My cutout

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Model T Ford Forum: Forum 2017: My cutout
Top of pagePrevious messageNext messageBottom of page Link to this message  By tommy coffey on Sunday, December 10, 2017 - 08:10 pm:

When I removed and disassembled my generator, the first time, I checked my cutout. I found there was no connection between the diode and the flat strap near it. See the pic with the ink pen pointing to the connection. I bent the strap to make a connection.

Did I do the right thing? Was something missing that should have been making the connection? I had to move the flat piece about 1/32 inch.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Harper - Keene, NH on Sunday, December 10, 2017 - 08:37 pm:

Hi Tommy,

Methinks that what is missing is solder! Time to get out your iron and roll of solder and get busy! Good luck with your project, Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, December 10, 2017 - 09:26 pm:

If the marking on the side of the diode is in fact correct then your cutout still won't work because it is backwards for a Model T. The generator puts out a voltage that is higher than the battery to thus forward bias the cutout diode and start charging. This one is only gonna charge if the battery is wired positive ground and the generator is re-polarized in that direction too.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, December 10, 2017 - 09:29 pm:

If you have been running the car with this as a cutout and your T is not positive ground then you probably damaged the generator since it would be running with no load on it at all unless the diode is/was shorted.


Top of pagePrevious messageNext messageBottom of page Link to this message  By tommy coffey on Monday, December 11, 2017 - 12:05 am:

I never suspected the cutout being wrong because it has the FORD script on the cover. Maybe it's for a model A? What damage is probably done to the generator? Can it be fixed?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Monday, December 11, 2017 - 12:35 am:

I think Henry didn't know anything about a Diode. The diode replaces the (reverse current) relay under the Ford script cover. Am I right John?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Eckensviller - Thunder Bay, ON on Monday, December 11, 2017 - 06:20 am:

Tommy, what John didn't mention is that he sells a fantastic replacement for the cutout on his website funprojects.com which goes a step further and regulates the voltage output by the generator. I think they're about $65 so if you're needing to replace that diode anyways...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Monday, December 11, 2017 - 07:42 am:

Yep, John is like that. True gentleman.

Tommy, I'm certainly no expert on these things, but a generator needs a load on it, or else it will self destruct. Kinda like the difference between running an engine at full throttle with no load and running an engine at full throttle pushing a car up a hill. One will not hurt it. the other will cause self destruction in pretty short order. I've never seen one, but it is my understanding that a generator that self destructs in this manner will sling molten solder off its commutator. Pull the band that covers the brushes and look and see if there's solder slung all over the inside of the generator. When I first started in antique cars, I ran a Model A generator for a short while with a bad cut out. I didn't know a cut out from a voltage regulator and also didn't have any idea I was potentially screwing up. Luckily, I did not fry my generator. Maybe you lucked out as well. It's sounds counterintuitive, but if you know you have a bad cutout, you can safely run the generator by grounding the output. Just run a wire from the generator post to a good ground. This will "Load" the generator and assuming it is still good, it will not harm itself.

BTW, I second the Fun Projects voltage regulator, but only after you have determined the generator is in good working order. John will be the first to tell you it is not a fix for a bad generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By tommy coffey on Monday, December 11, 2017 - 08:56 am:

OK thanks. So to test and see if my generator has self destructed or not, if I ground the output and start the car, what should I hope to see on the ammeter? I don't see any thrown solder on the inside of the band.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Monday, December 11, 2017 - 09:39 am:

Tommy,
Grounding the generator output will only prevent you generator for self destruction.
The ampere meter will tell nothing because all the current is grounded.
To test your generator see your post "Generator, on car service".
http://www.mtfca.com/discus/messages/708324/816437.html?1512908590

Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Monday, December 11, 2017 - 12:19 pm:

Tommy,

As Andre said, the ammeter won't tell you much. I guess it would probably show a discharge. The grounding of the generator output is not a 'test' or a 'fix'. It is just a 'trick' to be able to run the engine without damaging the generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By tommy coffey on Monday, December 11, 2017 - 08:20 pm:

What if I turn the diode around?


Top of pagePrevious messageNext messageBottom of page Link to this message  By George Hand on Monday, December 11, 2017 - 09:04 pm:

You could test the Diode !!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Tuesday, December 12, 2017 - 01:58 am:

I should just redo the build and replace the diode with the right one. Every part dealer sell it for about $6.- a piece.
John's regulator you will find here: http://www.funprojects.com/products/5055r.aspx

He also have a cutout 5055 for $31.70

I use them both and have no problems with it, You just need to BE SURE YOU HAVE A GOOD WORKING generator before setting the cutout on the generator.
Be sure the generator is OK.
https://www.dropbox.com/s/wcjcnoc6gpr2xz0/DSCN7486.MOV?dl=0
https://www.dropbox.com/s/xwj6eub7b0yf1z6/DSCN7468.MOV?dl=0

Good luck
Andre
Belgium


Top of pagePrevious messageNext messageBottom of page Link to this message  By tommy coffey on Thursday, December 21, 2017 - 10:02 pm:

I now have a diode that I ordered from Lang's. I will put my cutout together tomorrow and see what happens.
I know that the diode is facing the wrong way in the photo above. I think I will have to have a different bracket for the big end of the diode. There is not enough material there to make a hole big enough for the diode.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rod Barrett - Anderson, IN on Friday, December 22, 2017 - 09:16 am:

I would recommend purchasing a new voltage regulator from Fun Projects. What you currently have is a Zener Diode which conducts a large amount of current and creates heat. That is why the solder melted. The Fun Projects regulator uses a transistor which does not have the heat and current problem.

http://www.electricalbasicprojects.com/voltage-regulation-circuits-voltage-regul ators/

YMMV, Rod


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Story on Friday, December 22, 2017 - 09:34 am:

Buy Johns regulator and quit fiddling with a diode or anything else, an set back and drive like you do with your modern car. If you set the brushes to keep up with your lights It will charge to much when you don't use them. generators are to expensive to keep fiddling.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, December 22, 2017 - 09:56 am:

I will say that a cut out is good to have around when it comes time to troubleshoot. I know you are not supposed to flash a generator with a FP VR on it, and I'm thinking you probably ought not put a meter on it either. If you think you have generator problems, you can put a cut-out on it and troubleshoot to your heart's content.


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