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Lucas Generator

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TexasKnucklehead

Jedi Knight
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More than a year ago, I assembled a generator from the best bits from several others and tested it by turning it with a motor on the bench -it produced well over 12volts as I recall.

I finally tried to hook-up the charging circuit on my running chassis, and it won't put out anything. Using the LUCAS "Generator and Control Box Tests", I still can't figure out what is wrong. I was a little confused during wiring as to what terminal on the generator was F or D and had it wired wrong for a couple minutes -I hope I didn't kill it.

(Generator testing) TEST one says to unplug the generator and use a volt meter to D, expecting 2-4 volts at 3k RPMs. I get about 1v at idle and almost 3v at 3k RPMs.

TEST two same as above but F and D linked on generator, expecting voltage to rise with RPMs. I get 0v at any RPM -which is supposed to indicate a grounded field coil or connection. But, I can measure 6.3ohms from F to Gnd. I've made sure the long screws are insulated.

What am I missing? I have been thinking about converting to an alternator when the generator gave me trouble, but I didn't expect it to be before the car was driven for the first time.

I thought getting the charging circuit checked out would be a quick, easy, feel good, thing to do while I'm waiting on body parts that I don't want to put on. I'm not complaining, because now I know that all the obvious water leaks and oil drips have been fixed and the engine is starting up and sounding happy.

Jer
 
Best I can think of is an intermittent short somewhere. Can you retry test 2 using an ammeter to connect the armature to the field? Do you have the insulating sleeves and washers all in place on the armature (D) and field (F) connections?

Another possibility might be a high resistance connection somewhere in the armature circuit. What do you get if you try to measure resistance from D to the case (not turning) ?
 
TR3driver said:
Can you retry test 2 using an ammeter to connect the armature to the field?
Click to expand...
The only ammeter I have is the dash unit. It shows no current, but still no voltage. (Maybe I can't see the small amount of current on the meter?)

TR3driver said:
Do you have the insulating sleeves and washers all in place on the armature (D) and field (F) connections?
Click to expand...
Yes. And verified with an ohm meter.

TR3driver said:
Another possibility might be a high resistance connection somewhere in the armature circuit. What do you get if you try to measure resistance from D to the case (not turning) ?
Click to expand...
If I pull the brush (on the bench), it's open. But installed, it measures around 20 ohms, but varies to much less if the belt is moved, causing the armature to move -it depends on where the generator stops.

When/If I polarize for negative ground, I get a good spark each time, and if I hold the lead powered for a minute or two, the lead doesn't get hot and the battery voltage doesn't drop considerably, so I don't think I see a major short anywhere.
 
Tex-

Not to pull you over to the dark side, but if you need more spare genny bits, hop over to my place as I'm tripping over several units. I'm still planning on using an alternator so I have more than I need!

Randy
 
20 ohms is way too high, that won't work at all. Should be down under 1 ohm, no matter where the armature is positioned. Weak brush spring, brush binding in it's holder, oil on the commutator, brush wire loose, etc.

If the high resistance positions are always in the same place, it might be some open windings/commutator segments, but I'd look at the brushes first.
 
Correct -20 ohms is too much. Thanks again Randall.

After cleaning the commutator with a very fine abrasive soaked in gas, giving each of the brushes a couple wipes with emery cloth until the curve was gone (so they have to re-bed, but I'm sure they are clean) and putting an extra turn on the brush springs (showing a measurement on my scale around 30oz) the resistance is about 6 ohms, no matter what position it is rotated.

Now with the ammeter used to tie the F and D, I'm seeing 50 volts at 3K RPMs, and barely an indication of current on the ammeter (the needle moves, but not much).

For now, I'm thinking the alternator upgrade can wait for another day.

Thanks again.
 
TexasKnucklehead said:
I'm seeing 50 volts at 3K RPMs,
Click to expand...
Egad! Note that the book warns not to let it exceed 20 volts, for fear of damaging the insulation (or overheating the field coils).
 
Texas - am in the same situation with my GT6 and wondered how the rest of the work went.

My past two months so far:

Ignition light on the dash would not go out.

Started tracing the problem but was not able to make a lot of sense and the readings were not passing Test # 1, so ended up with some expenses on the way.

Shop #1 - paid $30 to be told that everything was wrong with the genny and I should get a new one.

Shop #2 - paid $100 for a genny overhaul. It came back cleaner and with new brushes. NO change in the results from Test 1 and 2 as described above.

Vendor # 1 - paid $ 150 for a reman genny and a new control box.

Have now got past Test # 1 - # 4 (and as a note I got to 65 volts on Test # 2, and yes I know I was not supposed to get that high).

So from the Lucas book I am pretty confident that the genny and the wiring from the genny to the control box are good.

But still I can't get the output from the control box to shut off the ignition light.

Would be interested as to how the rest of your experiences went.

jb
 
ArcticOne said:
Have now got past Test # 1 - # 4 (and as a note I got to 65 volts on Test # 2, and yes I know I was not supposed to get that high).
Click to expand...
So now you will be doing tests 5-10 in Part 4, no? (Correct me if I'm wrong, but I think a GT6 should have a RB340 control box.)

If you connect the generator wires to the control box, and run the engine at a fast idle, what voltage do you measure from terminal D to ground (E)? Between terminal F and D ?

Also, just to be safe, check for any voltage between D and WL (they should be connected together inside the box so no voltage).

Yes, I know you just bought a new control box, but it seems that new ones are frequently defective or improperly adjusted or have oily contacts.

Another possibility is that the dash light is not wired properly. If you find ~12v on terminal D & WL and the light is still on, then it's not wired correctly.
 
Yes, Tests 5- 10 in Part 4 (if I can figure out what they are talking about). And yes to the RB340.

Only testing on the control box so far is measuring gaps (they were off) and checked voltage between B + E - obtained battery voltage which is a sign that the Earth wiring is OK.

Remainder of the tests will be done this week and in to the weekend.

Car has run quite well for the past 2 years and it was only when the initial genny failed that the light stayed on, so assuming that the light wiring is ok, but as others have said, never assume ....

jb
 
I have the (more simple) RB106 regulator, but once I put the proper tension on the generator brushes, it was all down hill. I know I made some adjustments, but nothing specific comes to mind. I know it's working properly, as well as I can tell, since very little is wired up and the body is not ready to be installed.

It keeps the battery charged. If I let it idle too low, the light will turn on dim and revving makes it go out. When it's not running, and turned on, the light is on. The Prince of Darkness awaits another day.
 
tomshobby said:
I was wondering what this might fit.
Click to expand...
RB340 is the model number, there are several different part numbers depending on exact application. For example, I have PN 37344H listed for Spitfire Mk 2&3; 37343H for GT6; 37342H for TR2000 & Vitesse/Sports6. ISTR the only real difference is the value of the resistor and the adjustment, but I could be mistaken about that.

Anyway, there is a long list of cars & trucks it might fit, including Jaguar, MG, Triumph, Land Rover, etc.
 
I just noticed the "22A" sticker peeking out in your photos. An eBay auction claims the 22 amp model fits:

# Bedford HA Van 6/8cwt, Beagle Estate - 1964 to 69
# Bedford CA Van - 10/12/15 cwt (Petrol & Diesel) - 1964 to 69
# Bedford JO/TJ/TK - 1965 to 69
# Austin 1100, 1300, GT - 1963 to 71
# Austin Maxi 1500/1750/HL - 1969 to 72
# Austin 1800 - 1964 to 72
# Austin-Healey - Sprite - 1970 to 71
# Land-rover - Series IIA - 2 1/4 litre (Diesel) - 1967 to 71
# MG MGB & MGB GT - 1963 to 67
# MG Midget - 1970 to 71
# MG - 1100,1300 - 1964 to 71
# Morris - 1100,1300,1800 - 1963 to 72
# Riley Kestrel - 1100, 1300 - 1966 to 70
# Rover - 95, 110 - 1962 to 64
# Triumph - 1300, TC - 1965 to 70
# Triumph - Spitfire - 1962 to 70
# Vanden-plas - 1100, 1300 - 1964 to 72
# Wolseley - 1100, 1300 - 1966 to 72
# Wolseley - 18/85, S - 1968 to 72
# Commer - Cob, Imp van - 1965 to 71
# Commer - 1500, 2500 Van - 1966 to 67
# Commer - Walk-thru (4 and 6 cyl.) - 1961 to 67
# Commer - KAD, VA - 1962 to 67
# Commer - Karrier, Gamecock, WA, WB, WC - 1963 to 69
# Ford - Anglia 105E,1198cc - 1965 to 68
# Ford - Capri 1300, 1600, 2000, GT - 1969
# Ford - Cortina, Corsair all models - 1962 to 70
# Ford - Escort 1100, 1300, 1300GT, Twin-cam - 1968 to 72
# Ford - Zephyr 4 & 6 Mk.III - 1962 to 66
# Ford - Escort Van 6/8 cwt, - 1969 to 71
# Hillman - Avenger 1250, 1500, GT - 1970 to 72
# Hillman - Hunter 1500, 1725, GT - 1969 to 71
# Hillman - Imp, Imp sport - 1963 to 71
# Hillman - Minx, Husky - 1965 to 71
# Humber - Hawk - 1966 to 67
# Reliant - Anadol FW5, Carmel - 1966 to 69
# Singer - Chamois, Gazelle - 1965 to 70
# Sunbeam - Alpine, Rapier - 1965
# Sunbeam - Imp Sport - 1966 to 71
# Vauxhall - Viva HA, HB - 1070/1159cc - 1963 to 69
# Vauxhall - Victor FC101 - 1965 to 67
# Vauxhall - Victor FD - 1967
# Vauxhall - Velox, Cresta PB - 1965

But of course any data from eBay is suspect. I found another auction claiming it fits a TR4 (which of course it does not) :smile:
 
Randall,

I have been trying to figure out what it was doing with the parts for my '74 Midget. The only thing I could think of was that the PO just ordered everything on the page. As near as I can see he had to have ordered it at least 10 years ago.

Thanks for the list, might be able to find a home for it. Much better than just laying on a shelf.
 
Practically every collection of parts I've ever bought has had a few oddballs from other cars. For example, my TR3 project came with what I believe are Jaguar bumpers stored in the trunk. And I just gave away a box of probable MGB parts the other day, that were mixed in with some TR parts from flea-bay.
 
Did a lot more reading tonite and attempted one of many tests.

In something called The Lucas Switch I found a comment about checking the resistance between the D + F terminals at the control box. With the engine off and the D + F leads at the control box disconnected I checked the resistance and found it to be 63 ohms. The article suggested that it should be under 1 ohm. I then went and tested by old box and it too reads 63 ohms.

Some fooling around and I noticed that the resistance dropped to 0.5 ohms when I firmly closed the contacts on the voltage regulator bobbin. Being that these contacts are supposed to be normally closed I wonder if this is a big part of the problem?

Any thoughts?

I likely won't get round to any engine running tests until the weekend as the garage is tightly packed with 4 cars and room is at a premium.

jb
 
Forgot to add a comment for Tom - what are your plans for your Control Box? Do you have a use for it or looking at selling it off - I may be interested in it, altho the rear has a slightly different configuration (likely from the year when it was manufactured).

On the back there should be some numbers and letters imprinted - they are visible in your photo on the side with the two attaching legs. What numbers are they (mine are 12V-16 72 and 37568A).

jb
 
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