The Reliance Electric 45C66A is a dual normally open relay output module from the AutoMax/AutoMate series, serving as a revised A-version of the 45C66. It provides two individually isolated high-current relay outputs for driving AC/DC loads in industrial control systems. Designed for rail mounting, it offers reliable electrical isolation and compact construction, suitable for long-term operation in harsh factory environments.

45C denotes the AutoMax/AutoMate series I/O module family. 66 indicates dual normally open relay outputs. The suffix A represents a revised version with minor hardware and labeling updates, functionally interchangeable with the standard 45C66. The full model is used for identification, ordering, and inventory management.

It has two independent normally open output channels with complete electrical isolation between channels. The rated voltage is 250 VAC and 30/110 VDC. The operating voltage range is 1–250 V RMS AC and 1–30 VDC. The maximum load current is 5 A per channel AC (resistive) and 3 A per channel DC. The off-state leakage current is ≤4.6 mA at 125 VAC. It features panel-replaceable fuses and LED indicators for power, channel status, and fuse fault. The operating temperature ranges from -20°C to +60°C, with an IP20 protection class and 45C-series rail mounting.

The module uses a plug-in design that connects to the system backplane for power and signal exchange. It has dedicated screw terminals for external load wiring. Onboard LEDs display power status, individual channel on/off state, and fuse failure. Communication with the main controller occurs via the backplane bus; no additional external communication ports are provided.

It converts internal control logic signals into relay contact switching actions to drive external loads. It provides electrical isolation between the control system and field circuits to suppress noise and prevent damage. A built-in fuse offers overcurrent protection for the module and loads. Status LEDs enable real-time visual diagnostics during operation.

It is widely used in industrial automation systems to drive contactors, solenoid valves, motor starters, and indicator lamps. It suits switching control of 120/230 VAC or 24/48/110 VDC loads on production lines, machine tools, and process equipment. It is ideal for applications requiring medium-current switching and electrical isolation in manufacturing, packaging, and material handling.

Install the module on a compatible 45C rail and ensure full engagement with the backplane. Verify all external wiring is tight before applying power. Regularly inspect LED indicators to confirm correct operation. If a fuse blows, replace it with a 4 A / 250 V AGC-type fuse. Keep the module surface clean and free of dust to maintain proper heat dissipation. Always disconnect system power before removal, inspection, or replacement. Do not disassemble internal components. Replace the entire module if permanent failure occurs.