Brushing With Greatness

September 23rd, 2019

With the unveiling of the DYNAMIC MOTION system, LOGICDATA took a mighty stride towards the future of adjustable technology, breaking convention by using integrated intelligent software to manage the system’s actuators, a huge leap forward from the external control boxes of old.

However, a further major change within the actuators – the introduction of a brushless motor system – has the potential to create even bigger waves in the industry. We look at why we felt the time was right to push our product range into the future and give you the lowdown on how brushless motor technology really works.

Getting more for less

On the face of it, it’s a simple business. Table goes up, table goes down. Repeat. Unfortunately, at LOGICDATA, we know that things are rarely this simple. Constant improvement and fresh ideas are the keys to leadership at the forefront of a blossoming global industry, but innovation doesn’t necessarily ensure success: it simply enables survival. As such, we see it as a minimum requirement for our entire global team, a challenge they accept with relish. We can split our pursuit of continual development into the three key demands of our customer base: extended functionality that facilitates the implementation of adjustable technology into the modern workplace; impeccable quality, reliability, and user-friendliness; and an unrelenting drive towards lower prices. Taken singularly, none of these points should pose a major problem for a company with almost 200 employees working in research and development. However, it is the combination of these sometimes-conflicting aims that makes the hugely competitive industry in which we operate so much more challenging. How can we make products simultaneously better and cheaper? How can we put our name to brand-new features and guarantee that they are reliable? Or, to condense this to a single question: How can we offer our customers more for less?

Our DYNAMIC new approach

With the DYNAMIC MOTION system, LOGICDATA addresses this issue with the boldness and vigor that have hallmarked our corporate history. Having spent more than a decade first revolutionizing, then refining Switched Mode Power Supply Control Boxes, the new, integrated control units of the system’s actuators – the DMD660, DMD500, and the DMG90 – mark a quantum shift in the way in which adjustable furniture systems should be designed. Yet it is what happens within these motors that is perhaps even more fascinating. The DYNAMIC MOTION system is the first of LOGICDATA’S mechatronic products to feature brushless motor technology, a subtle, yet immensely significant indicator of our undying commitment to technological innovation.

To help explain to you exactly why the move to brushless technology has been so significant, we’ve enlisted Senior Mechanical Engineer, Philipp Gödl, to talk you through the basics.

Hi Philipp! Let’s start from the beginning. What do the motors in LOGICDATA products actually do?

Motors convert energy into motion. We need motors because otherwise our tables wouldn’t move. To be more specific, electric motors function by creating magnetic fields between permanent magnets and electromagnets usually made from copper. When electricity is applied to the copper wiring, it becomes magnetic. The attracting and repelling forces between the permanent magnets and electromagnetic copper cause a rotor to turn. In LOGICDATA actuators, this rotation turns a spindle clockwise or counter-clockwise, which drives the table up or down. You need (at least) two opposing magnetic poles to create a motor, otherwise the motor would only turn halfway, reach the point it was magnetically attracted to, and then stop. The question of how to keep the motor turning is the real difference between “brushed” and “brushless” motor designs.

Okay! So, where do the brushes come in?

The terms “brushed” and “brushless” refer to the ways in which the electric current is applied to create the electromagnet, and how the electromagnet causes the rotor to turn. With a brushed motor, the coil is normally located centrally around the rotor. It is attracted to north or south depending on the direction of the current applied to it. The current is applied through “brushes” – usually made from graphite and alloy composites – which are placed at points around the rotor and touched in sequence by the coil during rotation. Some brushes apply current in one direction, the others in the reverse direction. This keeps the electromagnet alternating between attraction to north and south, and thus causes the rotor to turn.

Right. And how does this work without brushes?

Brushless motors, such as the ones found in the DMD660, DMD500, and the DMG90, essentially work “inside out”. Multiple electromagnets are fixed to the stationary, outer part of the motor, while the permanent magnet rotates in the center. The coils take it in turns to become electromagnets. Sensors are used to detect the position of the rotor, and to send electricity to each coil, using switches such as transistors. The coils are turned off and on in sequence, in intervals of milliseconds, which causes the motor to rotate as the permanent magnets follow the magnetic pulse around and around. As such, there is no need for contact between stationary and moving parts. By timing the pulses to match the position of the rotor, the rotor continues to turn. The faster the switching frequency, the faster the rotor will rotate.

Got it! So why is brushless such a big deal?

It is an enormous deal. While considerable improvements have been made to the design of modern brushed motors, including some of the earlier designs by LOGICDATA, what we need to remember is that this is an ancient technology, dating back to the 1800s. It wasn’t even especially cutting edge then either: Nikola Tesla was already promoting alternatives to brushed motors by the end of the 19th century.  130 years later, LOGICDATA’s move to brushless technology catapults us into the modern era as well. The main factor to consider is component lifetime: even the very slight contact between the brushes and coil on a brushed motor causes the brushes to wear out over time, and the dust created from disintegrating brushes can be bad for the environment. The friction caused by the brushing components – in addition to the fact that part-worn brushes lose their efficiency – is also a major drawback that can never really be overcome while keeping the brushes. On the negative side, while brushless motors reduce mechanical wear, the electronic circuits required to make them work are more complicated and, theoretically, less durable. However, by sourcing components well and creating sound electronic designs, we are certain that the benefits for LOGICDATA and its customers far outweigh the potential risks. Using brushless technology also makes the motors quieter, which is particularly beneficial for modern users, many of whom use shared office spaces where noise reduction is an important selling point. Additionally, we’re able to source the components for brushless motors in the EU, which generally ensures a better level of quality, efficiency, and smoothness all round – as well as reducing the need for long-distance shipping. Good news for the environment, good news for our customers!

Philipp Gödl, Senior Mechanical Engineer