Abstract: An apparatus for testing a speed limiter in an elevator installation includes a drive wheel engaging a cable groove of a cable guide roller in the speed limiter. The drive wheel is rotated by rotational device having a speed control for linearly increasing the speed of rotation of the cable guide roller until the speed limiter is triggered. The rotation of the drive wheel is detected by an evaluating device attached to the rotational device and having an opti-electronic system for generating a light beam toward reflectors on the drive wheel and detecting reflected light beams. The triggering instant of the speed limiter is detected by an acceleration sensor connected to the evaluating device which then calculates the triggering speed from the speed of the drive wheel at the triggering instant.

Abstract: A rotary power transmission system comprises a hydrodynamic speed or torque converter or other fluid coupling in combination with a magnetically actuated friction clutch of simplified construction wherein the friction clutch is accommodated inside the housing of the fluid coupling whereas the magnet for actuating the friction clutch is located outside the housing and the magnetic field generated thereby penetrates through the housing.