We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Machinery

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is a Wax Motor?

By Lakshmi Sandhana
Updated: May 17, 2024
Views: 13,627
Share

A wax motor is an inexpensive type of linear actuator device that is designed to push a plunger, causing it to move. It's also called a wax capsule and is used in many appliances where a short range of motion is required. Wax motors can be found in appliances like dishwashers and older models of washing machines. They were used earlier to lock the doors in washing machines before spin cycles were activated. Quite economical when compared to magnetic solenoids, wax motors are used to operate or pump thermal control valves and drive valves in heating mechanisms.

The three major components in a wax motor are a wax block, a plunger that bears on it, and a heat source that heats the wax. It operates in a very simple manner — an electric heater heats the wax block when it is activated. This causes the wax to heat up, which drives the plunger out. When the current is removed, the wax cools down and contracts, withdrawing the plunger in the process. Heating or cooling the wax, therefore, causes the plunger to be ejected or withdrawn.

Sometimes, countering springs are incorporated into the motor, or spring force is applied from external sources to push the plunger back into the housing. A wax motor requires almost no maintenance and offers many advantages over magnetic solenoids, which are used for the same purpose. Magnetic solenoids use a coil of wire to create a magnetic field.

This field is used to push the steel plunger out or pull it in. A wax motor is preferred over a magnetic solenoid in some cases because it has a much gentler and smoother operation. In comparison to a solenoid, it is slower to actuate and to return and, as a result, is less noisy in operation. Wax motors also use resistive loads, and those controlled with the help of triacs don't need snubber circuits.

It's also easy to check if they are functional by measuring the resistance; it's easy to spot a short or open circuit. As long as the resistance between the two terminals falls within a certain range, the device is functional. One of the greatest advantages this motor has over a solenoid is that it is less prone to failure. A wax motor survives in situations where the plunger is blocked and cannot travel all the way.

In contrast, a solenoid in the same situation may burn out. Solenoids are also expensive when compared to wax motors because they contain steel and copper wire. The motor also weighs less than a magnetic solenoid and is quieter; solenoids typically produce clicking noises. Speed is an advantage of solenoids, though, and they only need milliseconds for operation in contrast to wax motors. It may take more than half a minute for the plunger to fully push out in a wax motor.

Share
About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By anon1006786 — On May 21, 2022

Good article. I'm studying this wax motor recently. It seems like it's also called "thermoactuator". I'm considering to use it in my ventilation project.

Anyone know any manufacturers?

By anon989489 — On Mar 09, 2015

Very good article; informative.

I am investigating a wax motor incorporated into a piezo igniter on a gas stove cook top, but according to this article, it would be just too slow to repeatedly click a piezo igniter.

Is there such thing as a fast wax motor?

Share
https://www.aboutmechanics.com/what-is-a-wax-motor.htm
Copy this link
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.