Making 12 volt generator field coils

[ndnchf]

Ford generator field coils have become very expensive lately, and in some cases hard to find. I needed a set of '39 - '54 style12v generator field coils. So this morning's project was to make a set. Each coil was wound with 275 turns of 21 gauge magnet wire. They were then wrapped, terminals soldered on and then connected together. Its a lot of work to make them by hand one at a time. But the result is worth it.

[hotcoupe]

Looks good, how did you determine that it required 275 turns. And what would happen if you missed it either way by one or two turns? I think this is very interesting.
Tom

[ndnchf]

Originally Posted by hotcoupe

Looks good, how did you determine that it required 275 turns. And what would happen if you missed it either way by one or two turns? I think this is very interesting.
Tom

By uncoiling and measuring an original 12v coil. A few turns more or less has virtually no impact on performance.

[corvette8n]

Impressive work.

[glennpm]

Excellent, love seeing posts like this.

[The Art Doctor]

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I too love this sort of stuff. I see you are from F'burg. I graduated from Mary Washington in '97 with a degree in Art History. It was the good old days there with a 4 to 1 female to male ratio and less than 1,500 students on campus. I have only been back a few times when traveling by on I-95 and each time that I was drawn in I had to go straight to Carl's Frozen Custard.

[Tim Ayers]

Originally Posted by glennpm

Excellent, love seeing posts like this.

Agreed and me too. Very impressive.

[Kurt in NJ]

A sunnen honing machine makes a good coil winder and also great at kingpin bushings

[rockfla]

Originally Posted by hotcoupe

Looks good, how did you determine that it required 275 turns. And what would happen if you missed it either way by one or two turns? I think this is very interesting.
Tom

Tom


I had a fellow here in town re-wind some electro-magnets for some trafficators I have. He used a mathematical formula which takes into account the volts/amperage of unit, the need of volts/amps say for start up and running, THEN the amount of space you have in which to locate the unit THEN you can figure the diameter and length of wire required to handle and operate the unit. FOR example it took a little over 100' of small copper wire (I forget the diameter) to rewind the electo-magnets in my trafficators to have it operate properly for as low as 4 volts and up to the stock 6 volts of the system.

[KiWinUS]

A Craftsman at work. Love it.

[rotorwrench]

I've seen those winding machines. I assume you made your own spool to form the coil. It looks like you cut it from the thin ply wood used in cabinet making. Bending the coil to the case contour would be the next job before wrapping it. Looks good.

[flatford8]

Steve’s rebuilt generators look like a work of art….and he’s a real good guy to deal with….Mark

[ndnchf]

Originally Posted by rotorwrench

I've seen those winding machines. I assume you made your own spool to form the coil. It looks like you cut it from the thin ply wood used in cabinet making. Bending the coil to the case contour would be the next job before wrapping it. Looks good.

Yes, I have my son 3D print a form that goes between the slotted plywood pieces. I have a form for the earlier 3-brush fields too. Forming them - I use a generator body cut in half with a form and arbor press. Then each set is test fitted to be sure it fits properly.

[hotcoupe]

Originally Posted by rockfla

Tom


I had a fellow here in town re-wind some electro-magnets for some trafficators I have. He used a mathematical formula which takes into account the volts/amperage of unit, the need of volts/amps say for start up and running, THEN the amount of space you have in which to locate the unit THEN you can figure the diameter and length of wire required to handle and operate the unit. FOR example it took a little over 100' of small copper wire (I forget the diameter) to rewind the electo-magnets in my trafficators to have it operate properly for as low as 4 volts and up to the stock 6 volts of the system.

Thank, Rockfla all that is way above my pay grade! HAHAHA.
Tom

[Tim Ayers]

Originally Posted by ndnchf

Yes, I have my son 3D print a form that goes between the slotted plywood pieces. I have a form for the earlier 3-brush fields too. Forming them - I use a generator body cut in half with a form and arbor press. Then each set is test fitted to be sure it fits properly.

Wow. Kudos.

[ndnchf]

Here is the end result - restored 8ba generator converted to 12v negative ground. On the test bench it puts out over 30 amps

[glennpm]

Originally Posted by ndnchf

Here is the end result - restored 8ba generator converted to 12v negative ground. On the test bench it puts out over 30 amps

Great job!