Function ROBA-stop®-M brakes are spring applied, electromagnetic safety brakes.

Spring applied function:2016-06-07_1051

In de-energised condition, helical springs (6) press against the armature disk (5). The rotor (3) is held between the armature disk (5) and the corresponding mounting surface of the machine. The shaft is braked via the toothed hub (1).


When the power is switched on, a magnetic field is built up. The armature disk (5) is attracted to the coil carrier (2) against the spring pressure. The brake is released and the shaft is able to rotate freely.

Safety brakes:

The brake brakes reliably and safely in the event of a power switchoff, a power failure or an EMERGENCY STOP.


Advantages for Your Applications

❑ Simple installation

❑ Brake outer diameter completely enclosed (higher protection can easily be realised)

❑ Magnetic coil is designed for a relative duty cycle of 100 %

❑ Magnetic coil and casting compound correspond to class of insulation F

❑ The nominal air gap is specified by design and inspected

❑ Short switching times

❑ Maintenance-free over the entire service lifetime of the rotorroba_stop_m

Installation Conditions

❑ The eccentricity of the shaft end in relation to the mounting pitch circle must not exceed 0.2 mm.

❑ The positional tolerance of the threaded holes for the cap screws (Item 8, Fig. 2) must not exceed 0.2 mm.

❑ The axial run-out deviation of the screw-on surface to the shaft must not exceed the permitted axial run-out tolerance acc. DIN 42955 N. Larger deviations can lead to a drop in torque, to continuous grinding of the rotor and to overheating.



ROBA-stop®-M brakes are mainly maintenance-free. However, the rotor is subject to operational wear. The friction linings are robust and wear-resistant. This ensures a particularly long service lifetime. If the rotor does become worn due to the high total friction work, and the function of the brake can no longer be guaranteed, the brake can be re-set to its functional state by replacing the rotor. For this, the brake must be cleaned thoroughly. The wear condition of the rotor is determined by measuring the release voltage (this must not exceed max. 90 % of the nominal voltage on a warm brake), or by measuring the rotor thickness on a dismantled brake (“minimum rotor thickness” acc. Table in the currently valid Installation and Operational Instructions). On sizes 500 and 1000 there is an air gap inspection opening. This means that the brake does not have to be dismantled.