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Control Box Question

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oxendine

Jedi Hopeful
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My generator is charging fine. I did the wire the terminals together and attach volt meter in between test. The problem seems to be the control box. I cleaned the points and manually shut them. They stayed shut and voltage was going through them with the dash light out. The problem is they will not open unless it is done manually. I swapped control boxes and manually closed the points. They stayed close for awhile with the dash light out and then opened on their own. My battery voltage at that point measured 14.5 volts which is charged. I have not taken the car out with the light on to see what happens. Not really sure what's going on. Any thoughts?

Thanks, Donnie
 
I think that's normal. The set of points I think you are talking about needs to open when the engine shuts down, to prevent the generator field from draining the battery. They should close when the engine is started...or at least the first time you rev past 1500 RPM or so...and will remain closed till you shut down the engine. The other set of points needs to cycle while the engine speed is up, to prevent over voltage.

So I guess I'd make sure that the set of points you talked about close when you rev the engine, and that they open when you shut the engine down. If they don't, that is usually adjustable...

John
 
CJD said:
...The set of points I think you are talking about needs to open when the engine shuts down, to prevent the generator field from draining the battery...
Click to expand...

Indeed, mine stuck closed with the engine/ignition off -- the light stayed on so I opened the bonnet to see what was happening: The generator had turned into a motor and was attempting to crank the engine! Good thing I like to keep my belt a little on the loose side, even so it wouldn't have been able to do that for very long.
 
I just got back from several blocks of driving with the head lights on and the dash warning light never went off. Not charging. I'm not sure what to look for at this point.
 
There is a small manual with step-by-step troubleshooting procedures at
https://docs.google.com/viewer?a=v&p...Fm&hl=en_US

Usually, when the cutout points refuse to open like that, it means the generator isn't actually working. The points will stay closed and the dash light will go out, but the battery is actually discharging through the generator rather than the generator charging the battery.

First thing I would look at (if you don't care to follow the step-by-step from Lucas) is whether the voltage on the F terminal matches the voltage on the D terminal with the engine running. If the voltage regulator contacts are dirty or burned, they won't pass current from D to F.
 
...another thing to look at is to see if some previous ham-fisted action on your part managed to pull one of the wires off the back of the generator (not that I've ever done that :blush: ) or if a bad connector finally gave up (what most recently happened to me...and easily fixed :rolleyes: ).
 
What type of control box do you have? One with 3 bobbins or one with 2??

Hopefully just overcame a similar issue with my 68 GT6. Between the dynamo and the control box its been an intersting summer. Today was the first time since June that the ignition light has been off with the engine running, and the volts at a proper level.

I have the RB340 control box, which has 3 bobbins: cut-out, current and voltage.

Cut-out is open with the engine off and then closes above a set voltage produced from the dynamo. This will remain closed until a very low voltage is received.

The current regulator is normally closed. The contacts will open above a set voltage.

The voltage regutor is normally closed. The contacts will open above a set voltage.

I believe that the current and voltage regulators will cycle open / closed depending upon voltage. Reason is to 1. prevent too much voltage being sent to the battery and cooking it and 2. to prevent too much current draw from the dynamo and cooking it.

I have some additional publications that might help depending upon the type of control box you have.

If you have to manually close the contacts on either the current or voltage regulator then adjust the contacts.

jb
 
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