{"product_id":"abb-cm-srs-21-over-under-current-rms-monitoring-relay-220-240v","title":"ABB CM-SRS.21 Over Under Current RMS Monitoring Relay 220-240V","description":"\u003cdiv\u003e\u003cp\u003eABB CM-SRS.21S Over and Under Current RMS Monitoring Relay is a true RMS measuring device for single-phase circuits that triggers control signals when the monitored current falls outside preset limits, delivering reliable overcurrent and undercurrent protection. It runs on 220–240 V AC (50\/60 Hz), belongs to ABB’s CM-SRS family of measuring and monitoring relays, and provides two changeover contacts (2 c\/o) for signaling and interlock purposes. The current-sense range is 3 mA to 1 A RMS, enabling accurate monitoring across typical loads, and the tripping delay is configurable (0 s or 0.1–30 s) to suit different protection schemes. This relay uses a true RMS measuring principle to maintain accuracy even with non-sinusoidal waveforms and is designed for electrical distribution and machine-control applications where maintaining current within specified limits is critical. Two changeover contacts enable independent signaling or interlocks with other protection devices, aiding integration into standard control circuits.\u003c\/p\u003e\u003c\/div\u003e","brand":"ABB","offers":[{"title":"Used Surplus - Excellent Condition","offer_id":46252458246378,"sku":null,"price":453.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0716\/8039\/3450\/files\/GTG-STOCK-084.png?v=1788727429","url":"https:\/\/gtghardware.com\/products\/abb-cm-srs-21-over-under-current-rms-monitoring-relay-220-240v","provider":"GTG Hardware","version":"1.0","type":"link"}