TR4/4A Voltage Control Module

I'm struggling with a charging issue on my 1963 TR4. The charging system on the car is stock, but has been converted to negative ground. I also have a thermostat controlled electric fan.Typically, when I start the car, the ignition light will light dimly and then go out if I rev the engine. The ammeter will indicate a slight charge at this point (with the electric fan running). However, after a short time of drive (again with the electric fan running), the ammeter shows a discharge, which I assume corresponds to the current used by the electric fan. If I stop the car at this point and remove the cover from the voltage control module, the cut-out points are open. Revving the engine does not seem to close them. If I physically close them, they'll remain closed for a short time, and then re-open again during driving.

I guess my question is this: Should the cutout points ever open while the engine is running? I thought they only opened when the engine was off and the generator wasn't turning.

Kurt

No, the cutout should open only when the generator voltage drops below some point; I'm not sure what that point is (I think just a few volts), but you should not reach it in normal running.

I'm not sure how much current the electric fan takes. I guess it's conceivable that the generator would not be able to deliver enough current for the fan (plus the ignition system, of course) at idle, but definitely when running at a couple thousand RPM you should not see a discharge and the cut-out should be closed.

Sounds to me like something is wrong with the control box. I suppose a bad connection somewhere is also possible.

The old voltage regulators are directly effected by RPM, that said four things to look at 1- gen. brushes , 2- clean connections 3- drive belt . how old is your battery. As RPM increases power is sent to needed elect. units of your car along with the VR coil to pull in contacts. Recharge battery after starting, ign. coil, gages. Your new fan pulls little your high beams would pull more so what happens then? If your VR and Gen are org to car they can just be tired and braking down with age ( just like many of us ) Most shops will test gen for free maybe just a good service. Also Auto parts stores will test battery's and charging systems for free also. Madflyer

Thanks for the suggestions. Here's a little more info:

The car has just been brought back to life after a 9 year slumber in the garage. The battery is new. The generator and voltage control module were both replaced a couple of years before parking it. This evening when I started the car, the cut-out contacts were definitely closed, and I did not see any indication that the system was charging properly. When I turned on the headlights, the ammeter showed a discharge (approximately 5 amps). I measured the voltage at the battery at around 13.0 volts at 1500 to 2000 rpms, which I assume is too low. I have a copy of the Lucas Generator and Control Box tests and will work through those. Also, I did attempt to clean the contacts with fine sandpaper.

Kurt

Do not confuse Volts and Amps. 13 volts would be OK with Gen. It is the Amps that do the work supplied by Gen. I do not remember max out-put for Gen. but not much A new battery may not have a full charge. If you can put a battery charger on over night, I guessing lead acid battery not an Optima dry cell. A TR 6 alt put out 43 Amps most owners have changed out to 65 Amp Alt and dumped the Lucas. Doing this for the added items fans ect. The Gen does not know what gets the Amps the battery could be the least resistance and take all the Amps or not VR will try. lights would be dimmer fan would go around slower you will not see small dif. Give her a good run at that. And parked for any time a battery tender is a good thing to have, I have a Optima battery and if they get low they can pull more than 90 Amps and wipe out an Alt.
Madflyer

A charged battery, after coming off the charger and sitting for 10 minutes or so will read 12.6v. Realize that most multi-meters will read a couple tenths of a volt off...either high or low. If you connect your multi-meter to a known good battery with a full charge, the battery WILL be 12.6V. That's the physics of the lead acid battery. So...get an idea of how your multimeter reads from reading a good charged battery. Remember the difference, as it is important when checking the control cutout. .1v could be significant. For example...if your multimeter reads 13v on the charged battery, you must remember that your meter reads .4v high, and subtract .4v from all your readings.

Back to your regulator. With the cutout closed, your generator should produce 13.5 to 14.4v. This is controlled by the voltage regulating contact in your control box. 13.5v is what you would like if you drive the car frequently and rather long distances, as it will not overcharge the battery and boil out your water. 14.4v charge would be for those who rarely drive their cars often or far. The higher voltage will charge the battery faster, but on a long trip will boil the water out rapidly.

The cutout is a separate function. when the generator makes a certain voltage above the resting 12.6V battery voltage, it closes the contact so the generator is connected to the battery. That should be about 13V, give or take a point or two. Just as the voltage regulating contact can be adjusted for the charging voltage you want...the cutout contact is also adjustable.

We are finally up to your initial question..."should the cutout open during driving". As long as your generator and regulator are working properly, the answer is no. But, if your generator is not producing the 13v to hold the cutout relay closed, then it could very well trip open. Examples of this in normal driving would be:

1) At a low engine idle and high draw with headlights, fan and everything running, the generator cannot keep up with demand, so voltage falls to battery voltage and the cutout opens, not knowing any better. This is normal and not a worry.
2) You ask for more current than the generator can supply...say electric fan, headlights, high watt stereo system, phone charger, etc...then the generator falls behind, the voltage drops to battery voltage, and the cutout...still not knowing any better...trips open. In this case the system is behaving normally...but you are overloading the generator and could overheat it to death over time.

If you suspect a problem, I would pop the top on your control box and observe the 2 contacts while watching the accompanying battery voltage. Remember to adjust for your multimeter error. Before starting the engine, the voltage contact will be closed, and the cutout contact open. After start on a warm engine, the cutout will likely remain open if your idle is under 1000rpm. . Slowly rev the engine and note when the cutout contact closes...it must be more than 13v, but less than 13.3v. If it is not, adjust to bring it into this range. Next, once the contact closes, and with no extra loads on the car (headlights, radio etc) continue to slowly rev the motor until the voltage stabilizes. There will be a slow fluctuation as the contact cycles, but this must be in the range of 13.5 to 14.4v, as we talked about above.

If the test above is good, but you are still getting the red light and low voltage, then either the generator is loosing its "oomph", or you may be over-powering it above its rated load. Of course, if the test is bad, then the control box either needs adjusting or replacement. Best to double check all your connections and run a re-check, though, before condemning anything.

John,

Thank you for the detailed explanation. That helps a lot. I'm still surprised that an increased load can trigger the cut-out to open. I haven't had a chance to mess with it the last couple of days, but will work on it this evening.

Thanks again,

Kurt

Remember that the cutout is merely looking at the voltage present in the system. It doesn't know if the voltage is low due to the engine stopping, going too slow, or an overload. In my experience the generator will usually melt the solder inside before the cutout trips, though, for an overload. The control box is supposed to protect for overloads, but it's never protected my generators.

CJD Has you going through the steps and right on. In my class to get my aircraft A & E cert. we went into all of this. never really used any of it. You say most all elect. is newer to car the lack of use may cause things like the Gen commutator to lose it's ability to generate what is needed as CJD states. I worked on Generators much bigger 15 to 30 KW and a clean commutator was required for max control of equipment it supplied. It could be just a service to Gen will bring it back to full operation Amps. Keep at it Madflyer

UPDATE:

First of all, I really appreciate everyone's help input. I did some troubleshooting/testing this evening, and here's what I have so far:

I started with the Lucas Generator and Control Box Tests booklet.

Test 1 - Disconnect leads from generator and connect voltmeter to D terminal on generator and ground. Voltage was 2.6v at 2,000 RPMs (engine). Passed.
Test 2 - Same voltmeter configuration and link terminals D and F on the generator. At fast idle voltage was around 14v and rose to 16v quickly as I slightly increased RPMs. Passed.
Test 3 - Disconnect D and F at the control box and read voltage between D and ground at 2,000 RPMs. I had no power to the ignition when D and F were disconnected. That doesn't make sense, does it? I further traced the issue to the F lead. With only the F lead disconnected from the control box, the battery seems completely disconnected. No ignition, no lights. Now I'm confused.
Test 5 - I skipped Test 4 because I figured I'd have the same issue as with Test 3 since the F lead would still be disconnected. Test 5 was a static test and it passed. I read the same voltage between A and E on the control box as I did at the battery.
Test 6 - This is where things got strange and reminded me why I decided to go into civil engineering rather than electrical engineering. For this test I placed a piece of card between the cut-out contacts and measured voltage between terminal D and ground. At 2,000 engine RPMs, I read a steady 12.5v. It remained 12.5v as I increased RPMs (no rise in voltage). The correct range is listed as 15.5v-16.0v. I proceeded to turn the adjustment screw. No change. I turned it more. No change. I turned it a lot more (a full turn and a half). No change in the voltage, but I saw a good sized spark at the voltage regulator contacts, and my overhead LED lamp flickered and went out! It's dead, and I can't believe it was a coincidence. After re-reading the test instructions, it states to check the setting by raising the speed from zero after each adjustment. I did not do that. Could that explain why the voltage readings never changed?

So, I turned the adjustment screw back to the original setting (close - I actually left it about 1/8 of a turn clockwise past the original setting). And started checking the voltage at the battery with everything connected they way it should be. The voltage at the battery with the cut-out closed would climb perhaps as high as 13.2 when I increased RPMs to 3,000, and drop to 12.7 to 12.8 at idle. The ammeter in the car would show as high as +10 amps and just short of +5 amps at idle. When the engine heated to the point that the fan kicked on, the ammeter showed slightly + at idle and increased to close to +5 as I increased RPMs. This is kind of what I would expect, no? The contacts seemed to remain closed.

My two questions are:

1. Why does disconnecting the F lead disconnect the battery?
2. How did my car kill my overhead LED light?

Thanks again everyone for your help.

Kurt

Disconnecting the F lead should not remove power to the whole car. I can't see how that would happen unless something is connected wrong.

Re test 6: sounds like the battery is somehow connected to the regulator's crossbar (D terminal) even with the cutout held open.

It really sounds to me like something is connected wrong.

Finally, until you know that everything is connected and responding as it should, there is no point in making adjustments. You'll probably just misadjust things, and have to fix the adjustments later.

What is the color of the wire that goes to fuse that feeds all elect to car Brown ? It should be at VR terminal ( B ) with two wires That would be elect. to car . Might be ( F ) and ( B ) crossed up
( B ) two brown wires ( F ) brown /green ( A ) brown /Yellow ( D ) brown / yellow ( E ) black Ground This for different year but try. Madflyer

Ok. The (D) wire is brown/yellow at the control box and the generator. The (F) wire is brown/green. There is a brown/white wire from (A) on the control box and a brown/blue wire from (A1). There is a black wire from (E). The wire that supplies power to my fan also appears to be connected to (A1), and there is a second wire running from (D) that I assume goes to the red warning light. In looking at the wiring diagram, I can't find anything out of place.

Kurt

Question; How did it work before the FAN ? How does it work with the fan out of the system? Is the fan fused? The reason for these questions is as follows. DC elect. is affected by resentence and wire size. If the fan is wired ahead of the VR and to a relay ( optional ) and fused and then to the thermostat on to fan. It would look like this Gen feeds your elect needed to car ( lights radio Ign. ) and just the battery to fan. If you are going to Pebble Beach Concourse take the gen to a shop and hope they find a problem. We will not question you with an Alt. with built in regulator and more amps. Around $ 100.00 + - stay in the 60 amp range. Staying in the 60 amp as not to over charge your battery if it gets drained down. And last the answer to your problem is out there do not give up. It is 2020 and you have 1963 Tec. Madflyer

Thanks for the help/support. I do a appreciate it. I probably wasn't clear about the fan. I've owned the car for 19 years, and the fan was already installed. The fan does not power through the ignition. It's thermostat controlled and actually stays on for a few minutes after I shut the car down. I replaced the generator about 13-14 years ago, and replaced the voltage control box at the same time. I also installed a radio and switched the car to negative ground. Everything seemed to work fine, and the ammeter would typically sit a little left of "0" (+) with a fully charged battery at normal driving speeds. With the headlights on and the fan running the ammeter was usually right at "0". At some point I may go the alternator route. I'm just not quite ready to give up yet.

So the apparent problem with the charging system started after I recently got the car back on the road after sitting in the garage for several years. The thing I immediately noticed was that when I first started the car, the ammeter would jump up a little and show a charge when I revved the engine a little, but then shortly after I started driving it would drop to zero, and then around -5 amps when the fan kicked in. If I stopped the car and checked the cut-out, it would be open, and wouldn't close even if I increased engine RPMs. If I physically closed them, they would stay closed, but after a short time of driving, they would open back up. I tried cleaning the points, but that didn't seem to help. It's been behaving that way for the past month, since I've had it back on the road. I've just been topping the battery off periodically and not worrying about it too much.

So after last night, it seems to be working much better. I just returned from a 20-30 minute drive, and the ammeter read how I would expect it to - showing slight charge during normal driving. Slight discharge at idle with the fan on.

I'm still very confused as to why I have no electricity to the ignition when I remove the (F) wire from the control box. That makes no sense to me based on the schematics.

Again, I greatly appreciate the help. I've not messed with this car for several years, and I'm finding that I'm have to re-learn a lot. Fortunately, other than the charging problem, the car is running great, and I'm having a ball with it. I think I've put around 800 miles on it in the past month.

Thanks again,

Kurt

Good on you It is always the drive that makes the day. maybe it just needed that a good run my golf is that way. Madflyer