Copper sheets replace motor windings

Nov. 7, 2002

Electric dc brush motors have traditionally used wire-wound armatures that move through a magnetic-flux air gap. Engineers at ThinGap Motor Technologies, Santa Barbara (, have come up with an alternative, precision-machined copper sheets. It gives motors a higher copper-packing density and a higher ratio of copper to total volume. It also puts more copper in the magnetic field, which translates into better motor performance and efficiency. ThinGap indicates the technology can be used to build motors that are more than 90% efficient.

Since there are no windings or slots, the motor generates no slot harmonics and no ac excitation of any noise, so they run quiet. There is no iron in the coil, so there is no cogging or hysteresis, and torque ripple due to harmonics is minimal. Both sides of the coils are exposed to airflow, so heat dissipates quickly. And the coil lets designers narrow the air gap between the permanent magnet and the magnetic return structure, allowing better use of the available magnetic-flux density. The motors also have higher power-to-weight ratios. The TG3300-35B brush motor, for example, weighs 35 oz but puts out 700 W continuous power, 71 oz-in. of torque, and can spin at up to 30,000 rpm.

Sponsored Recommendations

The entire spectrum of drive technology

June 5, 2024
Read exciting stories about all aspects of maxon drive technology in our magazine.


May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

Solenoid Valve Mechanics: Understanding Force Balance Equations

May 13, 2024
When evaluating a solenoid valve for a particular application, it is important to ensure that the valve can both remain in state and transition between its de-energized and fully...

Solenoid Valve Basics: What They Are, What They Do, and How They Work

May 13, 2024
A solenoid valve is an electromechanical device used to control the flow of a liquid or gas. It is comprised of two features: a solenoid and a valve. The solenoid is an electric...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!