XPSUVN is a safety relay for interrupting safety-related circuits. XPSUVN enables sensorless standstill monitoring of a motor and measures the residual voltage caused by remanent magnetization after the power supply to the motor has been interrupted and while it is coasting down. The voltage is measured via an analog voltage measurement input to determine when standstill has actually been reached. This can be used to implement a safety-related function, such as controlling an interlocking device with guard locking. The following motor types can be connected to the safety-related input of the device, which generate a measurable residual voltage when coasting down after switching off the supply voltage:

Three-phase AC motors

Single-phase AC motors

DC motors

Three-phase AC motors with star-delta switching

The XPSUVN safety relay can monitor both motors operated from the mains supply and motors controlled by electronic motor control devices such as frequency converters. In addition, it has an adjustable switch-on delay. The turn-on delay is the time between when the measured voltage falls below the set voltage threshold and when the activation of the safety-related outputs is triggered.

The voltage threshold and the activation delay can be configured via selector switches on the front panel. The diagnostic output transmits extensive status information for simplified maintenance and service via a coded telegram to the standard input of a PLC, which processes it further by means of a function block for common control systems. Another semiconductor output provides a message about the switching status. Five front LEDs provide information on the status of the monitoring circuit and help with diagnostics.