Generator not working, advice please

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Model T Ford Forum: Forum 2015: Generator not working, advice please
Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, September 21, 2015 - 09:38 pm:

My 6v 1926 has a generator that hasn't worked since I've owned it. I have just been charging it manually every so often.
Here is the tests I completed -

1. The amm meter is an after market which reads not working. (I have a period one to fit after I get this sorted).
2. Lights don't flare up when revved above idle
3. Analog volt meter reads zero from either side of the regulator connectors at fast idle
4. Analog volt meter when applied to the battery terminals on the car shows nothing different with engine running & revving.

Am I missing something obvious here?

Also I have two spare Genny's, one removed from my 27 because it was 6v (this unit wasn't working using the same tests) and another in my spare parts box (no history known).
I have read that putting power to the connections when on the bench the Genny will run like a motor. I tried putting 6v from a battery charger on both of these Genny's and both reacted the same.
A slow movement with a groan when 6v applied to the left terminal & earthed and nothing at all when applied to the right hand terminal.
Does this mean these two bench tested spares are faulty?

Thanks


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Monday, September 21, 2015 - 11:29 pm:

From your initial tests, it does indicate no charge. Battery voltage should rise slightly at normal engine speed.

Your mention of a regulator, and what sounds like an extra terminal makes me think the generator has been modified. A not uncommon mod is to bring the field winding connection to an extra terminal mounted on the generator so it can be used with an external electromechanical voltage regulator of the Bosch or Lucas type.
The standard Model T generator has only one terminal, and works with no voltage regulator. A go/no go bench test is to simply connect a 6 or 12V battery between this terminal and earth and see that runs as a motor. A battery charger might not have enough current capacity for this test.

It sounds like we might need to see some photos because testing them will be different if they've been modified.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, September 22, 2015 - 12:40 am:

John thanks for your comments. Sorry i should have said cutout not regulator, so that's standard.
I've just tested the 2 units out of the car using a 12v battery and your correct the battery charger didn't have enough grunt. They both spin well but only on the left connection so I guess both cutouts are stuffed.
I do have a new cutout in stock.
Can you suggest a method I test the Genny in the car in place plus the wiring etc to ensure its safe to fit the new cutout without risk?
Ta


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, September 22, 2015 - 01:52 am:

Thanks Kevin for clarifying things. Now I understand - you've got the the standard cutout and it's on the generator when testing.
In that case, the results are as they should be.
What you call the left connection would be the actual generator terminal, so yes when you put 12V into there it spins. The right terminal would then be the battery terminal of the cutout. You certainly don't want it to spin when you put 12V there. If it did, it would mean the cutout has shorted contacts or is otherwise stuffed.
So far so good...
What I would try next is a few tests in car.
1) On the battery terminal of the cutout (right side terminal when standing next to the car), you should see full battery voltage at all times, whether or not the engine is running. If not, there is a break in the wiring between here and the battery.
2) With the engine running at a fast idle, you should be able to measure voltage at the generator terminal (the left side terminal). It should be equal to, or greater than the battery voltage.
3) If the generator voltage is lower than the battery, try flashing the generator. That is, touch a wire between the two cutout terminals for a couple of seconds (never do this with a Fun Projects voltage regulator by the way). If the voltage now comes up, all should be good and that's all it needed.
4) If the voltage at the generator terminal is higher than the battery voltage then the cutout is open circuit and defective. Avoid running the generator like this because it means it's running on no load and could damage the field winding.

Another simple test is to connect a test lamp between the two cutout terminals. With the engine off, it should glow, indicating that the wiring from the battery is OK and the generator is internally probably OK. When you start the engine and rev it, the lamp should go out assuming the cutout closes - which it will if the generator is working. At that point, the ammeter should show a charge.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, September 22, 2015 - 03:19 am:

That's great John, brilliant description. I'm about to head out to do the tests.
Unfortunately one of my spares was disconnected in my other car when i purchased it for about a thousand miles and the one in this car has had the wire off for a couple of months.
Anyway I'll go check....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, September 22, 2015 - 04:45 am:

1. No reading on the batt side (right) so a break in the loom needs addressed.
I have a wire under the seat connected to battery terminals for manual charging so I extended the positive lead to the batt side of the cutout. Now I can carry on testing -

Batt side of cutout voltage read 6.4v

2. Engine running fast idle and gen terminal (left) read zero volts.
So I Flashed the Genny with no improvement.

I then removed the cut out and fitted one of the 2nd hand ones of an other Genny.
Still nothing on the left side so flashed this cutout and eureka!
At fast idle 8.o v on the batt side. The battery is slightly down and in need of a charge up.
Measured voltage on the Batt side from slow idle to fast idle and it moved from 6.8v to 8.0 v. Sounds good to me as it increases with the revs and I realize the battery is a bit flat but the 8.0 v output may be too high? I wonder if this will reduce once the battery is fully charged?

I ran the car for about 5 mins then turned off. Battery output has increased from 6.4 v to 6.9 v with motor off so it must have been charging.
My usual test of the years is lights on at slow idle and watch them glow brighter as i rev. There is no increase in the glow? Is this because I have bypassed the amm meter/dash wiring loom etc

I have a new terminal block and dash loom and correct amm meter to install so maybe this might address my concerns but I wont do this until I know its charging correctly.
Your thoughts?


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, September 22, 2015 - 06:45 am:

Sounds like it's now working! It could be the original cutout had an internal short to earth on the generator terminal - quite possible if it's an original with old crumbly insulation.
8V on the battery side of the cutout is not all that surprising. The voltage here will be slightly higher than the voltage right at the battery terminals, because of the wiring resistance between the cutout and battery terminal. The amount of voltage increase will be dependent on the current flowing. The effect will be more noticeable the higher the charge current and if the wire is too thin, has poor connections along the way, etc.

As to using headlight brilliance to see if it's charging, it really depends where along the wiring the headlights take their feed from as to how much it will show up. The effect will be more obvious if the headlight feed is closer to the generator than the battery because the voltage rise will be greater here when the generator starts charging. It's a rough and ready test, but not always reliable.

Most importantly, you've tracked down the fault, so next step is to install the ammeter, terminal block and wiring loom, and see what the charge current is. For an unregulated setup (cutout only), it's best not to exceed 5A for a 6V system.

(Message edited by 26tourer on September 22, 2015)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Tuesday, September 22, 2015 - 08:07 am:

If you have not already done so, It would be a good idea to clean up the armature with a little sand paper and a wash with some electrical contact cleaner. My generator would only charge after it was flashed each time when started but after cleaning up the armature it picks right up on its own and was putting out so much that I had to back off the third brush.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, September 22, 2015 - 05:48 pm:

Thanks John that sounds good news. Bit of luck my manual charging days could be over soon.

Is there a right or wrong way to connect up the loom especially around the amm meter as the current system is home made?

Val, good point. I will check again today and see if it requires another flash. I might take it out and clean it up, not sure if RHD cars allow a simple slide off or whether the carby needs to come off first.

Whats involved in adjusting this 3rd bush if I need to go there?

Thanks


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, September 22, 2015 - 07:14 pm:

I'd recommend keeping to the original Ford circuit for ease of future fault finding:
wiring
Basically, the ammeter is in series with everything (except the starter) that connects to the battery.
This way it shows both charge from the generator and any discharge from the accessories.
The polarity usually isn't marked on the back of the ammeter, so if it shows "charge" instead of "discharge" when the lights are on, it just means you need to reverse its connections.

For adjusting the 3rd brush, be careful because the insulating strip on which it is mounted can crumble away and short out the 3rd brush. If that happens it stops charging. There is a repro fibreglass replacement insulator available if you need it.
To adjust the current, simply loosen the 3rd brush nut with a small spanner (I can't remember the size), have the engine running at fast idle, and slide it one way or the other until you get the required charge current.
I don't think I've had to take the carby off to get the generator out, but it does require a bit of dexterity because of the steering column.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Tuesday, September 22, 2015 - 08:01 pm:

Kevin, the third brush is adjustable by moving it closer or further from the armature. There is a lock nut that holds it in place that you can loosen and then adjust the brush holder. There is a wrench that is designed to make it easier but it can be done with a standard open end wrench. I forget the size.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, September 22, 2015 - 08:38 pm:

I done a test run and it's working fine again today so maybe it will be fine without 3rd brush adjustment.
Thanks for the drawing John.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Wednesday, September 23, 2015 - 01:43 am:

Just fitted the new dash wiring loom, didn't change the amp meter as the previous owner had cut too much out of the face plate. Found the break in the feed wire, Genny to terminal block. Fired it up and all good including the after market amp meter going.
Had it running for 5 mins, still charging 15 on the meter and putting out 8v at Genny & 7.5v on the battery. Will take for a drive soon as it will be dark and see how it handles that.
Thanks a heap for your advice guys.


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Wednesday, September 23, 2015 - 02:02 am:

I'm pleased it all worked out. However, 15A is way too high. Left too long it will boil the battery and shorten the life of the generator, although you'll just get away with it for short infrequent trips.
The 3rd brush really needs to be adjusted for the long term.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Wednesday, September 23, 2015 - 03:46 am:

Yes John I agree. I charged the battery manually for an hour to be sure after a drive and then done another check, still running 15A plus the Genny is putting out 9v at fast idle & 8.5v on the battery. I need to wind this back or as you stated the battery could boil.
I will have a go at the third bush tomorrow.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, September 24, 2015 - 04:29 am:

Was still charging too much so I made a few adjustments, I have a fuse near the Genny and it blew this twice as I adjusted the third bush. Then it stopped working. So I removed the Genny (Right hand drive T's suck). Cleaned up a spare and fitted.
This one charges but not by a lot, maybe 2 amps and it drops to just under zero at slow idle. Looks like it is set to maintain the battery for day running so should be ideal. Will give it some test running and decide if I need to adjust it up.
Thanks Guys


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Thursday, September 24, 2015 - 06:32 am:

Your battery will appreciate the 2A charge rate.
You'll probably get away with it for normal day driving.
I wonder if the 3rd brush insulator has failed in the original?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, September 24, 2015 - 07:18 pm:

Not sure why it stopped John.
The one I fitted from my spares I had no history for, it was very oily inside & out, I wasn't game to pull it apart so I removed the end cover, sat it in a bowl of turps and held the drill on the end and spun a heap of oil out. Rinsed a few times then blew it out and then fitted to the car.
What I did notice besides the low output is tracking near the brushes.
You can view the attached a link - https://www.youtube.com/watch?v=nw8ePrCnucg&feature=youtu.be

Is this normal or perhaps a result of the oil or my rinsing?
I plan to run it a bit and see if the output fluctuates before I consider a slight adjustment.


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Thursday, September 24, 2015 - 07:31 pm:

That's a new way to clean out a generator I never thought of :-)
I've seen that kind of tracking when new brushes are installed and they haven't yet bedded in but it clears up after a while of running.
Obviously that won't be the situation here, but it could be remaining dirt in or on the commutator. You could try cleaning it by holding a piece of 600 grade sandpaper against the commutator with it spinning. Also scrape in between the segments to get any carbon out.
Otherwise, like you say, run it for a while and see how it goes.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stephen D Heatherly on Thursday, September 24, 2015 - 07:53 pm:

I know what the problem is! Your steering column is on the wrong side of the car. :-)

Stephen


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, September 24, 2015 - 09:06 pm:

Exactly Stephen! When I was swearing away trying to remove the Genny I was thinking the same, and I thought I could hear the Coupe chuckling at me lol.


Will try that John. What I notice today is a noise perhaps from the Genny drive cog. It only starts when the spark is fully retarded.
Here is a pic of my wash plus I bent up a spanner to reach the adjuster...perfect!
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