The Marathon B317 Blower Motor is a high-performance 1/2 HP HVAC replacement motor designed for continuous duty in residential and commercial air moving applications. Engineered as a NEMA 56 frame motor, this unit operates at a nominal 1725 RPM (often rated 1800 RPM synchronous speed) and features a versatile 115/208-230V dual voltage capability to match existing field wiring. As a veteran-grade capacitor start induction run motor, it delivers the high starting torque required for heavy blower wheels while maintaining an efficient 8.0/4.1-4.0 Amp draw. The open drip proof (ODP) enclosure ensures maximum airflow for cooling the internal windings during long cycles. Reliability is bolstered by ball bearings and a resilient base mount that significantly dampens vibration and mechanical noise. With selective CCW rotation and a standard 5/8-inch keyed shaft, the B317 provides a direct-fit solution for contractors needing a rugged, single phase blower motor.

Key Benefits

Broad Compatibility: Standard 56 frame size and dual-voltage 115/230V design allow for seamless integration into a wide variety of HVAC cabinets.
Enhanced Durability: Features ball bearings and a sturdy rolled steel frame to withstand the mechanical stress of constant-speed fan applications.
Quiet Operation: The resilient base (cradle mount) effectively isolates motor vibration from the ductwork, reducing decibel levels in the living space.
Internal Protection: Equipped with automatic thermal overload protection to prevent winding failure during high-ambient or restricted-airflow conditions.

Common Questions

What is the shaft size for the Marathon B317?
This motor utilizes a standard 5/8-inch diameter keyed shaft that is approximately 1.88 inches long, making it compatible with most standard blower pulleys and wheels.

Can I use this to replace a 48-frame motor?
The B317 is a 56 frame motor. While it features a 6-1/2 inch diameter, you must verify that your mounting bracket and cabinet clearance can accommodate the larger 56-series frame and resilient base before installation.

How do I change the rotation on this motor?
The B317 is selective CCW rotation from the factory, but the lead configuration can typically be adjusted at the terminal board to match the specific directional requirements of your blower housing.

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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.

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Marathon B317 Blower Motor