Model T coil questions for the experts. Warning! Contains technical info!

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Model T Ford Forum: Forum 2014: Model T coil questions for the experts. Warning! Contains technical info!
Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Thursday, August 07, 2014 - 05:25 pm:

I've been working on T coils for a number of years now, and I have a few questions for the experts that aren't related to the performance of the coils necessarily. The only reason I ask them is out of pure curiosity.

First off, what type of insulation did they use for the magnet wire? Whatever it was, it sure seems to have held up well, and can stand some abuse. I typically bake the coils in the oven on top of aluminum foil at 250 degrees F for an hour or so in order to loosen the tar and scrape it out. Doesn't seem to hurt the windings at all.

Second, How many turns are in the secondary, and what gauge wire is it? I know that the primary is on the order of 180 turns or so (I know because I unwound one for fun), and appears to be around 20 gauge. I didn't actually measure it.

Third, what did Ford use to insulate the individual layers of turns on the secondary? Is it just paper? Wax paper? Something else? Kapton? :-)

Fourth, does anyone have a picture of a coil de-tarred, but with all the components in their correct places? I know what it all looks like, but I want to show a friend how it looks and works. I always wind up destroying the old condensers (boo-hoo) when I take them apart.

Thank you all for your input!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 07, 2014 - 06:34 pm:

Ford manufactured coil.
Primary 212 turns in two layers of 20 gauge wire with cotton wrapped insulation.
Secondary 16600 turns in two windings of 38 gauge wire of multiple layers insulated between layers by waxed paper.
There is a paper insulating tube between the primary and secondary winding.
1

Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 07, 2014 - 06:35 pm:

Ford manufactured coil.
Primary 212 turns in two layers of 20 gauge wire with cotton wrapped insulation.
Secondary 16600 turns in two windings of 38 gauge wire of multiple layers insulated between layers by waxed paper.
There is a paper insulating tube between the primary and secondary winding.

application/pdf1
Coil Diagram with Readings.pdf (30.8 k)


Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 07, 2014 - 06:58 pm:

Here is more data from Bruce's Model T Encyclopedia.

SPECIFICATIONS OF COIL UNIT
(1926)
Accession 94, Box 171, Ford Archives
Primary 212 turns
Secondary 16,600 turns
Ratio of windings 78 to 1
DC resistance Primary .295 ohms
Secondary 3300 ohms
Inductance Primary .0033 henrys (secondary open)
.0006 henrys (secondary shorted)
Secondary 22 henrys (primary open)
11.3 henrys (primary shorted)
Impedance at 133 cycles (25 mph) Primary 2.77 ohms (secondary open)
.580 ohms (secondary shorted)
Secondary 18.700 ohms (primary open)
9.960 ohms (primary shorted)
Capacitor .40 -.45 mfd

Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Dufault on Thursday, August 07, 2014 - 07:02 pm:

Such speedy answers...

Great people make an awesome Forum ! !


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred Dimock, Newfields NH, USA on Thursday, August 07, 2014 - 07:47 pm:

I expect nothing less from Ron.
He is an expert and a gentleman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Hjortnaes, Men Falls, WI on Thursday, August 07, 2014 - 09:38 pm:

I wonder if Ron has ever taken one apart and counted the number of turns on the primary and secondary?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill dugger on Thursday, August 07, 2014 - 10:16 pm:

I'll bet Ron wound the coil wire around his finger to count it!!!!!!!!!!!!!!!!!!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, August 08, 2014 - 07:23 am:



This is coil I removed the tar from.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Georgetown TX on Friday, August 08, 2014 - 07:28 am:


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Friday, August 08, 2014 - 09:46 am:

Thanks everyone! You all had all the answers I'm looking for!


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