Series 2 Charging Light Increases in Brightness with Increase in Engine RPM

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Knysna

Knysna

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11
Location
Seattle WA
Hello, I was wondering if anyone has every seen this situation. I have a 1969 Series 2a with a new bench tested Generator (dynamo), battery also tested good. Start the motor charging light goes out. Increase engine RPM and charging light brightness slowly increases in relation to engine rpm. I have changed out the voltage regulator to a new old stock one and the result was a charging light does not go out at all. Installed the original voltage regulator back again and still same situation as described above. I have been told the points possibly need cleaned on the vr, have not done that yet. Any help would be appreciated, thanks in advance.
 
Almost certainly a problem with your CVC. Is it a two coil box, (Compensated voltage control) or a three coil box, (Current voltage control)? If the latter, a special tool is required to make adjustments and for both you will need a moving coil volt and amp meter and access to the correct setting procedure. In reality a quick clean of the points with a bit of wet and dry paper is about all you can do. Obviously, you should check and clean all connections and make sure all earth connections are clean and tight and fan belt is correctly tensioned and battery is fully charged. CVC adjustment is best left to the experts.
 
Back in the day we never bothered trying to fix a faulty CVC, we would simply replace with a new one but back then they were really cheap, just a few quid. Now I see that they are £150/£160 and very likely of inferior quality to boot... If this was my problem I would convert to alternator, get rid of the feeble DC system altogether.
 
Tall Ratbag said:
Has the dynamo been polarised? The dynamo relies upon having some residual magnetism to start - if that residual magnetism is incorrectly polarised, the dynamo will not act as a generator of electricity.

Some useful links explaining the operation of the dynamo and control box may be found in this thread.

http://www.lotuselan.net/forums/lot...itive-negative-earth-lucas-dynamo-t28654.html
Click to expand...
An excellent point Mr Ratbag, I've only just noticed the OP said it was a new dynamo and as such it might well need to be polarized according to the polarity of the vehicle. If it has been factory reconditioned it is likely to be unpolarized as they all were back in the day.
 
Agree re polarisation, worth doing first, good call. Setting up the voltage reg is quite easy but takes a bit of care, and make sure you check the temp and set to the correct voltages. The set up instructions are often in old car manuals,
 
Forgot to say, clean the contacts carefully with a swiss file to get them flat, then set the gaps first. Even if the contacts are worn they will work if they are clean and the gaps are correct.
 
Hello and thanks for all the information. Here is the current status. I did polarize the dynamo by just touching a few times the small tab on dynamo to the positive of the battery (maybe I should try again). The small tab is a bit loose where it attaches to the dynamo wondering if that could possible be it?

I did change the fuse behind the dash it wasn't burned out but was pretty tired looking. I do notice less increase in the red light at high rpm now actually almost none now but I'm getting no increased voltage at the battery at any rpm.

I did sand and clean the points on both VR's I have with no results. Fan belt is correctly tight and not slipping.

I did test the voltage coming into the VR on the dynamo (Generator) side. Using a voltage meter, placing the negative of the tester on the negative on the VR and the postive on the imput from the dynamo with the following results. At idle I'm reading 11.4 volts and with increace in engine rpm about 11.7 volts.

With a fully charged battery 13.1 volts I did three short 20 minute test drives at night will lights and heat on. I then tested battery after returning, first 12.80 volts, second 12.5 volts and third 12. 3 volts. I just don't think I'm getting any charge.

At this point I'm leaning toward dynamo not putting out enough volts but I'm really not sure and frustrated.

Any help appreciated...
 
Have you set up the VR since you polarised the dynamo? Is it s 2 or 3 coil unit - 2 coils are reverse current and voltage, 3 are reverse current, voltage and current. Do you have set up instructions?
 
Knysna said:
Hello and thanks for all the information. Here is the current status. I did polarize the dynamo by just touching a few times the small tab on dynamo to the positive of the battery (maybe I should try again). The small tab is a bit loose where it attaches to the dynamo wondering if that could possible be it?

I did change the fuse behind the dash it wasn't burned out but was pretty tired looking. I do notice less increase in the red light at high rpm now actually almost none now but I'm getting no increased voltage at the battery at any rpm.

I did sand and clean the points on both VR's I have with no results. Fan belt is correctly tight and not slipping.

I did test the voltage coming into the VR on the dynamo (Generator) side. Using a voltage meter, placing the negative of the tester on the negative on the VR and the postive on the imput from the dynamo with the following results. At idle I'm reading 11.4 volts and with increace in engine rpm about 11.7 volts.

With a fully charged battery 13.1 volts I did three short 20 minute test drives at night will lights and heat on. I then tested battery after returning, first 12.80 volts, second 12.5 volts and third 12. 3 volts. I just don't think I'm getting any charge.

At this point I'm leaning toward dynamo not putting out enough volts but I'm really not sure and frustrated.

Any help appreciated...
Click to expand...
1. So, we can assume you have negative earth, yes or no? This is important, please answer.

2. Polarizing your dynamo: with dynamo fitted attach a wire to the live side of your battery and flick the other end several times against the "F" terminal on the dynamo. "F" terminal being the little one. They often do feel a little loose where they come through the end plate, as long as the insulation is sound and it is connected inside to the field windings you should be ok.

3. Disconnect the "D" and "F" connections at the CVC. Connect a voltmeter between "D" lead and earth, Run the engine at approximately 1500 RPM. Voltmeter should read 1.5 to 3 volts. Now connect ammeter between the "D" and "F" leads. Run the engine increasing revs until the voltmeter reads battery volts. Ammeter should now read 2 to 3 amps. If different readings are obtained repeat these tests direct at the "D" and "F" terminals of the dynamo. If correct readings are now obtained, you have faulty wires or connections between dynamo and CVC.

Make sure that the earth connection to your CVC is clean and sound. ("E" terminal). You can attach a temporary earth lead to a good earth point to test this.

You can also remove the dynamo and connect it up to the battery. Earth to the casing and the live lead to BOTH terminals. The dynamo should "motor" and there shouldn't be excessive sparking at the brushes. (Too much sparking means worn or poorly contacting brushes). This test is NOT a sure proof that the dynamo should be charging properly but it is a good test of the brushes and commutator.
 
Last edited:
Extreedoc said:
1. So, we can assume you have negative earth, yes or no? This is important, please answer.

2. Polarizing your dynamo: with dynamo fitted attach a wire to the live side of your battery and flick the other end several times against the "F" terminal on the dynamo. "F" terminal being the little one. They often do feel a little loose where they come through the end plate, as long as the insulation is sound and it is connected inside to the field windings you should be ok.

3. Disconnect the "D" and "F" connections at the CVC. Connect a voltmeter between "D" lead and earth, Run the engine at approximately 1500 RPM. Voltmeter should read 1.5 to 3 volts. Now connect ammeter between the "D" and "F" leads. Run the engine increasing revs until the voltmeter reads battery volts. Ammeter should now read 2 to 3 amps. If different readings are obtained repeat these tests direct at the "D" and "F" terminals of the dynamo. If correct readings are now obtained, you have faulty wires or connections between dynamo and CVC.

Make sure that the earth connection to your CVC is clean and sound. ("E" terminal). You can attach a temporary earth lead to a good earth point to test this.

You can also remove the dynamo and connect it up to the battery. Earth to the casing and the live lead to BOTH terminals. The dynamo should "motor" and there shouldn't be excessive sparking at the brushes. (Too much sparking means worn or poorly contacting brushes). This test is NOT a sure proof that the dynamo should be charging properly but it is a good test of the brushes and commutator.
Click to expand...

Hello

Ok, I've done some working on the rover.

1st. To answer question number one, yes I'm negative earth.

2nd. I have polarized again to verify was done correctly.

3rd. For your third step I have a few question. The first part I did and I'm getting a good reading in the range between 1.5 and 3 volts. Now there are 2 "F" leads. I'm connecting the "D" and "F" leads together but I'm not sure if I should connect to both "F" leads or just one. I did connect to the large "F" lead to "D" and increase revs but did see much volts at all. I don't have a Ammeter in the rover so not sure how to check that.

I also did check the dynamo itself by connecting to the battery negative with my volt meter and with the positive end of the volt meter to the large tab on the dynamo I momently connected the large tab to the small tab and saw voltage spike into the high teens, around 19 volts.

I also did disconnect the ground wire, when I do this red charging light comes on. When I reconnect with engine running I do see a small spark so I feel I do have a good ground and charging light goes out.

What do you recommend at this point?

Thanks in advance,
Jim
 
Hi Jim,
I'm thinking you have the two terminals mixed up. In no wiring diagram that I have checked should there be two leads from the "F" terminal but there are two from the "D" terminal, (on the CVC). One comes from the dynamo and the other goes to the charging light on the dash. Just to clarify: on the dynamo the "D" terminal is the big one, the "F" is the little one.
The test procedures I've given you will show up any fault with the dynamo itself which will then lead you back to this being a CVC fault which instinct tells me is the culprit. Have you taken off and cleaned up all the connections and are they all tight?
John
 
Well maybe its fixed, I think I'm getting some charge. I bought a second used Generator and installed it. I also followed this link polarising-a-dynamo.php to polarize it.
I'm going to have the new generator I purchased tested and see if I had incorrectly polarized it or it was bad. The new V.R. was also using seems to be bad and I'm going to have it tested as well. I'll follow up on the results.
 
Knysna said:
Hello, I was wondering if anyone has every seen this situation. I have a 1969 Series 2a with a new bench tested Generator (dynamo), battery also tested good. Start the motor charging light goes out. Increase engine RPM and charging light brightness slowly increases in relation to engine rpm. I have changed out the voltage regulator to a new old stock one and the result was a charging light does not go out at all. Installed the original voltage regulator back again and still same situation as described above. I have been told the points possibly need cleaned on the vr, have not done that yet. Any help would be appreciated, thanks in advance.
Click to expand...
So I have just been round the same circle over and over - my lamp got brighter but no ammeter change. I went through the whole dynamo check and 2 Dynamos later I found the answer. The "cut out" on the voltage regulator was slightly stuck and not moving....so the dynamo circuit didnt complete and no charge and no ammeter. Once I had got the cut-out moving again the charge light dimmed better than ever and the ammeter was back working. Ps. There is a really nice video by Moss engineering on voltage regulators and adjusting.
 
The charge warning light should come on and go off, not 'get dimmer'
The setup should be that the charge circuit cuts out as you drop to idle so that the dynamo doesn't discharge your battery.
As your revs drop, you'll see an increasing discharge until the cutout trips and the light comes on. If you left it long enough, the sparkplugs will flatten the battery and the engine will stop.. that takes quite a long time though
 
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