Myths About Motor Control

Small electrical motors are ubiquitous. The human environment is being automated in an increasingly fast pace, driven by the desire for safety, security and health, fueled by an aging population in the highest developed countries, gadgets that go mainstream, and by new manufacturing trends that characterize the 4th Industrial Revolution.

Every day, we see new, ingenious applications for small electric motors. And while this series on myths about motor control is supposed to cover all aspects on how to control a motor, the booming market for small motors is quite different compared to the huge industrial motors, meaning there are too many myths out in the world. So, instead of talking about electric motors in general, we’ll focus on myths in the small motor market, tackling one myth a week.

Note that some aspects are true for bigger motors as well.

Myth 1: Brushed DC motors will be replaced by brushless DC motors

DC motors with an electromechanical commutation system are still highly popular in toys and simple gadgets – due to low cost – as well as in Mars rovers: Expensive, high-quality motors need only simple electronics – or none at all – and are resistant to radiation.

However: The high-volume production of all kinds of BLDC motors (brushless DC) and PMSM (Permanent Magnet Synchronous Motors) in China goes together with a sharp decline with regard to cost of the necessary motor control electronics. Technologies and algorithms formerly reserved for high-end industrial drives are now embedded in ICs. Brushless motors are far more durable, compared to their mechanical commutated ancestors – the life is only limited by the bearings, not by the brushes. This is an important factor, just because there will be more motors around, driving the need for every unit to be extremely dependable. BLDC motors do not generate electromagnetic emission caused by sparks and no dust – both side effects that do not go well in our wireless and clean tech future.

So – like the Diesel engines in cars, brushed DC motors will still be around for some time, but for every new design, the pressure of replacement by the new technology will increase. Finally, they will become niche products –unless the Mars colonization proceeds faster than expected…