When fine control of micromotor speed matters

5th May 2020
Alex Lynn

At the 2016 Rio Olympics, Mo Farah became the first British track and field athlete to win three Olympic gold medals, after winning gold in both the 5,000 and 10,000 metre races. The secret to his success was careful control of speed to navigate bends and avoid early fatigue. Likewise, in many industrial processes, precise control of micromotor speed is essential.

Here, Dave Walsha, Commercial Development Officer at precision drive system supplier EMS, has explained when micromotor speed control paves the way for victory.

Although typically unnoticed, there are numerous everyday examples of purposeful speed control, from the speed walking city worker on their morning commute to the slow heavy goods vehicle (HGV) carrying delicate cargo. Each speed has its own importance, and finding the correct pace is often crucial for a successful end result, such as getting to the office on time or delivering cargo undamaged.

Beyond everyday occurrences, there are many industrial processes that rely on precise speed control. Micromotors power a range of equipment across multiple sectors — and being able to finely control their speed leads to a more precise outcome.

Precise processes

Any process that requires consistent and repeatable movement benefits from a precisely controllable micromotor. This is exemplified in a manufacturing facility, where consistency between product batches is crucial. Customers want a product to be the same wherever and whenever they purchase it, meaning factory processes must all perform with equal precision.

Accurate and repeatable production can be achieved by incorporating finely controlled micromotors into factory robots. This allows a fleet of robots to all perform tasks identically by performing the same movements at the same speed, ensuring all products are created equal.

As well as ensuring accurate and repeatable production, it’s important that the products are transported correctly. Conveyer belts can jam if they are powered by motors operating at disproportionate speeds, potentially causing damage and loss of product. Installing precisely controllable micromotors into the conveyer belt system, which operate at exactly the same speed, ensures products are smoothly and efficiently transported around the factory.

Control is key

Precise control is vital across the medical industry, where practitioners are dealing with potent medications and with no room for error. The micromotors inside dosing pumps and syringe devices determine the volume of chemical that is released. Releasing the incorrect amount could severely impact the patient’s health, so fine control over the internal micromotor is essential for correct dosing.

Micromotors also power surgical and dental tools. Practitioners can use a hand or foot operated control switch to change the speed of the device, which signals the control system to alter the power supply to the motor. Using a finely controllable motor ensures medical practitioners can confidently perform surgical procedures with superior precision and skill, using agile and accurate movements.

Electrical medical apparatus and automated factory equipment are key examples where precise speed control is important. However, precise speed control also spans to other sectors, such as cameras in the film industry, automated laboratory equipment and respirators for industrial workers. Fine speed control is widely important, and achieving it requires a highly controllable motor system.

The complete package

The key to fine micromotor speed control is a closed loop system. This is the micromotor’s connection point to a control system, which can continuously monitor the micromotor’s speed and make input changes accordingly. This assessing and adjusting can take place thousands of times per second, providing a robust and precise feedback loop.

A high resolution incremental encoder is an important component of the closed loop system. As the motor turns, the encoder sends a series of pulses to the control system. The closer together the pulses, the faster the motor is working. This can be likened to a musical box, which produces a higher number of notes per minute when its handle is rapidly turned.

It's important to have a sophisticated control system that can take all variables of the micromotor’s speed into account, such as changing load, so as not to undercompensate or overshoot the power sent. The motor must be dynamic, and having a low inertia will allow the speed to change more quickly.

Ensuring the motor, incremental encoder and control system all work together in synchrony is important for achieving highly accurate speed control. EMS can supply complete speed control systems for a wide range of motors, ensuring all components work well together with high efficiency.

Sourcing the complete system from a single manufacturer provides assurance of compatibility and quality. All complete systems from FAULHABER have built in protection, which will cut the power to the motor before it is damaged in the event of a fault.

As the sole UK supplier of FAULHABER motors, EMS supplies the recently launched FAULHABER series IEF3-4096 encoder. The encoder is specially designed to suit the new FAULHABER BXT brushless DC motors. The key benefit of this system is that the encoder only adds on 6 millimetres (mm) to the motor, making it ideal for use in small equipment such as desktop lab equipmentwhere depth is limited.

Mo Farah achieved Olympic victory thanks to his supreme speed control on the racetrack. Similarly fine control of micromotor speed can increase process precision in a range of industries — achieving a winning performance outside the Olympic stadium.

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