Rotary Spark Gap Generator – Tesla Comes to Life

Rotary Spark Gap Generator

One advantage we have at Surplus Sales is an enormous warehouse. We can use it to store any number of big, bulky pieces of equipment… to a point. Waiting for the “demand” pendulum to swing back in its direction, creating a market for an otherwise outdated device, can take eons. One such delightful component is our Spark Gap Generator. In our current inventory are 50 new in the crate CG-35ABE Modulators. Better known as the heart of the APS-20 Radar System. The APS-20 was one of the first commercially marketed radar systems in WWII. It was made by GE and was the cutting edge technology that helped win the war. An integral component to the modulator was a Spark Gap Generator. It applied high voltage repetitive switching to a magnetron. In turn the mag pulsed a 10 Ghz rf signal towards an object via a directional antenna. Then they turned off the transmitter to try and hear an echo in the receiver. Radar is a different discussion.

So the Rotary Spark Gap Generator can be removed from our CG-35ABE Modulator and reutilized in a Tesla coil to excite the primary coil. I have seen several articles on the construction of a rotary spark gap but they are all low quality, unstable solutions. The US Government spent 10’s of thousands of 1940’s dollars on these GE generators. They are built like the quintessential tank. Tungsten pins, rock solid rotor to reduce jitter and mechanical stresses to mention a few of the attributes. Everything is 115vac, 60Hz as well.

From a builder’s perspective, I always want to use the highest quality parts I can find, and then afford. To that end we offer the spark gap two ways. Either installed in the CG35ABE modulator, along with lots of other cool parts like induction voltage regulator (motorized variac), which can either accommodate high or low line voltage or speed up/slow down the spark gap motor. Also included are a large .05uF capacitor and inductor in the spiffy cabinet. The entire assembly comes in a wood crate, nailed shut in 1944, and weighing in at 1460 pounds. We will also sell the spark gap à la carte because we can sell the cabinet and other parts separately. Provided you can handle the weight and space, the whole enchilada makes a fabulous Tesla building base. Mention you read our blog and receive an additional 30% discount off of the full assembly, (EQP) CG35ABEAPS20.