Automatic transport systems and mobile robotics solutions, which can already be found in many warehouses and production halls today - and will be even more prevalent in the future - often carry out work without human assistance. However, an employee usually has to be on hand to make the conventional plug connection that is required to charge the batteries, for example. What's more, with this conventional solution, burnt, bent or dirty contacts lead to time-consuming and costly production downtime. This applies in particular to applications in which frequent mating cycles are required or where special challenges are posed to products or processes. If several mobile devices are used for horizontal, ground-level transportation of goods in spacious halls or buildings, for example, manual charging of the batteries significantly limits the process flow.

Contactless energy transmission is ideal for applications with circular movements, for example in rotating applications in robotics, the food and beverage industry, at handling stations or in logistics.

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Specifically, with FreeCon Contactless, a magnetic field is generated on the primary side via a coil. The receiver also consists of a coil in which a voltage is induced by the magnetic field. As soon as an electrical load is applied to the coil, a current flows and electrical power is transmitted. The increased heat development resulting from the transmission principle is countered with an innovative thermal management system. This ensures that the device can be touched by hand during operation without getting burnt and also allows for a compact system design (100 mm × 100 mm × 47 mm / W×L×H).

Another special feature of the solution is that the system can be switched directly via PLC control without the need for an additional contactor. In general, the concept is designed for industrial use. Accordingly, the system has a housing with a high protection rating of IP65, for example. It can be mounted either directly, via a mounting bracket or via a slot profile, with three different sides available. This gives the user a high degree of flexibility during installation.

As a result of contactless transmission by means of inductive resonance coupling, the secondary side - in contrast to the plug connector - can be brought to the primary side from any direction and can also be rotated. The precise coupling of the system is achieved by means of a precise position control, known as 'advance pairing'. As soon as the two modules are facing each other, the connection is established. As already mentioned, an automatic connection can be made directly via PLC control.

The areas of application for such a solution are diverse: the system is basically suitable for applications in which plug connections are frequently plugged and unplugged today. This includes changing tools on a robot, for example, where several hundred to a thousand tool changes are often carried out per day. The contacting connection must therefore be plugged and unplugged frequently, which leads to high contact wear and subsequent phenomena such as contact burn-off. The consequence of this is a loss of quality in production. In order to prevent this, regular maintenance results in high costs.

Other conceivable applications are, for example, rotary indexing tables or applications that currently work with a slip ring.

In a further expansion stage, bidirectional data transmission is to be integrated into FreeCon Contactless. The aim is to achieve a maximum data transmission rate for Profibus of 12 Mbit/s.

Author: Klaus Leuchs is Product Manager at Weidmüller.