Spring force activated and 
electromagnetically opened Brake callipers

Safety brake; 
pressure is produced by spring force, releasing electromagnetically.

DV 20 FEM    + braking torque 180 - 610 Nm (depends on disk) + for assembling parallel to the disc + extreme low power consumption (15W)  + designed for  230 VAC or 400 VAC + manually adjustment to counter friction block wear