Plough Book Sales

Here you get two discussions on the winding of transformers.

First you get "Designing and Building Transformers" from 1938 which covers power transformers for 25 to 133 cycles per second up to 1500 watts published by Technical Service Publishing Company in Chicago.

You wrap wire around steel. That's the primary. You wrap another coil wire around the same steel. That's the secondary. You put AC power into the primary, and the AC voltage coming out of the secondary will be proportional to number of turns in the windings. For instance, if you have 300 turns on the primary and 30 turns on the secondary, you have a ratio of 10 to 1. If you put 110 volts into the primary, you'll get 1/10 that voltage out, or 11 volts. And since very little power is lost, you'll get out 10 times the current going into the primary. You could put 20 amps into the primary and get 200 amps out of the secondary. Of course, that assumes you use wire and a core that's big enough.

This cookbook will show you with many tables and examples how to design and build a power transformer to do what you want. Do you need 2000 volts out at 3/4 amp to build a transmitter power supply? Or 5000 volts out at 1/5 ampere to drive a Tesla coil? You do you need a transformer to take AC off a windmill alternator at 80 volts and drop it to 12 so it can be rectified and used to charge batteries? You may have to wind your own transformer.

You'll learn how to choose the right transformer cores given the amount of power you want to transform and the kind of steel you're using. If you can't find modern silicon steel, the author will show you how to make a working core using stove-pipe steel from the hardware store.

The tables will tell you how many turns of what size wire you'll need on both windings. You'll get basic illustrations of a winding jig and core jig, along with info on autotransformers, and other things as well.

This not theoretical, so you're not going to wind a 5000 watt 12,000 volt transformer. If you try, you're an idiot. That's far too dangerous. But this can help you and I in our experiments. You might be able to scale this up to provide 40 volts at 200 amps and end up with an arc welder.

The second discussion is seven pages from 1922 on induction coils - you know, those things we call ignition coils - written by one of the best-known experts of the time: Charles Underhill. You get basic theory, test characteristics, current waveforms, primary forms, secondary-type coils, design of windings and core, tables, insulation recommendations, interrupters used and more.

Code No. 014495