{"product_id":"siemens-3ug4511-1aq20-monitoring-relay","title":"Siemens 3UG4511-1AQ20 Monitoring Relay","description":"\u003cdiv\u003e\u003cp\u003eSiemens 3UG4511-1AQ20 is an analog monitoring relay in the 3UG family designed for phase-sequence monitoring in three-phase power networks, with a continuous operating range of 420 to 690 V AC at 50\/60 Hz, making it suitable for high-voltage industrial applications. The unit incorporates a single changeover (SPDT) contact that provides a definitive status output to control logic or interlocks, enabling motor controllers and starters to respond quickly to a misphased condition, while wiring is accomplished via screw terminals for straightforward installation. In Siemens' legacy lineup, 3UG4511-1AP20 covers a lower voltage range (320–500 V) and is documented as having 1 changeover contact, with 3UG5511-1AR20 listed as the recommended successor; the AQ20 version thus represents the higher-voltage variant in this family. Common applications include protecting motors, pumps, and conveyors by verifying correct phase sequence before energization, enabling safe start-up sequences in switchgear and control panels, and providing a simple, reliable interface for PLCs and automation systems that require phase-order confirmation.\u003c\/p\u003e\u003c\/div\u003e","brand":"Siemens","offers":[{"title":"Used Surplus - Excellent Condition","offer_id":46268183871722,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0716\/8039\/3450\/files\/GTG-STOCK-017.png?v=1788727429","url":"https:\/\/gtghardware.com\/products\/siemens-3ug4511-1aq20-monitoring-relay","provider":"GTG Hardware","version":"1.0","type":"link"}