Siemens Auxiliary Contact Block, 10A, 2NO/2NC - SIRIUS Innovation Series - 3RH2911-1FA22 This auxiliary contact block from Siemens monitors the contactor of a motor to ensure it's running properly. The unit automatically sends a signal to an external control device for quick diagnosis. Simply snap it on the front of the contactor for quick and simple installation. The block is designed for use with contactors, contactor relays and power contactors in the 3RT2 series, making it simple to build a complete setup. You can use this auxiliary contact block for signalling processes in HVAC (heating, ventilation and air conditioning) systems. • Long mechanical service life of 10 million switching cycles for long-lasting performance
• Broad operating temperature range of -25°C to +60°C for use in demanding environments
• Screw terminals for a secure electrical connection
• Current rating of 10A for reduced power consumption
• Surge voltage resistance of 6kV for enhanced electrical safety How reliable is this unit? This unit has a contact reliability rating of one incorrect switching operation per 100 million switching operations, so it's unlikely to fail and will operate reliably throughout its service life.