64418-1X is an industrial electromagnetic relay of Reliance NBR series, custom-designed as dedicated spare component for excitation loop and field loss protection circuit of Reliance legacy DC drives and AutoMax control cabinets. Original manufacturing has been discontinued. Available market stock consists of unused original surplus parts and fully inspected refurbished relays for maintenance replacement on outdated DC drive systems in metallurgical, chemical and papermaking industries. It shares identical mounting dimensions with other derivative models including 64418RW, 64418RS and 64418RD for direct interchangeable field replacement.

64418 is the base part number for Reliance NBR heavy-duty industrial relay platform. The suffix -1X defines fixed coil rating and single contact layout. Digit 1 represents single contact group structure, while letter X indicates factory-specific coil winding revision. Other suffix codes such as RW, RS and RD differentiate coil voltage grades and terminal definitions with unchanged overall mechanical outline.

The relay features a 150VDC rated control coil with nominal power consumption of 12W and matched internal coil component 146-1500. Contact configuration is SPST single-pole single-throw, rated for 1A resistive load at 300VDC with maximum open-contact withstand voltage up to 350VDC. Dielectric withstand voltage between coil winding and contact assembly reaches 2200VAC, and insulation resistance is maintained above 1000 megaohms under standard ambient conditions. Mechanical endurance exceeds 8 million switching cycles, whereas electrical service life under full rated load stands above 80000 operations. Operating ambient temperature ranges from -25℃ to +60℃, storage temperature spans from -40℃ to +85℃, and permissible working relative humidity falls between 5% and 95% under non-condensing environment.

This relay adopts phenolic resin base with metal mounting frame and four screw fixing holes for fixed installation inside drive cabinets. Exposed screw-type copper terminals are reserved on front side for hard-wired field connection without detachable plug-in socket structure. No built-in communication interface is equipped, and all signal connections are completed through hard wiring into drive excitation and interlock control circuits.

The primary function is real-time monitoring of DC motor field winding excitation current. It immediately cuts off main interlock control signal and locks drive output to avoid dangerous motor overspeed once field open-circuit or field-loss fault is detected. In addition, it executes auxiliary logic switching for cabinet auxiliary power circuit and fault feedback signal transmission within Reliance AutoMax control system.

It is mainly installed inside SCR-based Reliance DC drive cabinets equipped on rolling mill equipment, extruder units and papermaking dryer motors across metallurgical, chemical and papermaking sectors. It acts as critical protection component for field-loss interlock safeguard and auxiliary circuit switching of legacy industrial automation equipment.

Disconnect complete cabinet power supply and wait no less than 20 minutes for full residual charge discharge before relay removal or terminal rewiring. Perform quarterly routine maintenance to clear accumulated dust on electromagnetic core with dry compressed air and tighten terminal screws while checking terminals for oxidation. If field-loss alarm occurs on drive without actual field circuit failure, check coil continuity and contact ablation first prior to relay replacement. Prevent transient overvoltage surge from being applied on coil terminals to avoid permanent winding damage.