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Ammeter - this is crazy?

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tomster Avatar
tomster Tom Dunbar
Annapolis, Maryland, USA   USA
Current status on this is I re-ran the Lucas test with my engineer neighbor and we came up with the .25 volts reading.
We also tested for continuity the wire from the 'D' terminal generator to the Regulator and that checked out OK.
Tomorrow I will do the test from the Moss video to check the voltage output from the generator.
I'm expecting a zero to super low volts reading on this.

Basically, I think I just need a new generator. I also did the polarization as well and it did not help.
Might do the full field test as well for good measure.

Thanks all for your help!



Edited 1 time(s). Last edit at 2017-11-11 06:20 PM by tomster.

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oldhokie Gold Member DAN ALLEN
Myersville, Maryland, USA   USA
In reply to # 1497416 by tomster Current status on this is I re-ran the Lucas test with my engineer neighbor and we came up with the .25 volts reading.
We also tested for continuity the wire from the 'D' terminal generator to the Regulator and that checked out OK.
Tomorrow I will do the test from the Moss video to check the voltage output from the generator.
I'm expecting a zero to super low volts reading on this.

Basically, I think I just need a new generator. I also did the polarization as well and it did not help.
Might do the full field test as well for good measure.

Thanks all for your help!

If you decide to do a full field test please note the instructions I provided in my earlier response are wrong. I spoke before fully engaging brain confused smiley The test procedure is the same for either battery polarity. It differs for A-circuit and B-circuit output regulation and I don't know which wiring is used on those generators/regulators.

  1. A-circuit wiring excites output by grounding the field contact
  2. B-circuit wiring excites output by connecting the battery (ungrounded terminal regardless of battery polarity) to the field contact

From the Holden video I watched it sounded like B-circuit but that's not 100% clear

My apologies for the misinformation,

UPDATE: After doing a bit more research charging diagram in TR4 shop manual shows Lucas C40 and C40T generator field is internally grounded (e.g. B circuit) Interestingly that generator was also used on 60's era Ford tractors cool smiley

To full field the C40/C40T generator start engine and set revs at 1500+ (2000 probably a better choice). Then BRIEFLY jumper the ungrounded battery terminal to field terminal on generator end plate. Ammeter should show solid charge. Do not operate generator in full field condition for more than a few seconds - just long enough to check the ammeter. Alternatively you can also check output with a voltmeter across the battery. When full fielded the voltage should jump to about 15-16 VDC.. You should also have battery voltage from armature terminal on end plate to ground. If you don't the cutout in the control box or it's connective wiring is likely defective.

HTH

Dan



Edited 3 time(s). Last edit at 2017-11-12 07:19 PM by oldhokie.


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James E Avatar
James E Silver Member Jimmy Campbell
Bedford, Va, USA   USA
When I was trying to figure what was going on with me gen. I followed all the Lucas testing procedures and at one point at 3k rpm my gen. was putting out 46 volts, this was with out the regulator. Ended up I needed to clean all of my contact points. All good now.

tomster Avatar
tomster Tom Dunbar
Annapolis, Maryland, USA   USA
I ordered and received a new generator from Victoria British. I'm planning on putting it in tomorrow but am wondering
if I should test the voltage regulator (control box) as well? I've been watching video's on these and might do some
maintenance on it but also I like adhering to the adage 'If it ain't broke, don't fix it'. So perhaps to keep it simple if I
replace the generator, wire it all up and take the car for a test ride, would observing the Ammeter be enough to tell if
everything is good?

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
I would still run through the tests. Among other things, there is a good chance that the control box caused the generator to fail.

Armatures (commutator mostly) do wear out, but in my experience the most common failure mode is overheating caused by a misadjusted control box.
Back in the day, some .mechanics would insist on replacing both at the same time, because of the chance that one was causing the other to fail.

Also, this system is pretty marginal to begin with. If it is not working at top form, you are likely going to have problems down the road.

I also have a healthy distrust of new (and rebuilt) components. Or maybe "trust but verify" is a better way to put it smiling smiley

Don't forget to repolarize before starting the engine. If the manufacturer (or rebuilder) tested it with the opposite polarity, there is a chance that the cutout contacts can be damaged when they close with 24 volts across them.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

oldhokie Gold Member DAN ALLEN
Myersville, Maryland, USA   USA
In reply to # 1498574 by tomster I ordered and received a new generator from Victoria British. I'm planning on putting it in tomorrow but am wondering
if I should test the voltage regulator (control box) as well? I've been watching video's on these and might do some
maintenance on it but also I like adhering to the adage 'If it ain't broke, don't fix it'. So perhaps to keep it simple if I
replace the generator, wire it all up and take the car for a test ride, would observing the Ammeter be enough to tell if
everything is good?

"If it's not broken keep fixing it until it is" spinning smiley sticking its tongue out

IMO the simplest and most reliable test of the charging system you can do is to install the new generator and measure the charging voltage with everything in the system.
If it's charging at the correct voltage when the battery is under voltage and it cuts out when the battery is up to full charge it's working properly. If it's not doing that then move on to unit testing.

Dan



Edited 1 time(s). Last edit at 2017-11-18 09:14 AM by oldhokie.


Member Services:
Engineering, design and fabrication of custom. hard to find, or NLA parts and tools. No job too small.
tomster Avatar
tomster Tom Dunbar
Annapolis, Maryland, USA   USA
Before I install the new generator I want to make sure my control box is ok. I’ve been reading up on it in the shop manual and I have a stupid question. For the cut-out voltage testing it clearly indicates where to connect the voltmeter for a reading (D and E terminals), but what about the regulator? I’m not certain where to measure from?

One other question. For the gap setting on the regulator the manual indicates there is either a square or round copper separator which determines the gap. I’m not sure how to tell without taking everything apart. Not readily visible.

Thanks!


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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Same connection, D to E. Note that, while setting the voltage, it is important to either block the cutout contacts, or remove A and A1 and connect them together. Otherwise, the voltage adjustment will be affected by current going to the battery and ignition. I usually tear a piece of ordinary printer paper into a U shape, so it will slip into the cutout easily and stay in position.

Mine have all had the square copper piece; but I wouldn't take that as a guarantee that they all do. It's easier to see when you have the upper contact out for cleaning (which I definitely recommend before adjustment), but you should be able to make it out by peering in from the side. Might need a loupe (I know I do) and perhaps a source of light.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

tomster Avatar
tomster Tom Dunbar
Annapolis, Maryland, USA   USA
Current status is I ordered a new generator, fan & pulley (as I couldn't get the old fan/pulley off the existing generator).
Anyway, now I'm attempting to put the pulley on and it is not sliding over the woodruff key easily. My question is - should
this just slip on or does it need a few whacks with a rubber mallet? I can see a slight jagged edge on the pulley and I just
don't want to screw it up at this stage. Perhaps I should file this down? Photo attached.

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tomster Avatar
tomster Tom Dunbar
Annapolis, Maryland, USA   USA
Forget my prior post. I filed it down.

tomster Avatar
tomster Tom Dunbar
Annapolis, Maryland, USA   USA
Ok - but seriously, how hard is it to put a pulley on a generator? Pound it on with a rubber mallet standard?

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
They vary a lot; often it will just slip on. But that's for old units that have been together and back apart many times; likely a new one would take some encouragement.

I know there have been lots of complaints of the key and slots not being quite the right size on new water pump pulleys and pumps. Appears that some manufacturers are trying to substitute metric size keys instead of the original inch sizes. Could something similar be the problem with your new generator?



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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