Teaching AC theory

[jmorehouse24]

I have been asked to teach a Beginner AC theory class to 2nd step apes at the out fit I work for. This will be the first class I have ever put on. I have a decent amount of knowledge on AC theory, but had a few questions for you guys out there. Besides Ohms' law, what would you guys expect in a beginner theory class. Like; intruduction to transformation, series circuits, parallel circuits, etc... Also, do any of you know of any websites or books that might have information on some kind of curriculum (sp) or teaching techniques. Thanks in advance for your help.

[Hemingray Insulators]

intro to reactance in a circuit both capacitive and inductive what they do to the current (lag/lead) etc, explain the difference between kva (actual power) vs watts (apparent power) get into power factor a little bit......transformers wouldnt hurt prob just go over single phase xfmrs and what makes them work, not getting into banksquite yet. the JATC's use an AC theory book which if you were to get your hands on one would prob be of great help for ideas for what to teach...... another good thing would probably be to make sure they understand the diffence between pure resistance (which does not chande in AC or DC) and capacitive/inductive reactance that can changed it apparent resistance in ohm depending on the frequency the circuit is opperating at as this was probably the #1 concept my class had trouble understanding........

[bobelectric]

I would suggest referring of the class as students rather than "apes".

[jmorehouse24]

I would suggest referring of the class as students rather than "apes".

I will be sure to let the apes(apprentices) know that they are also students.

[topgroove]

I would start at the very beginning and show how three phase AC power is made. Any time a magnet passes over a coil of wire a voltage is induced in a coil of wire. you can make a simple 3 phase generator with a 12 volt computer power supply fan. take the fan and glue a cd on it (you'll have to either cut the plastic surounding the fan or raise the disc with a spacer). glue eight magnets on it around the edge all 45 degree's apart . take a piece of thin aluminium and glue twelve small street light photo eye coils ( the one from 2002 and older work best) on to the aluminium plate all 30 degrees apart in a circle the same diamiter as the the CD disc. lable the coils A1, B1 C1, A2, B2, C2, A3, B3, C3, A4, B4,C4. to wire it up wye look at the coils closely and notice how the tiny wire is wound. Start with A1 and make sure it has a clockwise wind. solder a piece of wire from A1 to A2 making sure it attaches to A2 counter clockwise, Than solder a piece of wire from A2 to A3 so A3 is back to clockwise and finally a wire from A3 to A4 so A4 has a counter clockwise wind. Now take a longer piece of wire and solder it to the remaining terminal on A4 ( this will be your A phase wire) Do the same thing with the B and C coils. If you arange the plate with the coils directly over the magnets on the cd disc and power up the fan with 12 volts DC the magnets will pass over the coils and produce a perfect three phase power supply with each sine wave exactly 120 degrees apart from eachother. It sounds complicated but after you've gathered all your parts it only take about an hour to glue and solder everything together. If you have access to an ocilascope its cool to see the three phases in perfect rythem all 120 degrees apart. To test voltage you'll need three larger coils of wire ( like out of a relay coil) and connect your three phases to lets say H1 of the three coils And connect the H2's all together. This will be your floating neutral. You now have a three phase AC distribution system. I forgot to mention,,, when you glue the magnets to the disc make sure they're aranged in a north, south pattern. the first magnet will have its north pole facing out and the next will have its south pole facing out and so on.

[topgroove]

http://www.stanford.edu/~hydrobay/lookat/big/pmg/fnfig-22.jpg

[jmorehouse24]

Topgroove- Thank you for the directions and the diagram on the 3 phase generator. I probably won't be able to use it in this class, but hopefully have it together by the next one.

Sbatts, the hard part about following their textbooks, is they don't have any lol. Pretty much starting from scratch here. I came up with the basic make up of electricity. How electrons work in an atom to create energy. From their into ohm's law. Once we have that down we will be moving onto series circuits and then parallel circuits. All in a day and a half.

Thanks again for the input fellas, and I will let ya know how the generator turns out topgroove.

[T-Man]

I just saw a program on the History channel called "Mad Electricity" If you can catch it do and if you can buy it better.