Stray Discharge

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Model T Ford Forum: Forum 2017: Stray Discharge
Top of pagePrevious messageNext messageBottom of page Link to this message  By John Neal on Monday, May 29, 2017 - 11:23 am:

What's going on here? Could use some troubleshooting tips for the non-EE.

When I attach the battery, the ammeter immediately goes to -20. Then, when I turn on the headlights, it pegs to the left. Disconnect the battery and it goes back to 0.

Small Print:

- 6V system - '25 Roadster
- Engine is not yet ready to run, alas.
- Rebuilt generator with an FP VR.
- All new wiring and terminal block that's been quadruple checked.
- Starter is not connected.
- Lights, horn, and coils functioning normally.

Thanks!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Monday, May 29, 2017 - 11:38 am:

The cut-out points are welded together. Scrap it before fire starts


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Monday, May 29, 2017 - 11:40 am:

"with an FP VR." Do they have point in them?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Brad Marble on Monday, May 29, 2017 - 11:40 am:

John; I would start by disconnecting the battery lead from the generator cutout or whatever you are using in place of a cutout,and reconnect the battery for a test. Something is drawing current but is not a dead short, the generator is about the only thing in the circuit that could do that. Good luck Brad.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan McEachern on Monday, May 29, 2017 - 11:40 am:

Call John Regan- seems your voltage regulator is shorted. Perhaps the polarity is incorrect and shorted the diode?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Monday, May 29, 2017 - 11:46 am:

-20 amp reading on meter would show discharge... headlights "on" needle pegs to left....also discharge ????.....not too sure on FP VR.

There is a direst wiring short somewhere,

Have battery connected as negative ground ??


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Monday, May 29, 2017 - 11:58 am:

The guys are right. Probably the cut out relay and disconnecting it is your first step. Assuming "to the left" is full discharge the ammeter is working correctly and the battery connections are right. Turning on the head lights only adds a further drain which causes the meter to peg.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Neal on Monday, May 29, 2017 - 12:10 pm:

Ah ha! Disconnected at the generator terminal and the problem went away. Removed the voltage regulator and reconnected at the generator terminal, problem returned. Diagnosis: Short in the newly rebuilt generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Monday, May 29, 2017 - 12:17 pm:

Check that relay. All you did was duplicate what happens when the points are welded together.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Neal on Monday, May 29, 2017 - 12:25 pm:

Hmmm...Charlie, what relay? Points?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Harper - Keene, NH on Monday, May 29, 2017 - 12:48 pm:

Hi John,

Your newly rebuilt generator is Likely FINE, as voltage applied directly to it will flow through the generator and will discharge the battery IF the engine is not running.

All cutouts (having points), diode cutouts, and the FP VR prevent battery voltage from flowing into the generator when the generator is not charging (engine not running).

Is your Fun Projects Voltage Regulator intended for negative ground?

Is your battery connected for negative ground?

The FP VR is polarity sensitive. It does not like (will fail) if connected to the wrong pole.

Your description of the ammeter's indication is a bit confusing. Most ammeters are labeled Discharge on the left and Charge to the right of zero. (I have seen one or two aftermarket meters labeled opposite)

Please keep us posted and good luck with your project. Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Monday, May 29, 2017 - 12:52 pm:

The cut out relay you removed. Battery in one side Gen connected to the other. If it's failed and the points inside are stuck together you get exactly the same thing by connecting the battery wire to the generator as you did. That's why it's called a cut out relay. It disconnects the Gen from the battery when the engines not running. You have a bad relay not a bad generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Monday, May 29, 2017 - 12:55 pm:

You don't have a cutout if you have the fun projects voltage regulator. When you attach the battery directly to the generator it tries to act as a motor and will draw current. Your generator is likely ok. You need to call John Regan.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Neal on Monday, May 29, 2017 - 01:08 pm:

Thanks, Bill. Yes, all 6V negative ground. Yes, left is discharge on the ammeter. Suggestions to confirm the voltage regulator is bad and not the generator?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Burger in Spokane on Monday, May 29, 2017 - 01:37 pm:

How much air pressure in the tires ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Brad Marble on Monday, May 29, 2017 - 01:50 pm:

John; Your generator is ok, the device you are using in place of a cutout is shorted and trying to run the generator as a motor, the diode cutouts seem to work very well. Brad.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Eckensviller - Thunder Bay, ON on Monday, May 29, 2017 - 01:58 pm:

From the Fun Projects regulator instructions:

"The Ammeter should not show any charge or discharge after the battery wire is connected. Any reading on the Ammeter indicates that something is wrong and your voltage regulator may already be damaged. Check all connections for shorts to the regulator cover or regulator base."

That's where I'd start: taking a really good look to see if any part of the VR case (including the screws underneath) is touching the generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Seth - Jefferson, Ohio on Monday, May 29, 2017 - 02:43 pm:

Stray discharge, isn't that a sneeze?


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