Generator question 27 T

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Model T Ford Forum: Forum 2017: Generator question 27 T
Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Campbell on Wednesday, August 02, 2017 - 04:40 pm:

This generator came off an engine in a 1927. It apparently has not had a cut out on it in along time. There is a wire protruding out of the band on the end of the generator as the photo shows.
Can anyone advise the purpose of the wire??Model T generator


Top of pagePrevious messageNext messageBottom of page Link to this message  By BRENT MIZE on Wednesday, August 02, 2017 - 05:27 pm:

Robert,
It's to shunt or short the generator from working.
It's usually used when there's no cutout. Otherwise the generator will attempt to run as a motor once the engine is shut off, killing the battery and potentially causing a fire.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Wednesday, August 02, 2017 - 05:27 pm:

can not run in open circuit--will self destruct


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Wednesday, August 02, 2017 - 05:58 pm:

Not sure.
Unable to see where wire is connected on both ends.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Wednesday, August 02, 2017 - 07:18 pm:

I don't see the end of the going from the terminal to ground, I see a wire coming out of the gen running over to the terminal area but not connected to it per say. I suggested on Fordbarn that it may have been wired with one end of the field wingings being grounded like a Model A gen bi-passing the ground brush.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Campbell on Thursday, August 03, 2017 - 12:01 am:

The wire in question was connected to nothing. Just sticking out of the generator. Shouldn't this have a cut out mounted to it?? Brent-how could this run after the engine quits??

Bob


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Thursday, August 03, 2017 - 01:21 am:

Robert, without a cut out the generator is always connected to the battery, even with the ignition switch in the off position. With the engine not running, the battery will be 'feeding' the generator allowing it to act as a motor.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By BRENT MIZE on Thursday, August 03, 2017 - 07:50 am:

Bob, the generator acts like a motor when voltage is applied to the fields via the battery. The engine will not continue to run, the generator however attempts to run as a motor. It cannot turn the engine over so it's like a dead short draining the battery and overheating the windings in the stalled generator attempting to run.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 03, 2017 - 08:04 am:

I believe Mark is onto something.
I see a lot of modified generators that come into my shop for rebuilding. I would guess the the wire you see entering the case is internally connected to the main output brush and you will also find other modifications.
The original Model T generator is of the "third brush regulation" type and had a marginal power generating capacity. This is why it is recommended to keep the charging rate as low as possible to keep the battery properly charged. The one fatal flaw with this design is if the battery is disconnected and the generator has no load it will very quickly (twenty five miles of driving) internally destroy the commutator and or the field winding. As Brent points out simply grounding the generator output terminal will ground the generator internal circuits preventing it from causing further damage.
The model T generator has about one Ohm internal resistance and if you connect the terminal bolt directly to the battery without a cutout will, as Jim Bodkin stated, very quickly discharge the battery.
Whoever made this modification was probably attempting to make the Model T generator work with the later type three relay field control regulator used on 1939 and later Fords.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Campbell on Thursday, August 03, 2017 - 09:15 am:

Ron,
What are my options here. Do we get another generator and use a cut out like I suspected?
By grounding the output terminal are you saying this strange wire should be connected to the terminal next to it?? You and Brent are in an area that I don't understand.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, August 03, 2017 - 09:33 am:

I feel I need to point out that if your are using a Fun Projects Voltage Regulator - the generator is fully protected from burn out caused by the loss of load on the generator. Every VR we have made has always had a shut down circuit inside that over rides the VR instantly when the output voltage goes higher than normal indicating a blown main fuse in the car, loose battery cable, or other malady that has removed the battery connection to the VR. The lowest setting of the third brush necessary to keep the battery "up" is all that we recommend since that results in maximum generator life. That lowest setting will be accomplished if the installation instructions for the VR are followed carefully.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 03, 2017 - 12:19 pm:

Robert
You are welcome to give me a call 11 am to 4pm EST (except lunchtime), I will explain and we can a range of options to proceed.
Ron Patterson
859-881-1677


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Friday, August 04, 2017 - 12:13 am:

Set gen to 5-6 amps and and install Fun Projects V--R for trouble free touring.


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