Generator no-charge update

[Jeff/Illinois]

In an earlier thread I posted about a weird problem I was having with the Roadster. So as not to be buried I opened a new thread with what I have found so far.

One generator from a major parts house, was working OK for maybe 2 hours of use then ammeter started bouncing all over the place and would not show a charge anymore. Headlites 'on' with engine running at fast idle, shut off engine lites did not dim stayed the same. Checked voltage at generator post there was none. Cutout original, shows 49 Ohms it is good. In the meantime I had tried a known good ammeter it was the same, no charge.

Took this generator to a local rebuilder that does a lot of antique tractors, he put it on his tester and voila, something definitely wrong with it he got nothing out of it either. Good. I'm on the right track.

Fully charged battery, Voltage at battery 6.6. Voltage at starter switch 6.6 Voltage at terminal box both studs 6.5. Voltage at ammeter posts both sides one at a time 6.5 Voltage at cutout relay output side 6.5. OK looking good to me so far.

Put another generator on the car that an antique tractor builder tested for me, was putting out 7.2 Volts, known good generator here we go. Put it on the car, couldn't get a voltage reading out of the generator post. Ran car at fast idle with headlites on, turned off motor no dimming at all no change in headlites. No increase in voltage at cutout 'out' connection with motor running. Measured cutout mounting screws as someone suggested they are 1/4th inch as they are supposed to be. Used the original good cutout showing 49 Ohms of resistance.

Walking away from it for a while, it doesn't make any sense what is going on. If I find the problem I will pass on what happened. I've never seen this before

[Art Newland]

How's your ground from the engine to generator and engine to frame?

[Patrick L.]

Just for the heck of it have you tried to see if the generator will motor ?

[cpf240]

Just measuring the resistance of the coil in the cutout does not mean the cutout is good. The contacts could be dirty and not making a good connection.

[wmws]

Put a jumper wire across the cut out and test again.

[Tom Wesenberg]

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I'm sure I know the problem. The cutout isn't closing before 7.2 volts is reached. A lot of cutouts won't close before 8 or more volts is reached because without a voltage regulator the generator will produce up to 40 volts, so the makers don't care so much about voltage. I always make sure they are adjusted to close at 6.0 to 6.2 volts.

If you send the cutout to me I can adjust it for the correct voltage.

[Jeff/Illinois]

Thanks for the replies... I got called away this afternoon on another situation.

I bypassed the cutout, with the a jumper wire to energize the cutout a couple days ago, that didn't change anything.

Grounds are good and clean and tight. Thought of that also. Interesting about motoring the generator I will give that a whirl too out of curiousity.

Will report back with my findings.

Tom I'll be in touch thanks.

[Tom Wesenberg]

If you want to break the spot welds and adjust the cutout yourself, I'll list a couple threads that should help. Here's the first one.

https://www.fordbarn.com/forum/showt...air+tom&page=2

Here's another thread.

https://www.fordbarn.com/forum/showt...er+removal+tom

[Mike V. Florida]

Keep in mind that if the cutout never closes, the generator will climb in voltage until the armature fails. It may already be too late for this generator. The battery is the regulator in the stock Model A setup. Ground connections, cut out, and battery condition all play a role in the generator output.

[Tom Wesenberg]

Originally Posted by Mike V. Florida

Keep in mind that if the cutout never closes, the generator will climb in voltage until the armature fails. It may already be too late for this generator. The battery is the regulator in the stock Model A setup. Ground connections, cut out, and battery condition all play a role in the generator output.

Jeff has my EVR to regulate the output to about 7.2 volts, so he's safe as far as burning up the generator.

[redmodelt]

So how many Amps is it putting out and what is the 3 brush set for?

[Tom Wesenberg]

Originally Posted by redmodelt

So how many Amps is it putting out and what is the 3 brush set for?

The ammeter reads only the charge going into the battery, or the current being drained from the battery. Since Jeff's generator is now regulated, it has no third brush to adjust. The amps will change automatically as the battery needs more or less charge. I've had my EVR in my 28 for almost 20 years now, and after a few minutes of running, the ammeter will read just a hair above the 0 mark.

[eagle]

You didn't give us a voltage reading on the generator side of the cutout. Check it with motor running at a fast idle.

[BILL WILLIAMSON]

Have you POLARIZED it?
Bill W.

[Jeff/Illinois]

Yes, I did polarize it Bill, good point.

Voltage reading on the generator from one of the big parts houses was 1.0V if I recall correctly.

Maybe I should hook up seven of these generators to get 7V Think there is room for that many in the car?? It'll take one heck of a long generator belt!

Will be back in garage later will report back in. Thank you to all who had suggestions.

[Jeff/Illinois]

Here's an update on this bad boy.

Known good generator (Tom's) back on car.
Fully charged battery, car not running:
6.8V at cutout output side

Car at fast idle:
7.2V at generator post
1.1V-3.8V bouncing all over at cutout output post w/ wire connections
(yellow wire/yellow with black tracer)

I got a message from Tom, he said the cutout gap needs adjusted it's not able to connect. Original cutout has 49 Ohms resistance I thought it was OK. Learning as I go thanks to Tom and FB!

So, gotta be the cutout. To run the Diode Cutout Tom told me to snip the little green wire coming out of his EVR. Decided that I didn't want to booger that up like I'm prone to do so I have been trying original cutout and a 70's repop
that I had. After get the cutout back will report back in.....Tom, I'll send it your way I misplaced your phone number!! And that number was registering 7.2V when I checked it

Thanks fellows............

[HoarseWhisperer]

"To run the Diode Cutout Tom told me to snip the little green wire coming out of his EVR."

Hey, Jeff. Are you sure about snipping the Green wire for the diode? The instruction sheet I have from Tom says; " If you are using a Diode cutout, be sure to cut the BLUE wire. Separate ends about 1/16"."

[Jeff/Illinois]

Originally Posted by HoarseWhisperer

"To run the Diode Cutout Tom told me to snip the little green wire coming out of his EVR."

Hey, Jeff. Are you sure about snipping the Green wire for the diode? The instruction sheet I have from Tom says; " If you are using a Diode cutout, be sure to cut the BLUE wire. Separate ends about 1/16"."

Whoa you're right I must be color blind... good thing I 'let it be' the Beatlles knew what they were singing about Mother Mary thanks for HoarseWHISPERING words of wisdom here I highly appreciate that!

[HoarseWhisperer]

Good thing neither of us are trying to defuse a bomb by cutting wires.

[Jeff/Illinois]

Originally Posted by HoarseWhisperer

Good thing neither of us are trying to defuse a bomb by cutting wires.

You be right Glenn!!