16 replies to this topic

[mbinsaleem]

Hi,

 

I recently took out the wiring loom (front half only) from my Morris Mini Mk1 1963 850cc. Then, I started the re-wiring process with new wires, with the intention to just start the car up. During this process, I also changed the setup from alternator previously installed to a dynamo + control box/cutout. Now, with minimum wiring and no extra electrical components installed (except battery, dynamo, control box, ignition coil, switch, distributor and fuel pump), I am able to start up the car - with the dynamo still disconnected from the control box. However, this will drain up my battery as it is not getting charged.

 

When I connect the dynamo to the control box, and turn on the ignition switch, after about 3-5 seconds, some smoke starts coming out of the dynamo. I immediately turn off the switch without attempting to start up the car again. Could anyone guide what could be the possible issues?

 

Further points to note: Please note that my car is a negative ground, so I have to polarize the dynamo to make sure it works correctly. When I connect a wire between the A terminal on the control box (battery power) and the field terminal of the dynamo (with the field wire disconnected from the dynamo), there is a spark, which I believe is needed to polarize the dynamo. 

 

However, if I wire up the dynamo, and then try polarizing it by connecting the A terminal on the control box with the F terminal on the same box, there is no spark. Could this possibly mean that the control box is faulty? Is there any way to check the control box out of the car, as it is very hard to find a similar car here in which I could place it and check it out.

 

Feel free to ask any further questions that may help in diagnosing this issue.

 

Regards,

Mohammad.

 

[dklawson]

Hopefully Kernow will be along shortly to post to your thread.  He should be able to offer suggestions and observations to help.

 

In the meantime, the only advice I can offer is to remove the cover from the (presumably) new control box.  You will see contact points inside.  Many of the new control boxes ship with a protective coating applied to those points.  Use a piece of cloth soaked in acetone to clean the contacts.  Draw the acetone soaked cloth through the points to remove all the protective coating where the contact points touch.

[mbinsaleem]

Thanks for that. The control box is not new, but I have had it checked with 2 different electricians to verify that it is working correctly (though both have tested it out of the car). In case, nothing else comes to plan, I might have to remove it once again, and run a detailed diagnostic on how the different contacts are behaving with respect to one another...

[carbon]

Mohammed,

 

Are you sure you have the control box correctly connected to the dynamo.

 

On the control box there should be letter markings:

- F should connect to dynamo field terminal (small lucar spade)

- A should connect to main battery positive

- D should connect to main dynamo output (large lucar spade)

- E should connect to earth

 

Hope this helps, and if Kernow Cooper makes any other suggestions go with what he says as he has a lot more experience with car electrics...

[KernowCooper]

Mohammed,
 
Are you sure you have the control box correctly connected to the dynamo.
 
On the control box there should be letter markings:
- F should connect to dynamo field terminal (small lucar spade)
- A should connect to main battery positive
- D should connect to main dynamo output (large lucar spade)
- E should connect to earth
 
Hope this helps, and if Kernow Cooper makes any other suggestions go with what he says as he has a lot more experience with car electrics...

carbon just beat me to it, once you have confirmed the wiring is correct then you need to look at the control box bobbings the one which is normally open contacts with the engine off, if this is incorrectly set and the points are closed then it will turn the dynamo into a motor and try and turn the engine over, obviously it can't and I suspect the smoke your seeing is the dynamo windings smoking, either way the dynamo and control box will have suffered and need replacing.

I once saw a apprentice push the control box normally open contacts shut, and it produced lots of smoke as the contacts arced together and only quick thinking by disconnecting the battery saved a major short/fire

Check the info below to set up a control box

Attached Files

•  Lucas_Control Box Tests.PDF   826.65K   14 downloads

Edited by KernowCooper, 29 December 2015 - 08:41 PM.

[mbinsaleem]

Thanks very much for the tests that you have highlighted. I am also worried that they may need replacing but would only know once confirmed by the tests.

Another related question...the cloth covering on the field windings is somewhat torn in some locations. Could it be that the field wires are coming in contact with the armature? I did try to wrap the armature in a small piece of paper to ensure there is no direct contact with the field windings, but I still see some smoke.

The smoke does rise from within the dynamo though not exactly visible from where it comes precisely.

Thanks,
Mohammad.

[KernowCooper]

I'd not be worried now if the wires are touching the armature (which I doubt) smoke has taken care of that. Run the tests and pay attention to the setting of the cut out/in points setting on the voltage bobbing, but I suspect your current components may not be up to the tests?

[mbinsaleem]

Thank you very much for the test book. It was indeed very useful.

I ran the tests and found that the dynamo was working fine, so I proceeded with starting the car up even with the dynamo giving small amount of smoke. Once started up, that problem subsided, and I haven't seen any smoke since. Maybe it was just the oil traces used to lubricate the dynamo parts that was giving away smoke initially.

So, I proceeded with the tests and found that both the dynamo and the regulator were working fine, except for the final settings of the regulator and the cut-out. There were certain voltage differences from what was mentioned in the tests, but nothing too far off.

However, towards the end of the tests, when I was adjusting the regulator/cutout setting, I faced a new problem. The engine did not turn off even when I turned off the switch ! I had to shut it down by putting it into gear with the brake pressed.

This problem first occurred for a short while but then didn't repeat itself until later in the day. Now with the car off, as soon as I connect the battery, the ignition warning lamp turns on, even though the switch is turned off. What could be the reason for that?

I also noticed that when I turned on the switch, and tried to start up the car with the floor starter, as soon as I pressed it, the ignition light went off and the ignition motor did not do anything.

[tiger99]

It seems to me that the dynamo is connected into the system downstream of the ignition switch, so that when the switch is off, it can still feed the ignition system while the engine is running. Please be very careful when trying to diagnose this fault, as, depending on what is wrong, the dynamo output voltage may go high enough to kill. Best keep the engine revs down, and hands away from the wires.

 

I am not sure how this could happen. Terminals F and D should be wired direct to the control box or regulator, as has been said. A on the control box goes straight to the main battery feed (brown wire to the incoming terminal of the starter solenoid), possibly via an ammeter. E of course goes to a good earth. The ignition warning lamp, which must be small, normally 2.2 watts, goes between the other side of the ignition switch and the D terminal.

 

Now if that is all correct, fitting an excessively large ignition warning lamp (e.g. a 21 watt indicator bulb) will feed enough current from D to the switched side of the ignition circuit to possibly keep the engine running. But I don't think that you would want such a bright light on your dashboard, so that seems to be unlikely.

 

Does your control box have an extra terminal, possibly marked A1, and what, if anything, is it connected to?

[mbinsaleem]

The connections are as you mentioned, though the bulb may be bigger as you mention, so I will check that up. I also have an A1 terminal that is connected to the ignition switch (which is also connected to the A terminal via the fuse box, and the D terminal through the ignition lamp).

However, I have since disconnected the dynamo but the light still turns on as soon as the battery is connected.

Note: I am not using the original wires from the loom, rather have connected all the above wires as per the wiring diagram myself (using Haynes manual).

[mbinsaleem]

Could it be that the ignition switch is not properly earthed? How can I ensure that it is, or is it not necessary? Currently it is not fixed in its original spot...

[dklawson]

The ignition switch does not provide an earth connection to the charging circuit.  Only "hot" wires pass through the switch so that will not be the source of the issue you are dealing with.

[mbinsaleem]

I will be re-wiring the connections today hopefully, and will update again over here. Feel free to suggest any possible solutions/diagnostics...

[mbinsaleem]

Hi everyone,

 

I did go through the above things and here are the findings:

 

1. The bulb indeed was a bigger one (around 25W), so removed that from the circuit. However, the problem still remained with the ignition switch being by-passed somehow and the car remaining in "on" state. What was interesting was that in this state, the starter motor was not working at all with the floor start button, so no way to start up the car, except by cranking (which I did not do).
2. The problem seemed to be resolved when I took out the cable connecting the D terminal on the regulator with the ignition switch (dynamo was already disconnected from the circuit for this diagnostic testing). Once I had done that, the switch was working once again, as well as the starter motor. Don't know why this happened, but apparently the D terminal at the regulator was the issue. Any help appreciated in diagnosing why :) 
3. Thirdly, when I tried to connect the dynamo back to the D terminal (with the car off, but the battery connected), there was a small spark whenever the lucar spade terminal and the wire came in contact. Could anyone explain this?

 

On a side note, from the tests that @kernowcooper shared, when I test the voltage being generated by the dynamo (with the field wire not connected), the test results say that it should be 2-4V at ~3,000rpm, while I am only hitting ~1.5V at that point. Any idea how that could be resolved?

 

Once again, thank you very much everyone for your time and help. It really is very useful for me here in Pakistan where subject matter specialists are quite limited

[mbinsaleem]

Any ideas?