest way to pull power from the old school dynamo to the battery with a working indicator light.. im sure there must be a simple wiring solution to this problem..

LOOKING FORWARD TO YOUR REPLIES GUYS, THANKYOU IN ADVANCE!!

Josh

OK, I wasn't sure if you were just calling anything that charged a dynamo.

Looking for a "c3" I wasn't really seeing anything

I'm thinking it was more likely a c39 but maybe I'm confusing that with a model of starter motor.

Looking at your other thread comment, you've fixed a blown bulb, so you could have hoped that might have fixed things.

It has been a VERY long time since I fooled with regulators and cut outs. They too sometimes need polarisation, and I've stuck that in the middle of the night doing some field work with a battery of questionable starting capacity.

http://www.dynamoregulatorconversions.com/polarising-a-dynamo.php

I'm going to try and attach a file which might help you work through the issues.

thankyou for sharing both pieces of information with me, i will definatly check the dynamo at first light to check it is doing as is meant to from your link, but sadly the control box of my beast has been changed for a more modern one, so that section was sadly a little irrelevant, but a good read none the less, i will also polarize after i have carried out the initial checks outlined in your attached file,

The main problem seems to be that it has been rewired with just red wire, and even then there are far too many loose wires, so i am looking for a very simple way to create a circuit to feed my battery with juice, if the dynamo does what it says on the tin

[TrevorJ]

By newer do you mean a solid state arrangement or just a smaller more compact unit?

Wiring for a generator should be fairly simple. Auto electrical engineers seem to over think things and require 20 wire bundles where anyone else who does a fair bit of rewiring would get away with just a few better quality wires instead.

(Below the link refers to motorcycles, but the basics are the same and illustrates wiring simplicity.)

http://webspace.webring.com/people/qp/pravg/solidsta.htm