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TR4/4A HELP not able to get my TR4 started

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Hmm, maybe it would help some to state a bit of how a DC generator works. Really just two electromagnetic principles are involved, the main one is :

1) Moving a wire through a magnetic field induces electricity in the wire.

and an opposite effect :

2) Current flowing through a wire generates a magnetic field around the wire.

So, the generator generates electricity by moving a wire (actually a whole bunch of wires wound around the armature) through a magnetic field.

Since we need to control how much electricity is generated, the magnetic field is made variable, by using electricity flowing through a wire to generate it.

These effects are pretty weak with just a single wire, so we use lots of turns of wire plus iron to both hold the wires and focus the magnetic field. Everything else is just mechanical engineering (like how to connect moving wires to non-moving wires).

So, the main purpose of the control box is to control how much the generator generates; both to avoid overcharging the battery and overheating the generator (from too much current). In a TR control box, this function is handled by the voltage regulator relay (which doubles as a current regulator as well); which shuts off the current to the field windings whenever the voltage or current get too high.

There is a secondary problem, which is that if we leave the generator connected to the battery with the engine not running (generator not turning), current will flow from the battery through the generator (which after all is conceptually just a length of wire) and discharge the battery. So, the control box also has to disconnect the generator from the battery when the generator is not turning (or turning too slow to be useful). This is the cutout relay.

Ok, maybe we're into Electricity 101 here. Are there any questions?
 
Ok, so I was able to get a bit of time last night and went through testing the generator via the Lucas repair manual. Everything from the generator back to the the Voltage Regulator looks good. I was getting up in the neighborhood of 45 volts when I linked the 2 D and F terminals on the generator, which should be plenty. I'm moving on to Part 2 Test 5 tonight.
 
I was reading through the Lucas manual for Part2 Test5, was hoping someone could clear up a few questions.
1. the line "On no account should these tests be made with the battery in circuit"
Does that mean to disconnect the battery? I assume no but want to be sure.
2.In Test 5 when it says Engine Stationary, that means don't have the engine running, correct?
3. What(where) are the cut out contacts? Is that the space between the core and the armature?
 
1. That means to <span style="font-weight: bold">disconnect</span> the battery.

2. Engine <span style="font-weight: bold">not</span> running.

3. I assume that they are talking about the generator cut-out contacts that are <span style="font-weight: bold">inside</span> the voltage regulator. The service manual does make mention of armature (the part that moves) on the cut-out, but they use the word "coil" rather then core...but this is a TR3 manual.

In my manual for the TR3 regulator, the cut-out is on the right side when viewed with the wire connections on the bottom. I don't know if it's the same for the TR4, as somewhere along the way I believe a third coil was added.
 
1. oh, ok, good to know.
2. as I assumed
3. I actually have the 5 screw TR3 type voltage regulator on my TR4. so the cut-out is the one with more copper wire wrapped around the cylinder and the regulator is the one with just a few wires?
The step says to isolate the battery by placing a piece of dry card between the cut-out contacts. Is that in addition to disconnecting the battery? Or is that essentially removing the battery from the circuit?

BTW, I have been referencing the Lucas repair manual I received from Randall. I will be glad to send you a pdf copy if you want, just DM me your email.
 
OK, I think that some of the info you posted might have been taken too much out of context. I'm getting a bit confused at the moment as far as battery isolation is concerned. Send me that pdf. You have my e-mail access if you click on my forum name and go to profile.

Edit again: I can't tell you which coil has what kind of wire as I don't have a seperate voltage regulator in my TR3 anymore, but it's the one on the right when the wire connectors are at the bottom...wire connectors south, cut-out east. :smile:
 
Ok, just sent you the manual. Just trying to work through tests 5 and 6 in part 2.
 
doughairfield said:
The step says to isolate the battery by placing a piece of dry card between the cut-out contacts. Is that in addition to disconnecting the battery? Or is that essentially removing the battery from the circuit?
Click to expand...
The cardboard removes the battery from the circuit.

The regulator relay is the one where the contacts close when the relay is not energized. The cutout closes when it is energized.
 
In the vibrating-point style voltage regulators that I have messed with (aircraft ones) the reverse-current cut-out contacts are the only ones of the three spools that are held open by a spring. The other two, voltage regulator and current limiter, are held closed by spring. This should help identify the reverse-current cut-out contacts.
 
When they talk about "core" in the control box, they mean the steel rod through the center of the winding on each relay. The "armature" is the part that moves.
 
doughairfield said:
Do I still need to disconnect the battery?
Click to expand...
No, just sticking some thin cardboard (eg matchbook cover) into the cutout contacts is all that is needed.
 
martx-5 said:
I don't know if it's the same for the TR4, as somewhere along the way I believe a third coil was added.
Click to expand...
Just caught that, Art. The TR series continued to use a 2-coil setup until the TR5/250 got an alternator. The 3-coil regulators were used on other Triumphs though, like the early Vitesse, GT-6 and maybe Spitfire.
 
Ok, I made it through tests 6 and 7. On Test 6, my voltage was a bit low, so I turned the adjustment screw on the back of the regulator about 3/4 of turn to bring the voltage up to 16 at 3K RPM. When I did this I began to see some arcing where the fixed contact adjustment screw meets the contact plate above the bobbin core. Is this normal behavior?

On test 7, after removing the card board from between the cutout, I got battery voltage from terminal A and ground. Pass

Now, on Test 8, I did not get the expected voltage increase of .5-1 volt with the engine running, I actually read slightly under battery voltage. So the voltage isn't low, it's just lower than expected. Any ideas here? Is it possible the cutout, though closing is not closing properly and over time the lower voltage drags the battery down?

For test 9, the cutout closes pretty much right after the engine starts, so I assume that passes.
 
The arcing is normal, in fact I'm surprised you didn't see it before. The points close to call for more output from the generator and then open when the output is high enough. When they open, there is some inductive kickback from the field windings that causes the spark. 'Old school' electrics here, the contacts are supposed to just live with the spark.

Your test 8 results definitely indicate a problem, but I'm not sure what. It might just mean the cutout is closing too soon; does the voltage go up if you increase the engine speed just a bit (say 1500 rpm)?

Check the voltage back on the D terminal; if it is different than A with the cutout closed then there is a definite problem with either the cutout contacts or the connections to them.

In case you don't have it, here is the control box diagram.
 
In the diagram above, the "series" coils are the heavy wire you see on the outside of the relays. Since it's just wire, once the cutout closes, the D terminal should be effectively connected directly to A (and A1), so that's why the voltage should be the same.
 
Ok, so the battery voltage does not go up in test 8 when the engine speed increases, just stays at battery voltage.

I tested contacts A and D, with the engine running. A was at battery voltage of 12.55 and D was at 16.5, so they are different. Also to note, during my testing the cutout has always closed about the 3-5 seconds after starting the engine. So is it closing too soon?
 
doughairfield said:
Ok, so the battery voltage does not go up in test 8 when the engine speed increases, just stays at battery voltage.

I tested contacts A and D, with the engine running. A was at battery voltage of 12.55 and D was at 16.5, so they are different. Also to note, during my testing the cutout has always closed about the 3-5 seconds after starting the engine. So is it closing too soon?
Click to expand...
Perhaps, but the important thing to figure out now is why it is not connecting D to A.

Some quick probing at the cutout contacts with your voltmeter should tell you if the contacts aren't conducting (which could maybe be fixed by cleaning and adjusting them), or if there is a broken wire/connection in the unit. The armature (which on my unit is silver-colored) should be connected to D (so you should find the 16.5 volts there), while the contact arm (which on mine is copper colored) should be connected to A.

If you find different voltages right at the relay, then it has to be the contacts that aren't making contact. Check the air gaps per the workshop manual; then clean the contacts with a scrap of newspaper or cloth soaked in carb cleaner. And try again. If that doesn't do it, you may need a new control box.
 
Ok, I tested out the contacts at the cutout with a voltmeter. At first, I was getting low voltage on the contact blade and the armature tongue. I stopped the engine, then restarted just to verify. I don't know if I did something in the original testing, but I noticed that the cutout was opening and closing quickly and the regulator was almost vibrating. I adjusted the regulator output just a touch and all seemed to start working. I had 16 volts on the cutout and proper voltage from terminal D. Also, the Ammeter on the dashboard also seemed to be indicating charge. So of course I drove it for about 15 minutes and all seemed good. Turn the lights on and the ammeter dipped right then back to 0. BUT, now, with the engine at a high idle,~1200 rpm, the green ignition light flashes once every 3 seconds, I don't know what this means. And the more I drive it, the ammeter is bouncing all over the place. Yesterday it even went all the way to the left I guess to indicate max charging and the car shutdown. It seems I'm now having an intermittent problem with the control box now?

This is a total n00b question, but how do I test the battery to see if it is low? To make sure it is not being over charged, or is being charged. Would just testing the battery for voltage tell me this? It is consistently reading 12.5 to just over 13 volts so far. If it is going dead will it register less voltage?
 
doughairfield said:
BUT, now, with the engine at a high idle,~1200 rpm, the green ignition light flashes once every 3 seconds, I don't know what this means.
Click to expand...
I think it means that you're color-blind...or that the wrong bulb is in the wrong holder. Ignition lights are usually red on Triumphs; flasher indicator lights are usually green! :devilgrin:

Seriously, though, that does sound a bit odd....
 
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