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Old 08-03-2021, 04:53 AM   #1
Bruce of MN
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Default Flashing Generator

On a recent hot day, my car stopped running, but was able to limp home. I thought it was a combo of vapor lock and low gas level in the tank. The low gas didn't help, but it turned out that the wire (possibly original) from the starter to the terminal box had broken at the flag ring terminal at the box. Wasted time switching to my spare gen and as a diagnostic step, I tried motoring the gen. It did fine, then I discovered the broken connection and fixed it. It had showed continuity from the cutout output terminal to the other side of the ammeter, but the broken wire must have made occasional contact when not being bounced away by vibration or road bouncing. When I started the engine, all was fine again.

I think that with both generators that the broken wire made intermittent connections and messed up the field polarity and the motoring I did flashed it and restored proper polarity. Luckily, all it cost me was a new ammeter from Bet's, which isn't the worst thing in the world. Next time, I'll know that it the gen is showing no output to try flashing it.
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Old 08-03-2021, 08:07 AM   #2
Badpuppy
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Default Re: Flashing Generator

Be careful what you're interpreting. The ammeter indicates battery charge, not generator output. Generators should not require polarization if run every few months.

You located and repaired the problem, all is well.
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Old 08-03-2021, 09:16 AM   #3
rotorwrench
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Default Re: Flashing Generator

I'm not sure the ammeter knows the difference. It indicates both output and charge rate since they are related. Now if the bus wire is disconnected, the ammeter should indicate that during the start phase since it won't show discharge change when the points open and close. Intermittent connections can be difficult to identify. I figure there is a reason that Ford made the terminal box easy to open.

I learned the hard way that checking the wiring for condition and security should be done on a regular basis. In my case, the terminal box was melted (cheap repro) and wiring was damaged. I also installed a fuse.

Last edited by rotorwrench; 08-03-2021 at 10:55 AM.
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Old 08-03-2021, 10:52 AM   #4
Bruce of MN
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Default Re: Flashing Generator

My thoughts were that if the ammeter didn't swing to the plus side when I rev up the engine, the generator isn't working or there is an open circuit somewhere.
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Old 08-03-2021, 04:18 PM   #5
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Default Re: Flashing Generator

Quote:
Originally Posted by Badpuppy View Post
Be careful what you're interpreting. The ammeter indicates battery charge, not generator output. Generators should not require polarization if run every few months.

You located and repaired the problem, all is well.
Without generator output there will be no battery charge.
Bill
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Old 08-04-2021, 08:21 AM   #6
Badpuppy
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With generator output there will be no battery charge if the circuit is open, which was the case. What I meant is with no current indicated, you can't assume no generator output.
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Old 08-04-2021, 01:53 PM   #7
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Default Re: Flashing Generator

Quote:
Originally Posted by Badpuppy View Post
With generator output there will be no battery charge if the circuit is open, which was the case. What I meant is with no current indicated, you can't assume no generator output.
The ammeter indicates current flow only, not battery charge. If the battery is defective it may not accept a charge but the ammeter will still show a charge.
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