Shrinking down to size

09/09/20 - Achieving high power motors in small packages

10th September 2020
Filed under: Faulhaber, 2020,

There was a time when we could only measure in centimetres and millimetres, now we can measure at sub-micron and nano level. Our yearning for ever smaller technology is driving big innovation in aerospace, medical and manufacturing technology. However, can space limitations prevent the small from delivering mighty power? Here, Dave Walsha, commercial development officer at precision drive system supplier EMS Ltd, shares his insights in achieving small yet powerful technology.

Increasingly stringent efficiency regulations and progressively smaller electronic devices have driven the need for smaller motors. In fact, the world’s smallest motor measures just one nanometre across. However, many modern engineering advancements require small motors that also have high torque and faster actuation times.

Small motors are beneficial in industries where low weight is advantageous, such as in plane interior cabin equipment and in applications where space is limited, such as in handheld medical devices. However, in these applications, size must not compromise performance — whether that’s ensuring cabin seats return upright quickly before plane landing or a surgical tool performs well with minimal exertion required from the surgeon.

Good things come in small packages

Precision is key in the medical industry, where every small movement matters during a procedure. Small, lightweight and powerful motors make hand-held surgical tools easier to handle and control, easing strain on the surgeon while performing quickly and accurately.

In the aviation industry, each milligram of weight matters. In fact, a one per cent reduction in weight leads to an estimated 0.75 per cent reduction in fuel consumption. Aerospace engineers who choose small, lightweight and powerful motors to power interior cabin equipment, such as electrically operated seat and window blind adjustment systems, will gain significant fuel savings — helping to save money and reduce emissions.

Back on the ground, small and powerful motors play a key role increasing factory efficiency. Manufacturers are under increasing pressure to produce more product in a shorter time frame. Facility managers who choose automated machinery and robots powered by small motors will increase efficiency and working capacity.

Sizing up your components

Design engineers must purposely design each motor component to achieve high power with small size and low weight.  High power magnets create a stronger magnetic field, which in turn increases torque. A high copper fill in the motor further increases torque by providing more conducting material and therefore a higher energy input.

The bearing type used in a motor can have a large impact on size and power. Choosing the right bearing will also affect the amount of friction generated from moving parts and the resulting rotational speeds. Ball bearings in particular can reduce friction while withstanding high loads and have a small diameter. Ensuring all motor components are densely packed together within tight tolerances will further reduce motor size.

EMS supplies a wide range of FAULHABER miniature brushed and brushless motors, with sizes ranging from 3mm to 44mm in diameter. The motor systems are modular, so engineers can choose from different components, such as motors and gearboxes, to form an optimised combination to suit power and space requirements. Furthermore, if standard options aren’t suitable, EMS provides a bespoke manufacturing service that enables the production of a high power actuation system to maximise the performance available from a specific space envelope.

Whether it’s speeding up surgical procedures or saving aircraft fuel, small technology is driving great engineering advancements. However, while size is important, so is power. Engineers can miniaturise products while improving performance by using small, high power motors — helping innovation to continue from the factory floor to the skies.

If you have a project that needs a drive solution with class leading power density, get in touch today.