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Module controls braking forces for gentle deceleration
Published:  08 May, 2015

The German braking and torque limiter specialist Mayr Power Transmission has developed an electronic module that decelerates machines evenly and gently when they are braked. The “intelligent” braking torque control module is designed to be used with Mayr’s Roba-stop safety brakes.

Mayr points out that, unlike car brakes, machinery safety brakes usually have only two operating conditions – “braking torque present” and “no braking torque present” – and that every braking procedure applies the maximum braking torque. The new control module generates a variable braking torque that decelerates machines evenly and gently.

“Nobody would even think of using the handbrake or parking brake when a car is going at full speed,” says Mayr. “In order to decelerate the car as required, a driver would use the foot brake. Gradual, even deceleration is also often desired for devices and machine applications with dynamic braking actions.”

Until now, brakes for machines with variable loads have been dimensioned for the maximum load. However, it is not always ideal to apply the full braking torque suddenly. For example, rapid deceleration can damage goods that are being transported.

The new control module monitors the operating conditions, and regulates the braking torque accordingly. It can vary the contact force on the brake linings – and thus also the braking torque – to decelerate machines gently. It can also compensate for uneven braking torque in applications requiring a constant braking torque within narrow tolerance limits.

Mayr's module controls braking forces and deceleration rates

The new module operates from a 24V or 48V DC supply, and can control brakes with nominal coil currents of 5A or 10A. Using a pair of digital inputs, the brake rotor’s clamping force can be specified to be 25%, 50% or 75% of the nominal spring force. Alternatively, a continuous 0–10V analogue signal can be applied.

The switching device can determine whether the armature disk is attracted or has dropped, without needing a sensor. This allows it to adjust the over-excitation time automatically. Because the device registers the switching condition of the brake, no microswitches or proximity sensors (and their cabling) are needed. The 30 x 69 x 103mm module, which can be integrated into control cabinets, also takes possible wear reserves into account, and can recognise high temperatures.

According to Mayr, the module can control brake movements intelligently, making it ideal for use in the smart, interconnected machines of the future.