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TR2/3/3A TR3 Generator kaput

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sammyb

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I had a suspicion that the '59 TR3's generator was dead when I drove it down to my buddy's shop. He confirmed it...he went to test out the brakes, and figure out what the clicking from the front wheel was and he said "I didn't get very far."

I've never taken apart a TR generator. I wonder if it failed during the 10 year storage, or was bad before it.

Any ideas from the electrical experts?

Thanks,
Sam
 
Hopefully I can simply rebuild it. If it something simple, like a little corrosion on the brushes (or something,) that would be great. Since I've never opened one up, I don't know what might be lurking.
 
Well from what I know - which frankly ain't a lot - they are a touch complicated. If it is toast then no harm in opening it up and seeing if there is something obvious wrong.

Funny enough I got a new MGA catalog today and the page was opened to a page advertising new generators for $99 without a core charge...
 
There isn't anything complicated about the generator. A likely failure mode is corrosion of the brush springs, preventing the brushes from making contact with the surface of the commutator. I've seen that quite a bit. Your manual should have detailed instructions for disassembly and inspection, Sam.
A thorough cleaning may be all that it needs.
Go for it.
Jeff
 
[ QUOTE ]
Funny enough I got a new MGA catalog today and the page was opened to a page advertising new generators for $99 without a core charge...

[/ QUOTE ]Unfortunately, I've not heard a lot of good about the "new" ones (at least not the "Pacific Rim-sources copies). For around $90 here in the Albany, NY, area, I was able to have my Herald's original Lucas generator rebuilt. Works perfectly (as it apparently did for most of the 41 years before the rebuild) and looks as nice as it probably did when it left the Lucas factory in late 1961!

Oh, and almost forgot: check (or have checked) the voltage regulator for proper operation as well, and repair/renew as needed!
 
I believe the voltage regulator was new when the car was put away ten years ago. There were two spare regulators, and a receipt for the new one.

Since it was parked on carpet, I wonder if the generator was close enough to the ground to pick up a little moisture?

We'll have to see.
 
Generators are great. If you don’t do a lot of idling in traffic with the lights on and the fan blowing etc you should not have any problems keeping the batt up. The usual areas that cause failure are worn out brushes and with little use in humid climates, corrosion. The replacement of the brushes is not too complicated. If you have ever taken a DC motor apart, you will find a generator similar. If you have not taken a simple DC motor or starter apart, I would just take the generator down to your local alternator/starter repair shop and see if they have any body that has rebuilt one (personally, I would wait for the service and hopefully they would let you observe the rebuild). Many alternator shops like to paint the alternators and generators that they rebuild; you probably would not want that service. Hopefully, the armature most likely does not have to be turned (trued) unless you have lots and lots of miles on the car. If you don’t have an exceptional case and you can do it your self you can get a brush set for less that $15. Emory cloth will shine up the commentator. Kerosine or even gasoline will wash out the insides; don't use brake cleaner or anything that will disolve the insulation on the windings /ubbthreads/images/graemlins/lol.gif
 
[ QUOTE ]
...I've not heard a lot of good about the "new" ones (at least not the "Pacific Rim-sources copies)...

[/ QUOTE ]

They don't even look right -- crude (to my eye) casting and no mistaking them for a Lucas. Rebuild or have rebuilt is the way to go. In addition to brushes you may want to replace the rear bearing (a shop can press out/press in for you) then keep that rear bearing oiled.

But -- are you sure it is the generator? A Lucas fault manual has a very clear step-by-step dynamo test that will identify any fault and the likely cause.
 
I don't have a Lucas fault manual. Is there one online?
 
I agree that it's most likely the brushes (about $4) and/or springs (also $4). But if the armature is bad usually a commutator segment comes unglued, there are quite a few NOS lucas ones available, from internet sources. I've seen two in the past 4 or 5 months NOT sell on ebay for $27 to $35 respectively. I almost bought one just to have it on the shelf. Both from reliable sources. Field coils rarely short out. They really are easy to tear down and I would start by cleaning the commutator as recommeded earlier. Have at it and good luck.
Tom Lains
 
If you really think the generator is bad, and it's not a voltage regulator problem, then it's probably best to bring the unit to an electrical repair shop. My experience with these generators is that the armature is weak item in the system. The easiest way to check that is with a growler and a piece of hacksaw blade to find any vibration shorts. That is then followed by 100V light ground short test...commutator to armature body. The field housing test is usually just a high voltage (500V) field coil to housing short test. Since most electrical shops have this equipment for testing the components for starters, they will be able to test the generator parts.

Most often the armature fails because it gets overworked, heats up and then "throws" solder from the commutator to winding connections. If that the case, and the insulating varnish hasn't been burned off the wires, it can be re-soldered. If it threw solder, you will see the tell-tale ring of solder inside the field housing.
 
Hello Mart,

I think you are being a touch alarmist. Most generator problems are down to simple brush maintenance (adequate length, free in the brush holders just about covers it. Springs usually last for ever.) By the way do not use emery cloth on commutators but glass paper, lubricate the bearings and reassemble. A quick test is to short both field and output terminals and apply 12 volts (keep polarity as connected in the car) to body and the two connected terminals and the armature should rotate as it is now a motor.

Alec
 
[ QUOTE ]
I don't have a Lucas fault manual. Is there one online?

[/ QUOTE ]

Not that I know of, would be a good project for me (someday). Meanwhile, here's a Cliff Notes version of the Dynamo chapter:

1. Verify that the battery is in good condition.

2. Verify belt tension is okay.

3. Test the Armature -- Disconnect dynamo leads and check voltage at the D terminal (the big one) at 1500 RPM should be 1.5 - 3.0 V.

4. Test the Field -- Leave voltmeter as above and connect ammeter between D terminal and F terminal (the little one). Increase engine speed until voltage is about 12V, ammeter should read about 2 amps.

The Haynes manual offers a variation on the above -- you disconnect the leads and connect a jumper wire between D & F. At idle the dynamo should then put out about 15V. They indicate that a reading of 0 suggests the brushes are faulty, about 1V suggests the field is faulty, 4 to 6V suggests the armature is faulty.
 
Hey Sammy - I sent you a pdf of the Lucas Generator and Control Box testing guide to your apex strategy account.

if anyone else wants a copy I'll send it along. it's about 825k. Just send me an email to jsneddon@gmail.com and I'll forward you a copy.
 
Hi Sammy, yes go for it; it is easy. One thing I am confused about is. Did the generator light come on (or was on) when it happened and is this in anyway connected to the clicking noise you heard?
Sp53
 
Sammy, I just had mine apart yesterday to clean and paint it.
Really fairly simple, just undo the two long slot-headed bolts and remove the top. The brushes are carbon, so cannot corode, but get stuck in their holders. The springs on mine were rusted but seemed to work ok after I freed up the brushes.
I cleaned out quite a bit of carbon but could not get it all without risk of damaging insulation on some of the wires inside, which was brittle with age.
Since mine had been working fine I just oiled the bearing and put it back together.
Simon.
 
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