By Carlos Mano Updated Mar 24, 2022
A linear motor operates on the same principles as a conventional motor, harnessing electricity and magnetism to create motion. Unlike a rotary motor, a linear motor moves a load in a straight line. They are commonly used in rail‑based systems such as trains, monorails, and amusement‑park rides, and they also serve as the core of linear accelerators. The concepts behind linear motors are ideal for educational projects and future‑tech prototypes.
Lay a flat track and install a series of alternating permanent magnets beneath it, with north (N) and south (S) poles facing upward. As the vehicle moves along the track it will encounter these poles in sequence, creating a magnetic gradient that drives motion.
Position two conductive wires on the track’s surface—one on the left side and one on the right. Between each pair of magnets, lower the wires so they cross over. This crossing causes the vehicle’s electromagnet to reverse polarity as it passes each magnet, ensuring continuous forward thrust.
Connect the wires at the track’s start to the terminals of a battery or DC power supply.
The vehicle’s core component is an electromagnet. You can purchase a ready‑made coil or construct one by wrapping several feet of enameled copper wire around an iron core. Position the coil so its end is close to the track’s magnets; the core may extend slightly below the vehicle’s chassis.
Attach one end of the coil to the left track wire and the other to the right track wire. Ensure solid electrical contact so the coil can be powered continuously as the vehicle moves.
Run the vehicle and observe its motion. The electromagnet should flip polarity when it approaches a magnet that would otherwise repel it, allowing the vehicle to be pulled toward the next magnet while the previous one pushes it forward.
Adjust the spacing between the track magnets and the precise location where the wires cross to optimize speed and smoothness. Small tweaks can significantly improve performance.
Using conductive rollers at the vehicle–track interface reduces friction, but finding electrically conductive rollers can be challenging.
Continuous operation can damage the vehicle if not properly managed. Extend the track beyond the alternating magnets and install a cushioned stop at the end to absorb impact and protect the motor and vehicle.
