TR2/3/3A no leaks, but the generator is not charging

[TR3driver]

'D' is the armature connection, through one of the brushes. It is the power output.
'F' is the field connection, it is how power gets supplied to the field windings (an input).
Both circuits return to ground through the generator case (and for the armature, through the other brush).

Linking them together is not a "short", it just calls for maximum output from the generator. The voltage from the output on D gets fed back into F to supply field current, which produces a stronger magnetic field and hence more output on D.

So test 2 is just wiring the generator for maximum output (with only the generator in the circuit, no leads, no control box), and then checking how much voltage it generates. Test 1 verified the brushes and armature, test 2 is adding the field.

This is still normal operation; the regulator contacts do the same thing (connect F to D) until the voltage or current rises to the limit. But for the purposes of the test, there is no current to worry about and you will be limiting the voltage by limiting how fast you run the engine.

If you don't have an ammeter available to check field current, then check field resistance (engine not running). Terminal F to ground should be pretty close to 6 ohms. Worth checking, because a short in the field windings can allow the generator to appear to work, but the high field current can cause it to overheat and fail later; or overheat the control box. Field shorts aren't especially common, but can happen.

That was actually the final straw that made me decide to go ahead with the alternator conversion this time. The cloth on the original field windings had fallen off and let one wire get loose, to be cut by rubbing on the armature. I robbed some field coils from another unit in the parts bin, without checking to see if they were shorted. Installed on the car, I was wondering why it was working so poorly, when I touched the regulator relay and burned the health out of my thumb! Field resistance was under 2 ohms, meaning there was 6 amps or so flowing through the regulator contacts instead of the usual 2 amps.

 

[sp53]

I had the 6 ohms at the field—but no voltage at the generator with A&D looped at 2000 rpm and volt meter on D with the regulator out of the system. The volt needle wanted to move, but stop at maybe 1 volt, so I hooked up a digital and nothing-- no volts.

 

[TR3driver]

You had over 2 volts without the field connected, right?
So, either your connection is causing a short to ground (possibly missing insulation where the terminals come through the end plate), or there is a bad (high resistance) connection in the armature circuit.
I would double check that something isn't touching the end plate, then it's time to pull the generator off and apart.

 

[sp53]

Yes I had 4 volts with D connected. This Generator is very clean and I had it tested at a commercial shop before I put it on. The guy said it is like new. It has those lugs coming out rather than the spade connectors.

There is something else odd going on, the ignition light was very bright when I first started the car and light popped on hard and too clear and bright. I figured it was the bulbs because I put all new bulbs in 1449 2.2w I think that is the correct watt, but the bulb only says 1449E. Anyways now the bulb is half that bright when the key is turned on and takes a second to glow. Plus the ignition light would not shut off with the key after I tried a second test. I had to unhook the battery to shut the ignition light off, but the amp gauge and fuel gauge responded with the key. Moreover, at the very first start I had nothing at the key, but wiggled and tighten the screws and the ignition light up very bright too bright.

The only thing I did out of the ordinary with the wiring diagram was move one of the white wires over to the starter button from the ignition switch. The switch is of unknown condition, but it seems to work. Plus I added an overdrive relay and I can hear that click.

I am going to pull the generator off and look at it and then that quality shop look also. These guys are the best in town with lots of experience. I have other generators, but wanted to use the lug style for originality.

I hate the car again and the universe for putting through my education!

 

[TR3driver]

On the early generators with the lugs, the field connection is attached to the body (through an insulator), but there is supposed to be a phenolic sleeve over it where it comes through the end plate. The sleeve is just loose, so it can get lost. They also (in my experience) can often break.

With the sleeve broken or missing, the generator will work fine as long as the lug remains centered in the hole. But, it's easily displaced (for example by tightening the nut with a wrench) so it touches the side of the hole, shorting out the field windings.

The sleeve is rarely shown in the diagrams, but here's a photo where you can see it (as a dark section on the lug, which is otherwise light colored brass).

I don't know that is your problem, it's just an example of one way the generator can "test fine" but still not work on the car. And something to check for when you get it on the bench.

Loose wires, like I mentioned before, are another possible intermittent failure.

The D terminal is better insulated, but I have seen the plastic insulator crack when the nut is tightened.

 

[TR3driver]

Also, if you should happen to get bored, you might want to skim through the generator section in this document:
https://drive.google.com/open?id=0B2H2NJt34OffV290bkxKZzdDUlE

One last point, although not your problem now; you want to be sure to use the control box that matches your generator. The later box with the quick connects is also slightly different electrically, and may allow the smaller, early generator (with the lugs) to overheat and damage itself in operation. Somewhere, I've got a note from Lucas warning not to mix them.

 

[TR3driver]

There is something else odd going on, the ignition light was very bright when I first started the car and light popped on hard and too clear and bright. I figured it was the bulbs because I put all new bulbs in 1449 2.2w I think that is the correct watt, but the bulb only says 1449E.

1449 should be a 2.8 watt bulb, slightly brighter than the stock 2.2 watt.

Anyways now the bulb is half that bright when the key is turned on and takes a second to glow.

That could be a symptom of the high resistance in the armature circuit I was talking about. The bulb basically grounds through the armature, but normally the armature is such low resistance that the bulb is essentially full brightness (with the engine not running).

Plus the ignition light would not shut off with the key after I tried a second test.

That seems really odd; I have no ready explanation for that. If it happens again, check the voltage on the 'D' terminal. If you find power there, then the cutout has remained closed for some reason, or there is a wiring problem inside the control box. But if no power there, then there has to be a wiring problem to the light.

 

[sp53]

Randall I want to thank you for the effort you have provided me with on the electrical problems and how these systems work. They have always been a mystery, and when they failed I just throw parts at them until they stopped

The only thing I can think of that would have stopped the generator from working would be in my infinite wisdom, I put some of this liquid copper stuff on the threads that I got from an electrician on a large commercial job I worked on years ago. The stuff could have worked down the threads and past the insulator on the D post then grounded, and it looks like it did; you can see a little in the picture. I cleaned the stuff off, but before I reinstall the generator I want to have it looked at by a second set of eyes—plus I do not know if it could have destroyed the generator or not. It does look like I could swap off parts from a spade connector system and get back to a lug system. Oh the joy of being a purest.

 

[CJD]

Hey Steve...

The quickest way to tell if you have damaged the generator is to connect "D" to "F" to a volt meter. The positive wire on the voltmeter goes to the case. Then just spin it! If it is all good you will read a voltage as it spins. If you are spinning by hand the voltage will be rather low...if you can use a drill it will be much higher. Any voltage reading means the generator should give an output on the car.

Edit...The "F" stands for the field winding. I have been trying to figure out what "D" would be. All I can come up with is that it stands for Dynamo winding?!? You can't hurt anything by grounding the F lug...but you could generate a lot of heat if the D lug gets grounded for any length of time while spinning.

On simple terms, the D is the power lug. But, for the power coil to generate, it has to move within a magnetic field. Thus the Field lug. Putting power to the field lug forms the magnetic field for the power coil to spin within. So, more power to the "F" means a stronger field for the "D" to use to generate more power. Less power to "F" reduces the field for the "D" to work in, so less power.

That's where the regulator comes in...merely to control the power going to the "F" lug, to keep the "D" within certain voltage limits. It just cycles the power on/off to the "F", so the voltage stays in a narrow range.

The generator itself is very simple...The regulator is much harder to understand. But that is only because you are using more interacting coils in the regulator. The basic EE is still simple, though, for each individual coil.

 

[TR3driver]

I doubt the copper stuff is the problem, since it was working normally with the field disconnected. If the problem is on the armature side, it has to be a high resistance rather than a path to ground.

My experience has been that not many parts from the later generator will fit the early one. To get the higher current rating, they made the armature and housing just a bit bigger, so they and the front plate don't match the earlier unit. Then they "improved" the way the field connects through the rear plate, so that doesn't match either. I don't recall the issue with the field coils, but they didn't fit as-is either.

 

[sp53]

So, I take my impact gun and spin both generators; the lug one goes to 14v nice and smooth and so does the spade terminal. Then I get thinking about this so called “liquid copper” I got 35 years ago and think what if it is non- conducting? I take my ohm meter and put it inside the container shaped like a Vaseline jar and no conduction.
He probably gave it to me put on the outside of battery posts or something. We were working for Atlantic Richfield Oil at the time and the stuff we were working was going out to sea up the coast to North Alaska. The story gets better, I took the radiator out for easy of removal of the generator. Anyways, I wanted a different radiator anyway, so maybe it is serendipitous.

Right again Randall, high resistance! Plus if it would have worked the first time, I never would have had Randall help me with my education. I must admit, I learn difficulty and have to be tricked sometimes by the cosmos or I will take the path of least resistance.

 

[sp53]

Ok Randall your best student is back. I put the generator back in and I am back to a bright ignition dash light with a 2 amp discharge running at 2000rpm, suggesting, that the copper stuff had nothing to do with anything, and I that screwed up the test.

I tried test 6 with the cardboard between the contacts and a volt meter on D and ground. I got about 5 volts with digital meter. My scale volt meter is not working, so I used the digital. The suggestion is to close the gap on the cutout points by turning the screw clockwise to increase the voltage.

It does seem to me that I am back to test #1 and I am getting that lower voltage again, like the 4 volts I had earlier with test 1, but I am uncertain to what I am testing.

mmmmm

 

[TR3driver]

Test 1 shows how much the armature generates, running with no load in just the residual magnetism field from the housing. No field current. 2 to 4 volts is considered "normal". 5 volts is good enough (probably something to do with the digital meter being able to "see" some of the noise from the generator on top of the DC signal).

Obviously, that worked; it appears that the armature, commutator, brushes and connection through the end plate are at least capable of passing voltage.

So, move on to test 2, where the output from the armature is used to power the field. The main point here is to check the field circuit; but the test also depends on the armature circuit being able to supply a couple of amps.

If that fails, there is a problem in the generator (no matter what the shop says).

 

[sp53]

I did not read far enough ahead and I am on --Test #6 (continued) on page 7 of the booklet shows a problem under the heading “D” which is a continuation of test #6 in which if the voltage is “half” I guess they mean half of 12 and that would be about what I am getting. They suggest placing a screw driver between the contacts and the voltage should rise because the points are corroded.

 

[TR3driver]

So it passed test 2 this time? You said before that it did not.

In test 6, reading D, they actually mean half of 16 volts; around 8 volts. (Or 4 volts if you were working on a 6v generator.)

 

[sp53]

Yeh I jumped up to test #6 after I took the generator off and spun it with the impact gun and it showed it was working. I jumped to test #6 because I had got that far before I double checked #2.

Anyways it looks I got it. I took some emery paper and put that through the contacts on the left, but nothing happen quickly- then like it said put a screwdriver between the points on the right side, and I guess that did it. The ignition light went out the points on the right stayed closed. It is charging at 15.00v to16.2v @ 1200rpm to 1500 rpm and at 2500rpm 16.4v, so it goes up and down with the idle some.

There is some very minor arching on the points at the left, but it seems normal.

 

[sp53]

Randall I forgot to say thanks. I never would have gotten into the whole generator idea if I did not have confidence in your skill and knowledge. I would have bought some new parts from the big 3 and thrown them at the problem. Heck I was getting close anyway because I was running out of trouble shooting steps that you provided.

Thanks steve

 

[TR3driver]

Ok, well, glad it's working. But I feel I should point out they meant to short the regulator contacts, which are on the left. Shorting the cutout contacts on the right can cause problems.

Let's hope it continues to work after you've shut down and restarted.

 

[sp53]

Luckily it did keep working. So anyway the points on the left facing the regulator should be set 0.012 to 0.020? I do not think there is any gap.

 

[TR3driver]

For that, I'd suggest following the directions on the next page, which says .015" if the little copper piece is round, or .021" if it's square. ISTR most of mine have been square, but that doesn't mean much. The same information can be found in the TR4 workshop manual.

Remember that gap is between the armature (the flat plate that moves, item 6 below) and the pole piece of the relay (item 7). The contacts are normally closed.