If you have ever wanted to make a Tesla coil, but have been too daunted by the process of hand-winding the secondary, then this Instructable is for you. In this instructable, I will show you how to wind a Tesla coil using an easily built machine, not a lathe, and how protect the windings. The video below will visually show you how to wind it. Lets get started!
To calculate the amount of wire you will use and how long the pipe is that will be used, you first need to know that you will need approximately 1000 turns. You can then plug in the variables into the equations below to find out how long your coil will be, how much wire you will need, how many turns you will have, wire gauge, and wire diameter. Many coils have different wire gauges and lengths. You can use these equations to find specifications for your coil.
totalWire = pi*pipeDiameter*turns
coilLength = wireDiameter*turns
To prepare the pipe, you will first need to cut it. Cut it to the length that you determined using the equations in step 2, and add about 2 inches. Then, use a wet paper towel to clean all of the dirt and pipe shavings off the coil. It is important that you keep this very clean. Impurities on the pipe can cause arc-over when this is used in a Tesla coil. Wait for the pipe to completely dry before continuing to the next step.
This is the most important part in winding the Tesla coil. The winding machine allows uniform windings at relatively high speeds. A Tesla coil winding machine can be built relatively quickly and easily. I built my winder using aluminium bars, rubber wheels, and a geared motor, but you can build it out of anything that works. This kind of tesla coil winder uses 4 wheels to rotate the piece of PVC pipe around its center axis. One wheel has a geared motor attached to it which lets the pipe be rotated automatically. This can also be built using an upside-down RC car and something with wheels, but because every reader has different materials, I will leave building the winder up to the readers imagination. Ask questions in the comments for help with building the winder. To control the motor, I used a variable power supply.
To wind the coil you will first need to take your pipe, and tape one end of the wire to one end of the pipe. This will hold it in place during winding, then tuck the wire inside the pipe. Then, put the spool of wire vertically on a bolt so it will be able to rotate while the wire unwinds from it. After that, use an empty spool as a guide for putting the wire in the right place while using your thumb to compress the wire together. This step is better explained through the above pictures and the video referenced in the intro. This step takes about an hour to perform because of the about of turns needed for a tesla coil.
To test your Tesla coil, first you need to test the resistance of the windings. I used a multimeter to test resistance to make sure the wire had not broken. It should be >50 ohms. To test the resonant frequency of the coil, attach a top load(pie tin) and build a slayer exciter circuit(in my upcoming instructable). Then measure the frequency with an oscilloscope. The resonant frequency of my coil is 380 kilocycles.