Schmersal
Sensorless standstill detection of drives
With the 'SSW303HV', the Schmersal Group presents a sensorless standstill monitor that offers significant improvements compared to the predecessor models of the 'AZR' and 'FWS' series - including its universal application options.
The standstill monitor replaces a total of fourteen variants of the previous product range. This is made possible by the use of a wide-range power supply unit for all common operating voltages (direct and alternating current) from 24 V(DC)/ 24 V(AC) to 230 V(AC). The increased temperature range of -25 to +55 °C opens up additional areas of application. Another feature is the compact design: according to Schmersal, the standstill monitor only requires a width of 45 mm in the control cabinet. The plug-in and coded connection terminals create the conditions for quick and error-free installation. An additional signaling contact provides information about the error status of the module.
As the standstill monitor works without sensors, the machine designer does not have to intervene in the 'hardware' of the surrounding construction. The safety module is connected directly to a three-phase AC motor and measures the frequency of the induced voltage directly - for rated motor voltages of up to 690 V. The safety contacts for releasing an interlocking device close as soon as the motor comes to a standstill. The 'SSW 303HV' can be used in safety circuits up to category 4 / performance level e in accordance with EN 13849-1 and SIL 3 in accordance with EN IEC 61508 - with all common types of solenoid interlocks from relevant manufacturers.










