Generator removal for Summer

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Model T Ford Forum: Forum 2012: Generator removal for Summer
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Zahorik on Saturday, June 23, 2012 - 11:52 am:

Now that it is summer here in Wisconsin, I have removed the generator from my 1926 Tudor. I figure that I don't need it. I crank the engine to start it and the magneto works just fine. There is little or no night driving. The generator weights about 16 pounds and I'm sure that even when the generator is not charging there is some HP losses just spinning it. My Tudor is heavy (so am I) so a few less pounds should help with performance.



I made a plate to cover the generator hole and added a pigtail to charge the battery if necessary.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Saturday, June 23, 2012 - 12:59 pm:

Same pigtail I use on mine. Mine hides behind the coil box attached to the terminal block.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Stitt-Southern Oregon on Saturday, June 23, 2012 - 01:11 pm:

Mike I'm kicking around the same idea. Just waiting on some plates being made..I will tell you that people have come into the shop with a 30 amp alt tied to a 3 1/2 Briggs. Even on a fully charged battery the motor labors when the alt is turned on....Typically they run it at high speed and kick the alternator on, yikes..!


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Saturday, June 23, 2012 - 07:49 pm:

Some years ago a man named Don Dechant (R.I.P.) wrote an excellent and well researched article on the operation of the Model T Ford generator. He tested it for efficiency, HP input, Amps output and operation at both 6V and 12V nominal system voltages. He graphed speeds of 20-50 MPH using standard gearing. He also actually measured the HP taken from the engine when the generator was shorted out which kills all output and loads the engine only with the bearing load caused by friction of the bearings since the field current would be zero with armature grounded and thus armature current would be zero too.

In short what he found was that for:

6V nominal operation at 12 Amp setting of the 3rd brush the results are:

20MPH 5A Charge = .15HP drawn
30MPH 10.7A Charge = .30HP drawn
40MPH 11.5A Charge = .37HP drawn
50MPH 12.3A Charge = .38HP drawn

With armature shorted to ground the results are:

20MPH = .017HP drawn
30MPH = .026HP drawn
40MPH = .034HP drawn
50MPH = .043HP drawn

These amounts of HP when the generator is grounded would be exactly the same as what the generator would be drawing when you have a Voltage Regulator on your generator and the battery is "up" as indicated by zero charge current on your dash ammeter.

I hate to see you guys do all the work of pulling off your generator since the only real savings is 16 lbs of weight but if you forget to put your battery on a charger - you will shorten the life of your battery. I honestly think you are doing a lot of work that at best is not helping much and at worst is shortening your battery life. I am going to seek permission to post Don Dechant article on my web site since it is really excellent technical lab work.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Saturday, June 23, 2012 - 08:10 pm:

All
I keep an electronic copy of Don's excellent article in my technical library. It was published in the Vintage Ford Magazine about ten years ago. I doubt the Editor of the Vintage Ford Magazine will object to my posting it on the MTFCA Forum and it is always better to ask forgiveness than to seek advance approval. grin
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Enjoy some quality engineering analysis.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Saturday, June 23, 2012 - 08:39 pm:

One more point. Sixteen pounds is the same weight as two gallons of gasoline.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Stitt-Southern Oregon on Saturday, June 23, 2012 - 08:55 pm:

Thanks John and Ron.
On the non technical observation side and mixing generators and alternators I have seen alternators doing no-more than being turned on pull a V-8 engine down at idle; key on load only. As well most folks that have tried to make battery chargers with small alternators typically have a hard time keeping the Briggs running. Of course as indicated these are alternators not generators. (no current control). I am amazed that a small gear generator producing 8 amps requires so little power.
Again anecdotal we had a fellow that tied a 100 W bulb to a bicycle via a generator. When he turned the bulb on he could barely turn the pedals,,,lol.And not for long!
Thanks again.
I will say and my comment is apple and oranges we lost a motor in our test bench and are limping with a 1 1/2 horse it is reluctant to drive any load over 10 amps. On large Alternators we could stop the 8 horse motor! Gas of course behaves differently torque wise than electric motors with respect to a casual observation.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Saturday, June 23, 2012 - 09:08 pm:

Remember that 8 amps @ 6 volts is only 48 watts.
Peanuts....... :-)


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