MDI Mercury Displacement 35NO-24A Contactor

The MDI Mercury Displacement 35NO-24A Contactor is a heavy-duty single pole normally open 24V switching solution designed for high-cycle industrial and HVACR environments. Built for reliability where standard electromechanical relays fail, this 35 amp mercury relay utilizes a liquid mercury contact interface to provide a fresh conduction surface for every cycle. This displacement technology significantly reduces contact pitting and oxidation, making it a preferred choice for HVAC compressor contactor replacements and resistive heating loads. The hermetically sealed stainless steel tube and epoxy encapsulation ensure the internal components remain protected from moisture, dust, and corrosive contaminants common in mechanical rooms.

As a 24VAC coil mercury contactor, this unit integrates seamlessly into standard low-voltage control circuits. Field technicians prioritize this model for its silent operation and ability to handle up to 600VAC on the load side without the need for external heat sinks. When installing the 35NO-24A, ensure it is mounted in a strict vertical position to allow for proper mercury displacement and to avoid intermittent electrical paths. This contactor is engineered for millions of cycles, providing stable performance in demanding refrigeration contactor applications and high-frequency switching tasks.

• Enhanced Durability: Liquid mercury contacts eliminate the mechanical wear and arcing found in traditional silver-pad contactors.
• Hermetic Protection: Gas-filled and vacuum-sealed chamber prevents oxidation and contamination in harsh environments.
• Low Maintenance: Self-renewing contact surfaces maintain low resistance over millions of operations.
• Universal Load Compatibility: Rated for up to 35 amps, suitable for both inductive motor loads and resistive heating elements.
• Superior Thermal Management: Designed to operate in high ambient temperatures without derating or requiring additional cooling.

• Does orientation matter during installation? Yes, mercury displacement relays must be mounted vertically (within 10 degrees) to ensure the mercury pool correctly bridges the electrodes.
• Can this replace a standard 24V definite purpose contactor? Provided the amp rating and pole configuration match, this is a premium upgrade that handles high cycle rates far better than standard units.
• What happens if the internal seal is compromised? The hermetic seal is robust, but if the stainless steel tube is damaged, the unit must be replaced immediately and handled according to hazardous material protocols.

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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.