Brushless Motors For Smooth, Efficient Motion Control
Brushless Motors are one type of electric motion control device. They are also called electronically commutated motors or shortened to BLDC motors or EC motors.
These devices are one variety of synchronous motor, which means the shaft’s rotation remains synchronized with the frequency of the supply current.
Brushless motors work with direct electrical current, often referred to as DC power. Brushless motors are specially designed to convert this current into mechanical energy, which can then be used to power all types of equipment. This conversion requires the addition of an inverter or power supply that switches standard AC to DC electricity.
The operation of a brushless motor amounts to a smooth, quiet, low friction, spark-free, and continuous performance. They are a significant enhancement over brush-style or brushed motors. A brushed DC motor also runs on direct current to convert electrical power into torque or mechanical energy.
In a brushed motor, a carbon brush is used as the motor’s commutator. This component permits the flow of current to the stator, which then generates an electromagnetic field. This field reacts with the motor’s permanent magnets. The resulting resistance will flip the field continuously and generate rotational motion.
Brushed DC motors are still used in many applications, including various heavy-equipment settings like cranes and propellers, as well as household devices like hairdryers. They remain a reliable option for the generation of mechanical power in certain applications. They are, however, less prominently used since the development of brushless motors, which came about with the development of solid-state electronics in the middle of the 20th century.
The phaseout of brushed motors in favor of the brushless variety has occurred mainly due to the inevitable wear of the motor’s brush commutator. This component can contribute to sparking, higher-operational temperatures, increased weight and size, and shorter operational life compared to brushless motors.
Instead of a brush commutator, DC brushless motors use an electronic servo system to charge the stator’s electromagnets. When this charge is introduced, the stator reacts with the rotor’s permanent magnets and starts to spin, thereby converting the charge into mechanical energy.
Since brushless motors use such a system instead of a carbon brush commutator, there are fewer parts to wear down or generate heat and friction. The motor’s size and weight can also be greatly reduced or scaled up.
The longevity of the brushless DC motors is also greatly improved and is mostly dependent on the lifetime of the bearings that secure the motor assembly.
In sensored brushless motors, the efficiency of operation is enhanced with the addition of an electronic sensor, which detects the position of the rotor and provides feedback to the motor’s controller. This allows for optimal synchronization between the controller and the rotor. The sensor will help establish a closed-loop system, amounting to smoother, faster start-up and precise operation.
The sensored variety of BLDC motors are best suited for short duty-cycle, low-speed, high-efficiency operation. These motors are useful in equipment meant to be run for shorter periods of time that must also start quickly and run smoothly.
Whether brushless DC motors include or lack positional sensors, they offer many advantages over the brushed variety. Low noise, weight, and heat make them suitable for many handheld tools. Small brushless motors can be made for very compact placements, including small fans and pumps, cordless tools like drills, screwdrivers, saws, and rotary devices, as well as many medical electronics.
Without the sparking or fire hazards posed by brush-style motors and with expanded operational life, BLDC motors can be made to handle heavy industrial applications, especially where smooth continuous motion is needed. Large brushless motors are applied to electric vehicles, aircraft, and marine vessels, as well as industrial drills, pumps, heating and refrigeration systems, and all types of automated machinery.
There are many reasons why brushless motors have earned a reputation as the workhorse motor. Their strength, longevity, reliability, and many other factors have contributed to their prevalence. While they are versatile, the right design and hardware selection is crucial. Additionally, the choice of motor manufacturer or supplier will factor into the results.
In general, most types of brushless motors can be acquired as standard components, which will function as drop-in devices in many common systems. Such motors can be acquired from electronics parts distributors and larger manufacturers.
If brushless motors are needed for original equipment, or if they must be modified or enhanced for an equipment upgrade, such devices can be gained from manufacturers with engineering and production service capabilities.
Although motors serve a fairly common function, which is the conversion of electrical energy into mechanical power, numerous variables will determine how this is accomplished, where the device can be applied, and virtually countless other performance parameters. All of these factors are determined in the motor’s initial design stage and beyond. Working directly with an electrical motor manufacturer can help demystify and streamline the selection process, as well as any customizations.