Classic cars forum & vehicle restoration.

[Roger-hatchy]

Went to Margate yesterday.
about 5 minutes into the journey, with all lights on, the ignition light came on, the amp meter read about -2 as per. with the lights on, the lights were still bright, even in the morning twilight.

The ignition light didn't go out with an increase of revs as expected so thought the fan belt might have broken, As I pulled over to check under the bonnet light went out.
Wondered what that was about as everything setled and seemed OK, so continued on my way.

Uneventful journey, about 100 miles.
When time to come home mid afternoon had to have a jump start, started OK with a booster pack.
Stopped to fill up on way home started fine, onto M2 and broke down, embarrassing fuel problems, the DLM don't like diesel.
Still no warning from ignition light.
Anyway recovered to the services on the M2, another embarrassment the recovery driver is a club member

After a few hours of fun, waiting for AA it was found that the battery was flat again, Waiting for friend with jerry can and hose, filled up with proper fuel, started the car after plenty of coughing and smoke.
Pull off the for court and parked to run the car for a while to check all OK when the ignition light came on and grew brighter with an increase of revs.
It was soon notice when checking what the ?? that the regulator points were arcing out and almost welding themselves together.


Ok the fuel problem is nothing to do with the main breakdown, just a coincidence I could have avoided.

My question is what could cause the points to arc out and, or, weld themselves together,
Looking at the coils from the top with the connections away from you it is the right hand coil points that were arcing and even glowing.

I would like to know what the cause was before fitting a replacement,
Could it be a problem with the generator,

Thanks for any help

Roger

[ukdave2002]

Hi Roger

The Field winding insulation in the dynamo may have broken down and so effectively earthing (shorting out) bearing wear in dynamo can cause the armature not to run true; and damage the field windings.

Also check the field connection to the dynamo, it may be earthing somewhere?

This link is a lucas test procedure for the control box.

Cheers

Dave

[Kelsham]

I had a problem with the dynamo on my 1968 Morris 1800, after changing several regulators I gave in and changed the dynamo. It immediately let me set the regulator.
It had kept drifting, the voltage would creep up.

I actually started the problem with an exploding battery.

Regards Kels

[Roger-hatchy]

I did post an answer earlier today and it's gone missing.

Anyway.
Dave
Thanks for that PDF, saved it again.
I think I had a copy off you in 2009 when re-building and re-wiring.

Kels
You got me thinking now, I have four U/S control boxes on the shelf.
cheap import replacements, even though sold as NOS.
I thought it was sorted when I replaced the brushes in the dynamo in 2009.
It's now a few thousand miles later, have I been running on luck? I'll find out soon

Just found, and saved, a PDF to check the dynamo as well, so that's the first job.When the battery is fully charged.

At least it is a bit warmer .

[Roger-hatchy]

I have two conflicting test to check the field windings.

One says to disconect both wires, F and D ok did that, then check resistance with Ohm meter.
Set to 20 Ohm or 200 Ohm Connect to the field terminal and body and the reading should be 6.2 I get 0.00 which I presume to show shorting out.

I have a spare dynamo and that reads the same, this one came with a job lot of ford spares.

The second instruction do not state to remove the wireing, and tell you what voltage to expect.

anyway, Sound like I need both a dynamo and control box, so much for saving for tyres

[47Jag]

Roger,

With the wires disconnected you should measure between the F terminal and the dynamo casing and look for a reading of about 6 ohms (I reckon). Although you should get a similar read between F & D since you would in effect be measuring the field coils in series with the armature. If you measured with the D & F connected you will get 0 ohms as you are measuring the regulator points

Art

[Roger-hatchy]

Hi Art

I did measure with the cables disconected.
I have not been back in the garage since finding the other ?test?
Might not bother with that one

One of the dynamos is on the bench, I think both are original so the insulation might have perished.

Oh well, all part of the fun

I have been measuring all the wiring ready to make a proper wiring loom.
Didn't expect to have to start with new units as well

Roger.