Smallest DC Motors

Smallest DC Motors

Smallest DC Motors

What are Miniature DC Motors?

A DC motor, irrespective of the size works the same way. A miniature DC motor is basically an electrical machine that converts direct current electrical energy into mechanical energy. Their speed is controllable over a wider range, compared to that of an AC motor. This is achievable either by changing the voltage supply or the current in the field windings.

In the next paragraph, we discuss one of the practical examples of a small DC motor.

Miniature High Torque DC Motors by MOOG

High voltage operation is enabled by the polyester resin impregnated insulated windings. This is one motor that has a high starting torque as well as fast response. It is a high-energy rare-earth servomotor with high flux density for improved mechanical output. It also boasts high coercivity, reliability, and lightweight characteristics. Another desirable trait of these motors is that they do not demagnetize, even under severe conditions.

MOOG’s Miniature High Torque DC Motors

MOOG’s Miniature High Torque DC Motors

The brushes last long, and they are replaceable; made of metal graphite. The size of these miniaturized devices is about 0.125 and 0.187-inch diameters, with single and double extensions. The noise and backlash are relatively low, and the commutator is diamond turned, ensuring that the operation is quiet and that the brush lasts long. They also boast a high torque-to-inertia ratio, providing a peak starting torque of 1274 oz-in. When considering these characteristics, kindly note that it weighs only 6.8 oz.

Now that you know what a typical small DC motor looks like, we can go on to learn about the smallest DC motor we have in the world. The dimensions and capability will surely surprise you!

What is the Smallest DC Motor in the World?

The Guinness World Record for the smallest electrical motor in the world is held by a machine developed by researchers from Tufts University. This single-molecule electric motor is just 1 nanometer in width and it was made possible by the low-temperature scanning tunneling microscope at the University.

Demonstration of a single-molecule electric motor

Demonstration of a single-molecule electric motor

The professor in charge of this research, Charles Sykes, who is an associate professor of chemistry, explains why this breakthrough is phenomenal. In his words, “The excitement is in the demonstration that you can provide electricity to a single molecule and get it to do something that’s not just random.”

Although the concept of having single-molecule motors are not totally novel, the fact is that they are usually generated via other sources such as illumination or other chemicals. However, this new motor that is electricity-powered offers a number of benefits.

Unlike the motors that are powered by chemicals which require the addition of chemicals to a container that is bubbling with billions of molecules, the scanning tunneling microscope makes it relatively easy to measure and spin one molecule. This new technology also improves on the inherent disadvantage of using a light-powered molecular motor. The light, no matter how lightly focused it is, has a tendency to hit every molecule at once.

How the Smallest DC Motor in the World Works

According to Sykes, the metal tip of the microscope is used to provide an electrical charge to a molecule that is present on the surface of copper. The molecule had an atom of sulfur between carbon atoms and these atoms were radiating to break off into two equal fractions of 4 carbon atoms. These two atoms “arms” have the potential to work as gears or cogs that interlock and then provide the rotation.

What are the Applications of this Miniature Motor?

According to Sykes, the practical applications of this single-molecule motor are not going to materialize anytime soon. However, one potential application of such a motor is in medical devices that are used for sensing or testing. These devices usually require very tiny pipe and when we are dealing with small scale operation, the friction of the fluid is much more pronounced. If these motors are used as covering for the wall of these pipes, the fluid will enjoy a seamless motion.

Similarly, these motors will prove useful in nanoelectromechanical systems (NEMS). When electrical signals can be aptly coupled with molecular motion, scientists will have the opportunity to build signal delay lines and sensors that operate on a nano-scale.


There’s a very high chance that the DC motor you want is not the molecular motor with dimensions in nanometers. We are experts in building DC motors that will fit your required specification. Whatever your request is, be sure to contact us below. We will ensure that your intended design comes to reality.

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