Brushless Motor in Medical Applications

The brushless motor is fast replacing the brushed electric motor in many applications, medical ones in particular. The initial disadvantage of being too expensive to be used in such medical applications is changing as there is a demand for more compact, efficient and reliable equipment.

What is a Brushless DC motor?

A brushless motor, which can be found at Teco Electric Co. Ltd., is powered by DC supply and is a synchronous motor which is electronically commutated. The construction of a brushless motor differs drastically from a brushed electric motor. While in the brushed motor, the windings are fixed to the shaft of the motor; in the brushless electric motor, the windings are fixed to the housing of the motor. Yet another difference between the two is the method of commutation, which includes varying the phase currents of the motor to generate rotational torque. In brushed motors, brushes are used for commutation and in brushless motors, electric commutation takes place.

Technology of Sensor less BLDC Drive

In the normal course of things, Hall Effect devices are used by brushless DC motors to sense the rotor position. This, in turn, supports a drive to commutate the motor. Brushless motors have become very popular in medicine because low cost intelligent sensor less BLDC drives have been developed. This change in sensor less brushless DC electric drive has improved the standing of the brushless DC motor within the medical community.

The main advantage of a brushless motor is:

Sensor less BLDC drives do not need Hall Effect Devices or HFDs to give feedback from the motor.

The disadvantages of a brushless motor are:

In order to generate sufficient back-EMF for the drive to sense, the speed of the motor should be good.
If there are any sudden changes in the load, the back-EMF loop can become out of sync which may result in speed and torque loss.