Running generator without regulator,,,,

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Model T Ford Forum: Forum 2011: Running generator without regulator,,,,
Top of pagePrevious messageNext messageBottom of page Link to this message  By Rob from Nova Scotia on Wednesday, June 08, 2011 - 04:05 pm:

To all the electrical Gurus out there, If I were to run a generator without a cutout, how would I do it. I am ordering John's voltage regulator, but am curious how this works. Call it more of a learning experience, This sort of information helps me understand these systems much better. I know you have to ground the generator if it isn't charging your battery, but thats where my expertise seems to end.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Sims Reed City MI. on Wednesday, June 08, 2011 - 04:18 pm:

It would work fine, except as soon as the engine quit turning the battery would start discharging. You could put a switch in the wire and hope you turn it off. The normal cutout is just a switch itself>


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis - Lyons, GA on Wednesday, June 08, 2011 - 04:33 pm:

If you run it completely disconnected, it will self destruct in pretty short order. If you connect it directly to the battery, the battery will try to 'motor' it when you shut down the engine. It will probably run down the battery, and I suppose, could burn up the generator, but not sure about that last part. To prevent these bad things from happening, you should run a wire from the generator output terminal to ground until you get your regulator or cut out. Or you could do as above and install a switch in the circuit, but like he said, you HAVE to remember to close it upon starting and open it upon shutting down, EVERY single time, lest one the bad things happen.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Deichmann, Blistrup, Denmark on Wednesday, June 08, 2011 - 04:34 pm:

I would not expect John Regan to step in here and thorough explain in detail how his VR works, but I have come to the conclusion, that when the voltage on the battery side is around 7,2V, the electronics starts shortening the generator gradually to ground to hold that voltage, which in turn will lower the current to just a few amps.
The problem with running a generator without a cut out is, that when you stop the engine, the battery will try to drive the generator as an engine. You will then have to go out under the hood every time and disconnect the generator. Similar you would have to connect it again BEFORE you start the engine or you risk a run away generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Dwyer on Wednesday, June 08, 2011 - 04:43 pm:

You can't run the generator without a cut-out. Even in the day, Fords had a cut-out mounted on the generator (except for the very first ones). The Cut-Out will do as Jim said --- The generator generates electricity when something is turning it. But when it's not being turned, it will try to act as a motor. Since a generator can't turn over the whole engine like the starter, it will just sit there and burn out. Ask me how I know this. . .

If you run without a cut-out you need to be CERTAIN to remember to disconnect the generator from the battery when you stop engine. I wouldn't trust myself to do that.

You can run without a voltage regulator. All that does is limit the output of the generator so that you don't overcharge the battery. To run without, you just run the generator only when the battery gets low, like putting in a switch to shunt the output to ground. Then when the battery gets weak, you switch it into the battery to charge.

Alternatively you can run with a light or two on. You probably want to have only a few amps charging depending on how far you drive and how long it takes to re-charge. I run my Packard which has no regulator this way --- I essentially charge at about 2 amps by keeping lights on and that works fine. Then again, it's always about 75-100 miles every time I take the car out.

The other thing to remember is that it's always better to have a battery slightly undercharged than overcharged. An overcharged battery will boil away its electrolyte. That also happened to me. Popped the caps right off and the battery died shortly thereafter. Batteries don't like to get hot --- that's why they don't last long in places like Tucson or Death Valley.

Remember that if you use the switch method, when the generator is off you need to short it to ground. If you let it float it will develop really high voltage --- it doesn't know when to quit. Shunting it to ground is perfectly fine and returns the electrons back to where they came. (Not really, but that sounds good).


Top of pagePrevious messageNext messageBottom of page Link to this message  By John H on Wednesday, June 08, 2011 - 08:43 pm:

My guess is the accessory regulator works by shorting out the output of the generator (using a mosfet or power transistor) when the voltage on the battery side of the regulator reaches around 7V.
By shorting the output completely, virtually no power is dissipated in the power transistor. A 'gradual' short would be highly undesirable because of power dissipation. The cutout function is taken over by a diode. The circuit shown will do the job but for 6V use, R8 would need to be decreased in value, to something like 39K.regulator


Top of pagePrevious messageNext messageBottom of page Link to this message  By George...Cherry Hill, NJ on Wednesday, June 08, 2011 - 11:18 pm:

I may be the village idiot about electricity and electronics...but the one thing I have learned is that if you have a bad cutout or even think you have a bad cut-out...

You need to disconnect the wire from the generator and tape up its end because it is hot at the other end...

Take the cut-out off...

And immediately short the genrator stud to ground until you figure out whats up!

Take any chance on an open, any at all, and the gen will toast itself faster than you can form spit!

Rob, go to John's site...www.funprojects.com and he usually has all of his instruction sheets available as on line PDF...on most of his stuff he includes a story.

After my first swallowed generator over 30 years ago, I just used normal replacement cut-outs on any of my projects through the years, always new. I have a new toy, the charging circuit works great, has a cut-out of unknown age...and in my usual, it was time for a new cut-out on a just because basis. This time I said why not and ordered up one of Johns...haven't put it on yet because I'm still the village idiot on the 3rd brush setting, even after reading the MTFCA book! Will tackle that soon enough tho'

My guess and only a guess is that it regulates by sensing voltage as he is keen on exactly where the 3rd brush NEEDS to be set (Which determines amp output possible)...and then he just shunts the excess produced to ground...senses a need? Sends the juice in that direction, perhaps a few diodes to keep it one way.

As someone mentioned, John may not respond on forum...then again he just may...but one thing I have always found in dealing with John...he'll talk you through personally on just what your questions are and stay with you that way until you understand! John is that type of guy! He has actually spent more time than it is probably worth on this 3rd brush thing with me, I'm just overly complicating it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rob from Nova Scotia on Friday, June 10, 2011 - 05:50 am:

Well, I am going to bite the bullet and buy one of these regulators. My next question is this- Can I test and set my generator up without a cutout? I would hate to fry a perfectly good VR


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Friday, June 10, 2011 - 10:53 am:

You can run your generator 2 different ways w/out a cutout.

As previously mentioned you could use a SPDT (single pole double throw) switch, connecting the generator output to the centre (common) terminal, one of the other terminals would connect to the wire that original came from the terminal strip to the cutout, the other terminal would connect to ground. In one position the generator output is grounded, in the other position the output goes to the electrical system.

The other way is to use a diode in place of the cutout. (A diode is basically an electrical one way valve) You would need a diode of 40 or 50 or more amp rating and at least 25 volt PIV (peak inverse voltage) rating.
The diode is probably the better way to go as with the switch method you have to remember to toggle the switch every time after you start the engine and again before you shut it down.
The diode will do that automatically.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, June 10, 2011 - 12:06 pm:

Unfortunately everyone thinks that if a generator shows "charging" with a cutout in place that it is proof positive that the generator is good and all wiring/battery/ammeter is good too. This is simply not the case. The problem is that T generators are coming around on 90+ years of age and they have been taken apart and put back together again probably 6 times since they were new. What are the odds that all 6 of those mechanics knew what they were doing? Installing a VR on a questionable generator results sometimes in a questionable VR. Our VR is not frail but it is connected in between 2 sets of variables. On the one side is an unknown generator and on the other side is the car wiring/ammeter/battery. If there is anything wrong with either side - the VR is generally what gets blamed for what is wrong since it was installed "last". I certainly would test the generator to make sure it seems to work OK as best you can test it but I always recommend that the whole system be a known good system before the VR is installed. Our VR is not a cure for a sick electrical system as many think it is. The term "rebuilt" with regard to generators can mean anything from a totally properly redone unit to nothing more than a paint job which unfortunately is what you usually get from the "local" modern rebuilder who has no clue but says he knows "all about those old generators".

The good news is that unlike your local NAPA dealer who has a sign that reads "absolutely no warranty on electrical items", we repair broken regulators for a flat fee and try to help you solve the issue if it turns out that despite your best efforts, you have a problem and have damaged your VR. It is no fun trying to tour with electrical problems so I strongly recommend that you have your generator rebuilt before you install our VR if you have no clue as to the history of your generator. If you contact me offline I can recommend a good generator rebuilder. I can also give you some questions to ask your local rebuilder before you let him have your generator. These questions will usually allow you to ferret out the BS artists who are going to give you a paint job. Competent generator rebuilders are few and far between for T generators.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rob from Nova Scotia on Saturday, June 11, 2011 - 06:19 am:

John,
All my wiring in my T is new, coils were done by Ron. I rebuilt the generator using the MTFCA book, (my old man is an electrician, and a car guy from many years gone by) I would just like to test it and set it up properly before installing one of your VR.I would like to make sure it works properly, work out any gremlins, etc, so I don't fry a perfectly good VR


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rod Smalley on Sunday, June 12, 2011 - 07:04 pm:

I installed one of the "fun projects" voltage regulators last year. After having a “cooked “cutout, I rebuilt my generator to make sure that it would perform well. I was very concerned after carefully reading the instructions for the VR, and did not want to risk destroying the new voltage regulator. To set up the generator so as not to exceed 10 amps charging on a fully charged battery, I decided to purchase a diode from Snyders and install it inside the burned up old cutout. I then installed the diode / cut out base, and adjusted the generator third brush to deliver about 10 amps max after a fresh starting of my T ( This represents a normal battery draw down on start up). I ran this way for a couple of days to ensure that my battery was fully charged, and the max charge was not ever exceeding 10 amps. I then shut off the engine and removed the old cutout base with diode, and installed the "fun projects" voltage regulator. This procedure worked very well for me, and I love the results. I have since used my old cut out base with diode to help other T members in our club get by until they can get a new cut out or a voltage regulator.


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