51303940-251 Dual Fan Alarm Assembly | Honeywell

The 51303940-251 Dual Fan Alarm Assembly is a cabinet cooling and monitoring unit manufactured by Honeywell for TDC and Experion system enclosures. It provides active fan-health surveillance and alarm signaling to maintain thermal reliability within industrial control cabinets, serving as a direct replacement for original UCN cabinet fan assemblies.

Monitoring and Alarm Operation

The assembly features integrated dual-fan monitoring that indicates normal operation via a status LED. Under normal operating conditions, the internal alarm contacts remain closed. When a fan failure is detected, the unit switches to provide a normally-open alarm output at the terminal block.

System Compatibility and Integration

Designed for seamless integration into existing control infrastructure, the monitoring circuit is compatible with standard 24 VDC Digital Input FTAs for remote fan-health monitoring. The unit is available in a CE-compliant 230 V version, and Honeywell recommends installing new replacement fans during maintenance to ensure remaining lifetime reliability.

Frequently Asked Questions

Q: What is the primary function of the 51303940-251 assembly?

A: It provides cabinet cooling support along with integrated fan-health monitoring and alarm signaling for Honeywell TDC and Experion system enclosures.

Q: How does the unit signal a fan failure to the control system?

A: It features a normally-open alarm output at the terminal block and includes a status LED to indicate normal operation of both fans.

Q: What digital input hardware is compatible with this alarm assembly?

A: It is compatible with 24 VDC Digital Input FTAs for remote monitoring of fan health.