Most of the electric motors we see these days are of the electromagnetic variety, and for good reason: they’re powerful. But there’s a type of motor that was invented before the electromagnetic one, and of which there are many variations. Those are motors that run on high voltage, and the attraction and repulsion of charge, commonly known as electrostatic motors.
Ben Franklin — whose electric experiments are most frequently associated with flying a kite in a thunderstorm — built and tested one such high-voltage motor. It wasn’t very powerful, but was good enough for him to envision using it as a rotisserie hack. Food is a powerful motivator.
What follows is a walk through the development of various types of these motors, from the earliest ion propelled ones to the induction motors which most have never heard of before, even an HV hacker such as yours truly.
Continue reading “Ben Franklin’s Weak Motor And Other Forgotten Locomotion”
It seems like wireless power transfer is all the rage these days. There’s wireless charging mats, special battery packs, heck, even some phones have it built in! And they all use inductive coils to transfer the power — but what if there was another way? Coils of copper wire aren’t always that easy to fit inside of a product…
As an experiment, [Josh Levine] decided to try making a proof of concept for capacitive power transfer.
He first demonstrates inductive power transfer using two coils of copper wire to power up an LED. The charging coil is supplied with 15V peak-to-peak at 1MHz which is a fairly typical value for inductive charging. He then shows us two glass plates with some tinfoil taped to it. Two LEDs bridge the gap alternating polarity — since the power is oscillating, so we need a path for electrons to flow in both directions. There is no connection through the glass, but when it is set on the charging plate, the LEDs light up. The charging plate is supplied with 30V peak-to-peak at 5MHz.
Continue reading “Wireless Power Transfer Using Capacitive Plates”