Automatic Gap Controller

WolfTronix was asked to build  an automatic gap controller, for a New Generation Hub Motor for the Solar Stealth (Columbus North High School Solar Car), based out of Columbus, IN

The New Generation Hub Motor has a user adjustable air gap, which is equivalent to a transmission on a car

When the gap is all the way closed, there exists high magnetic coupling, thus producing large amounts of torque, but limits the motor to low RPM (you want this when starting after being stopped, and when going up a hill)

When the gap is all the way open, there exists low magnetic coupling, thus producing high RPM, but at a low torque (you want this when running at a fixed power consumption cruise control)

The Gap Controller has two modes Auto and Manual, when in Manual the driver can adjust the gap location using a set point, when in Auto mode an algorithm attempts to optimize the gap location to maximize RPM

The Controller consists of two units, an input/display module, and a servo module

The input/display module displays the current RPM, set point, location of the servo (value and bar graph), Mode and User inputs

It took about a week to design and build the controller:

Prototype bread board design of the input/display module, micro and LCD display


User inputs, momentary toggle (set point adjust), and push button (mode select)

Prototype bread board design of the servo module, micro and H-bridge


Gear head motor and 10 turn potentiometer, what actually moves the gap

Display read outs in the different modes respectively: 

(splash screen)  (set point)  (auto)  (moving)


Final input/display module (Front)


Final input/display module (Back)


Final servo module

I will post final installation pics when the Solar Car team sends me them