man with drill
A wax motor is an inexpensive type of linear actuator device designed to push a plunger and cause it to move. It is also called a wax capsule and is used in many appliances where a small range of motion is required. Wax motors can be found in appliances such as dishwashers and older models of washing machines. Previously they were used to lock the doors of washing machines before the spin cycles were activated. Fairly inexpensive compared to magnetic solenoids, wax motors are used to operate or pump thermal control valves and actuate valves in heating mechanisms.
The three main components of a wax engine are a block of wax, a plunger that rests on it, and a heat source that heats the wax. It works very simply: an electric heater heats the block of wax when activated. This causes the wax to heat up, which pushes out the plunger. When the chain is removed, the wax cools and contracts, removing the plunger in the process. Therefore, heating or cooling the wax causes the plunger to be expelled or withdrawn.
Sometimes counter springs are built into the motor or spring force is applied from external sources to push the plunger into the housing. A wax motor is almost maintenance free 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 in. A wax motor is preferable to a magnetic solenoid in some cases because it has a much smoother and more consistent operation. Compared to a solenoid, its activation and return are slower and, as a result, its operation is less noisy. Wax motors also use resistive loads, and those that are controlled with the help of triacs do not need snubber circuits.
It is also easy to verify that they are functional by measuring the resistance; it is easy to detect a short circuit or an open circuit. As long as the resistance between the two terminals is within a certain range, the device is functional. One of the biggest advantages of this motor 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.
Conversely, a solenoid in the same situation can burn out. Solenoids are also expensive compared to wax motors because they contain steel and copper wires. The motor also weighs less than a magnetic solenoid and is quieter; solenoids often make clicking noises. However, speed is an advantage of solenoids, and they only need milliseconds to work, unlike wax motors. It can take more than half a minute for the plunger to fully come out on a wax motor.