Schneider Electric (Barber Colman) MA-318-303 Actuator

The Schneider Electric (Barber Colman) MA-318-303 Actuator is a heavy-duty 24V spring return actuator engineered for precise two-position control of dampers, valves, and ventilation equipment. Designed mid-stroke for high-torque applications, this oil-immersed motor provides 60 lb-in of torque, ensuring reliable fail-safe operation by returning the controlled device to its original position upon power loss. Housed in a rugged die-cast aluminum enclosure with NEMA Type 4 sealing capability, the MA-318-303 is built to withstand demanding mechanical room environments and industrial configurations.

This model features an integrated SPDT auxiliary switch, allowing for seamless integration with building automation systems or sequence-of-operation signaling. With a standard 180-degree clockwise rotation (90-degree effective travel in specific linkage setups), the MA-318-303 motor utilizes a two-wire control circuit for simplified field wiring. The internal gear train is submerged in oil to minimize friction and thermal wear, maintaining consistent timing and performance across a wide ambient temperature range of -40 to 136°F.

• Fail-Safe Security: Reliable spring return mechanism ensures dampers or valves close or open immediately during power interruptions.
• Enhanced Durability: Oil-immersed gear train and motor provide superior heat dissipation and long-term mechanical reliability.
• System Feedback: Built-in SPDT auxiliary switch enables remote status monitoring or auxiliary equipment interlocking.
• Industrial Construction: NEMA Type 4 rated aluminum housing protects internal components against dust and moisture infiltration.
• Flexible Installation: Coded screw terminals and dual 1/2-inch conduit openings streamline mounting and electrical termination.

What is the primary application for the MA-318-303?
This actuator is specifically designed for two-position (on/off) control of HVAC dampers and valves that require a safety return to a "normal" position if the 24V power supply is cut.

Can this actuator be mounted in any orientation?
While versatile, it is recommended to mount the actuator with the shaft in a horizontal position to ensure the oil-submerged motor maintains proper lubrication around the gear train.

Does the MA-318-303 include an auxiliary switch?
Yes, this specific -303 configuration includes an integrated SPDT switch for end-of-travel signaling or activating secondary devices like fans or pumps.

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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.