charging problems...

[Svenn Ryen]

Hi guys....

I am having some issues with the charging on my C15A.

It wont charge until I do the polarising on the genny procedure...with a jumpwire between the btt and gen Connections on the voltage reguator. I do this,,it charges, and even if I stop the engine and start it again... But If l leave it of for some time I have to do the jump wire procedure again to get any Reading on the ammeter. ???

Any ideas?

Svenn

[Lang]

Svenn,

Sounds like something in the circuit is Positive earthed (assuming you have negative earth system). Have a look at each circuit for each instrument and lights including coil. Begin with the battery to starter - starter will work the same whether it is hooked up positive or negative and most of the other systems will work either way so you can only tell easily by checking the hook-up for each item.

Really basic thing to check is the ammeter hooked up the right way and not showing discharge when it is really charging. Check this by putting on the lights and if it shows charge it is hooked up backwards.

Is the voltage regulator all wired correctly?

Something in your system is tripping the generator, it is highly unlikely it will be doing this itself.

Lang

[Lynn Eades]

Your generator is not putting out a high enough charge to make the contacts in the regulator to close.
by powering the fields you are making the output high enough to close the regulator points, which open again when the output drops.
It may be as simple as a dirty commutator.

[Lang]

Lynne,

The thing that is really strange is why does the generator polarity change?

I can understand your solution if the generator is not doing its job as you say but swapping from + to - is weird. Maybe Svenn is just assuming this is happening and flashing an already correctly polarised generator while chasing the problem you suggest.

Lang

[motto]

I don't think it's reversing polarity Lang. It appears that the residual magnetism is insufficient to enable a high enough voltage to be developed to pull in the reverse current relay.
The first thing to do, I would think, is to monitor voltage output which should be between 7.2 and 7.4 when charging.
I would like to know the fix for this one as my Dodge has started doing the same thing.
Someone out there has the answer.

David

[Lang]

David,

What about starting at the generator to take each element standing alone. The raw output from the generator should be well over 20 volts. If that is OK it should eliminate the generator and direct attention to the voltage regulator?

Lang

[Lynn Eades]

Svenn, if you drop the belt off, and then supply power to the big terminal, the genny should run as an electric motor. If it will do this, I would clean the contacts in the regulator.
"Motoring" the generator, is a quick way to check it's overall condition. If it won't "motor", then it needs work. If it does, then it's likely the regulator.
A quick way to check if anything is happening is to turn on the headlights. if you then start the engine, with a few revs on, the lights are generally are brighter, because the voltage has risen above battery voltage.

[motto]

Lang

I did a simple check on the generator and it came up ok.This consisted of dropping off the fan belt and pushing the reverse current relay points closed. This is the double set of points in the regulator. Do this and the generator should motor over in the normal direction of rotation. All is good so there must be a glitch (technical term) in the regulator. What this may be I don't know. Faulty resistor perhaps?

Dave

[Lang]

Dave,

Are you 6v or 12v?

If you are 12v there are some fantastic solid state regulators that work with both generator or alternator. About the size of a matchbox so will fit inside the old regulator cover. I don't know enough about them but maybe also available for 6v?

Lang

[motto]

The truck is still on 6 Volts Lang.

Dammit, the thing's been good for 70 years. If I can get it sorted it should see me out.

David

[Lang]

How far do you drive these days? Just carry a spare battery to see you through the day!
Lang

[motto]

Funny you should mention that. I have been carrying a spare battery and jumper leads in one of the side compartments since the problem arose.
I haven't needed them yet because when it appears the thing is not going to work at all, for no apparent reason the genny will come on line and behave normally for the rest of that segment?
Next start and the game's on again. Whatever's wrong it's got to br quite minor.

Dave

[motto]

We seem to have tapped the limits of expertise available on the forum Svenn.

Any progress?

David

[Lang]

David,

You will just have to wait for a real expert. These queries seem to me like a whole bunch of experts standing around staring into the engine bay of a vehicle broken down on a club run. Sooner or later someone will walk up who has actually had that problem themselves (or is a geniune expert) and presto problem solved.

It is still a bit of fun to throw in some experience:

"No generator? Have you tried cleaning the windscreen?"

There are a few good fault tracing ideas above from the guys on this problem. It may not be immediately useful but there is always a little bit to learn from everyone's idea that's what makes clubs and the MLU forum good to belong to. You certainly contribute common sense (except for DUKW wheels on a Morris van!) on a regular basis.

Lang

[universalgrl]

One thing that everybody seems to miss is a bad ground.
Check your ground cables, remove any corrosion, make sure cables or braided straps are in good condition and have good contact with the frame use multitooth lock washers on bare metal.
ground engine to transmission,
ground both engine and transmission to frame separately and don't spare the silicon di-electric compound to prevent more corrosion.

[Lynn Eades]

Roberta, I was thinking about that. the regulator needs a good earth as does the generator.
If the geny motors, I would be checking the points and air gaps in the regulator.

[motto]

I hear what you're saying Lang. My dad had some pearls of wisdom he used to quote when appropriate.
One was, 'Two heads are better than one, even if they're wooden heads',
Another was,'Even the village idiot knows something you don't!'.

Good earthing is a must U.G. That's something that I will look at but I'm usually careful to get good electrical connections even to the extent of running above earth return wires where i'm not sure.
With a 6 Jolt system you can't afford to lose any.

Dave