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Brake controller and monitor needs no sensors

10 September, 2015

Mayr Power Transmission has developed an intelligent brake control module that not only energises brakes, but can also monitor them without using sensors. The Roba-brake-checker is said to be easy to integrate into existing systems and Mayr predicts that it will open up new possibilities for the monitoring of electromagnetic safety brakes.

The module recognises the switching condition of the actuator and the wear on the brake linings, and detects safety-critical conditions before they become dangerous. Any changes in the braking torque can be detected instantly, and countermeasures initiated to ensure safety.

The module is designed for an input voltage of 24V or 48V DC, and can control brakes with a nominal coil currents of 5A or 10A. Compared to fast-acting rectifiers, it offers a wider DC input voltage range of 18–30V or 42–54V, and a controlled output voltage. Also, higher cycle frequencies are possible.

The module detects when the brake condition changes – for example, whether the armature disk has been attracted or released. An output signal of the switching condition avoids the need for the usual microswitches or proximity sensors.

The brake controller operates without mechanical contacts and is wear-free, and independent of the cycle frequency and count. It avoids the need for extra wiring and possible sealing of switches and sensors. In addition, the sensorless condition monitoring allows over-excitation times to adapt automatically, if required.

May's Roba-brake-checker module energises and monitors electromagnetic brakes

By comparing the tightening and holding currents, the module can detect a possible wear reserve or line breakage, or unacceptable heating. It can be used with many of Mayr’s Roba-stop brakes, and can be built into control cabinets.

For applications that need braking torque control as well as condition monitoring, Mayr offers a variant called Roba-torqcontrol, which adds the ability to change the level of braking torque during operation by controlling the current and voltage, allowing machines to be decelerated evenly and gently. 

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