New PSRmini safety relays from Phoenix Contact
The new measure of things
The new PSRmini safety relays from Phoenix Contact are the most compact devices on the market
At the Hannover Messe 2015, Phoenix Contact launched PSRmini, the narrowest safety relay in the world with force-guided contacts. The highly compact design is possible, thanks to newly developed elementary relay technology from Phoenix Contact. The new series of devices was above all designed for use in machine building and in the process industry.
One of the stars at the Phoenix Contact stand at this year’s Hannover Messe was small, yellow, and just 6 mm wide: the smallest safety relay in the new PSRmini product range is now only slightly wider than the connecting cables that lead up to it. But hidden in its housing is a huge amount of nowledge. The experts on the safety switching devices were another key attraction, easily recognizable to all, as they wore the yellow PSRmini housing on lanyards.
How did Phoenix Contact manage to bring the standard width of 22.5 mm down by up to 70%? This was previously thought impossible by many industry experts and safety relay manufacturers.
The quantum leap was made possible by a newly developed elementary relay, the electromechanical core of every switching device. This is where the actual opening and closing of the electrical contact takes place.
The same performance data offered by elementary relays until now
Phoenix Contact consists of an N/O and an N/C contact. Despite the overall width of just 6 mm, it offers the same performance data as classic elementary relays with forced guidance. As such, the N/O contact is designed for a maximum continuous current of 6 A, so that even large loads can be switched reliably.
The special layout of the load contact makes it very short-circuit-proof. The functional principle of the drive system leads to low power consumption and is patented.
The reliability of the safety relay in practical use is of considerable significance. A robust steel spring, for example, provides constant contact force over the entire service life of the components, while the symmetrically designed magnet system ensures a high level of robustness in the event of mechanical strain.
The diagnostic contact has a redundant design and therefore also contributes to the high reliability of the safety relay. The relays can be directly installed in the ex area in zone 2, which is an important prerequisite or applications in the process industry.
New steps on the path to relay building
The technical challenges provoked by miniaturization could only be solved by a development team. The relay developers
recruited by Phoenix Contact came to the same conclusion as product managers about the safety switching devices: an entirely new way had to be found in order to construct the miniature relays.
The magic phrase was Cross Industry Innovation: the creative, systematic leveraging of technologies and processes from the broadest range of industries, so as to create something the like of which had never been seen before.
To this end, the experts decided to use methods and tools that came from the automotive and aircraft industry for developing and testing. Here the very highest demands are placed on the safety and reliability of the components.
When developing the elementary relays, the engineers took advantage of the laws of fracture mechanics. The result? A patented concept, that permits the elementary relays to be significantly reduced in size. However, it was still not entirely clear whether it could be used with a clear conscience when it came to the protection of life and limb. Certification
bodies TÜV Rheinland and VDE reviewed these questions and granted their approvals following a comprehensive series of tests. In these tests, the values of the theoretical calculations from computer simulations were confirmed in
In order to ensure high production accuracy in accordance with Phoenix Contact’s own stringent quality requirements, the forcibly guided elementary relay and all individual parts are manufactured by Phoenix Contact.
Safety relays go back a long way for the Blomberg automation specialists. Back in 2000, the first generation of the SRclassic product range was launched on the market. The product range grew continuously in the following years.
From classic emergency stop applications, to secure time relays, right through to modular concepts for DIN rail connectors, today there is a wide range of products that cover all safety requirements. Now, with PSRmini relay
technology, the path is clear for entirely new safety solutions.