Littelfuse LSRX Sensor

The Littelfuse LSRX Sensor is a professional-grade, self-powered AC load sensor engineered for contractors who need precise equipment status monitoring without the hassle of external power supplies. This solid-state current sensor utilizes an integrated current transformer (CT) to detect motor operation, effectively serving as a reliable AC current proof relay for fans, pumps, compressors, and industrial mixers. With a fixed trip point of 4.5 Amps, it provides an immediate motor status indicator signal, allowing for seamless interlocking of HVACR components or staging of chillers. The LSRX Series is designed to handle continuous loads up to 200A, utilizing an internal high-current relay output to switch alarm circuits or contactors. This compact unit simplifies installation by combining sensing and switching into a single housing, reducing clutter in the control cabinet and eliminating the need for separate control voltage.

Technical Benefits for Contractors:

• No External Power Required: The unit is fully self-powered by the induction from the monitored line, reducing wiring complexity.
• High Load Capacity: Capable of monitoring conductors carrying up to 200 Amps AC while maintaining a compact footprint.
• Quick-Connect Terminals: Speed up field installation with secure, accessible 1/4 inch male terminals for relay output.
• Visual Diagnostics: An onboard LED provides immediate relay status indication, allowing for rapid troubleshooting of equipment interlocks.
• Universal Mounting: Designed for versatility with integrated tabs for panel mounting or compatibility with DIN rail adapters.

Common Installation Questions:

Does this sensor require a neutral wire or external DC power?
No, the Littelfuse LSRX is strictly self-powered. It draws the energy needed to operate its internal circuitry directly from the electromagnetic field of the AC wire passing through the center hole.

Can I use this to monitor a motor drawing less than 4.5 Amps?
The fixed trip point is 4.5 Amps. For lower amperage loads, you can wrap the conductor through the sensor window multiple times to increase the effective current sensed by the current transformer.

What type of loads can the internal relay switch?
The integrated relay output is rated for switching pilot duty loads, including alarm circuits, small contactor coils, and resistive or inductive control circuits.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.