Brushed vs. Brushless Motors

by Andy on May 7, 2012

When looking at power tools one thing to note is the type of motor they use. If you are working in a sensitive environment or need a tool that lasts as long as possible, you may have been told to buy products with brushless motors, but do you know why? Here we will look into what it means for a motor to be brushed or brushless.

WBTS35P Torque Screwdriver Brushed and brushless motors are types of electronic motors, so they run off of electricity rather than a fuel like gasoline. Each motor uses permanent magnets and electromagnets. By putting power through the electromagnet, you can change its polarity. As the polarity changes, it is repelled from the constant polarity of the permanent magnet causing it to rotate.

The two parts of the motor that are most important are the stator (the stationary outside) and rotor (the part that rotates). Brushed motors have the permanent magnet on the stator and the electromagnet in the rotor. Brushless motors are the opposite, with permanent magnets on the rotor and electromagnets on the stator.

Why does switching where each magnet is change the properties of the motor? The main reason is due to the electromagnet rotating in the brushed motor. Because the electromagnet rotates, there has to be some way to connect the magnet to a power supply without having direct cables (which would twist and eventually break or stop the motor from running). This is where the brushes come in; two sets of charged brushes are placed on either side of the rotor, causing the polarity to flip as it rotates. Friction from the brushes not only slows down the motor as it runs, but can also cause sparks and debris.

With a brushless motor, you can have cords running to the stationary electromagnets. Instead of the polarity changing naturally as the rotor moves, you need a small computer controller to turn the electromagnets on and off. This makes the motor more precise, but also more expensive. Also there is very little physical contact with the rotor, greatly reducing friction on the moving parts, leading to higher efficiency and a long lasting motor. One downside to the brushless motor is that it can take more power to get it to start, but it often makes up that power later through its efficiency.

Overall, tools with brushless motors can be a great addition to your workplace. The initial monetary investment can make a huge difference as you do not need to replace parts as often and you can have more reliable tools. Also, brushless motors can reduce workplace contamination, as friction from the brushed motor can leave particles behind.

All-Spec Industries carries a number of tools with brushless motors, including Weller Torque Drivers, Master Appliance Heat Blowers, and Edsyn Fume Extractors. Place an order online at www.All-Spec.com, or call our customer service at (800)537-0351 today!

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