An Introduction to Brushless Motors

Motor selection is one of the most important choices made in any system. The motor impacts every aspect of performance and influences all other components. This being the case, any savvy engineer should be familiar with multiple options.

Brushless motors are becoming more visible in a wide range of advanced systems, including cutting-edge motion control applications. A brushless motor is designed to address many of the performance drawbacks of brushed motors, the workhorse of mid-performance industrial systems.

The Advantages of Brushless Motors

Brushless motors offer longer effective life than brushed motors, even in heavy-duty situations. They are also simpler, which alleviates maintenance issues associated with mechanical wear and tear. Under optimal conditions, brushless motors may be expected to deliver peak performance twice as long as comparable brushed ones!

One of the greatest benefits of brushless motors is the accurate performance delivered through the motor controller, based on Hall Effect sensors. These sensors efficiently detect the rotor position and regulate the unit’s speed through current in the motor coils. Leveraging this approach, brushless motors can be relied on for 85%-90% efficiency.

Three Major Types of Brushless Motors

Although brushless motors demand a higher initial investment than brushed ones, they are often worth the price. The main drawback of brushless technology is actually a source of its strength – its relatively complex controllers are not so daunting when one selects the right motor for the job.

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The main types of brushless motors are:

Brushless DC Motors

In comparison to brushed motors, which drive current from one coil to another mechanically to develop torque, brushless DC motors use electronics to manage the switching of current across the coils. They offer accurate positioning and speed for general industrial purposes.

Brushless Servo Motors

Brushless servo motors are ideal if high speed is required in a dynamic operating environment. They are designed to accurately follow changing trajectories. Many engineers choose to embed these motors directly into the relevant mechanics to deliver tight coupling and compact design.

Brushless Torque Motors

As the name implies, torque motors are designed especially to produce high levels of torque at relatively low speeds. Like brushless servo motors, they are usually embedded directly into the mechanics they drive. This provides a key efficiency advantage over conventional gear motors.

Brushless motors are fast becoming a mainstay in today's industrial automation. With efficiency and cost-effective quality, they should be considered for most new systems.