In addition to sensorless speed monitoring, the UH 6937 from Dold now also offers safe monitoring of the phase sequence resp. direction of rotation of motors with 3-phase AC voltages. If the motor does not move in the desired direction, the device switches off safely.

The speed and frequency monitor UH 6937 of the SAFEMASTER S series is therefore perfect for applications where the correct direction of rotation is essential, such as in automation processes, compressors, machine tools and wind turbines. The direction of rotation monitoring fulfils PL d / Cat. 2 according to EN ISO 13849-1 and SIL 2 according to EN 61508 while retaining the previous safety-related characteristic data PL e / Cat. 4 and SIL 3 for speed and frequency monitoring.

The device can be operated in a user-friendly way via the four buttons on the front and the LC display, thus enabling simple and time-saving parameterisation – completely without a PC. Up to four operating modes are possible for different configurations of overfrequency, underfrequency, window range and direction of rotation. If the set parameterisation is violated, the frequency monitor switches off dangerous situations in a safety-oriented manner. The UH 6937 from Dold shows its benefits compared to frequency inverters with integrated safety functions when simplicity, flexibility and safety are required.