1/4 HP, 115V, 1625 RPM, 2-speed blower motor for Coleman Mach RV air conditioners. Double shaft 5-3/4" x 1/2" x 5-3/4". CW lead end rotation. Sleeve bearings, thermally protected. Confirmed direct replacement for A.O. Smith ORV4538, Century 322P708, Coleman 6757A313, Coleman 6757B311, Coleman K55HXJCP-2593, and Coleman N416CCW68A.
The NBK Parts 20455 is a 1/4 HP, 2-speed blower motor built as a direct cross-reference replacement for the A.O. Smith ORV4538 and the Coleman 6757B311 motor used in Coleman Mach RV rooftop air conditioners. When the original motor's low speed stops working, the motor runs hot, or bearings begin to fail, this is the correct replacement part rather than replacing the entire A/C unit or ceiling assembly.
The motor features a double shaft configuration — 5-3/4" on each end with a 1/2" shaft diameter — allowing it to drive both the condenser fan and evaporator blower from a single motor, exactly as configured in the original Coleman unit. Sleeve bearings provide quiet, reliable operation, and thermal protection helps prevent motor burnout from overheating.
This is a semi-enclosed shell design rated for air-over cooling, meaning the motor is designed to be cooled by the airflow generated by the fan blades it drives — standard for this type of rooftop A/C application. Class A insulation is rated for 40°C ambient operating conditions, in line with the demanding rooftop environment these motors operate in.
1625 RPM, 3.1 amps, 115V — matches the original Coleman Mach motor specification exactly
5-3/4" x 1/2" shaft on both ends drives condenser fan and evaporator blower from one motor
Built-in thermal protection helps prevent motor burnout from overheating
Quiet, reliable rotation designed for continuous rooftop A/C duty cycles
Clockwise rotation viewed from the lead end — matches original Coleman motor orientation
Standard frame size for direct fit into existing Coleman motor mounting brackets
• (1) NBK Parts 20455 blower motor
Per NBK Parts' own listing, this motor is a direct replacement for the following part numbers only: • A.O. Smith ORV4538 • Century 322P708 • Coleman 6757A313 • Coleman 6757B311 • Coleman K55HXJCP-2593 • Coleman N416CCW68A Always compare shaft length, diameter, and mounting bracket configuration against your original motor before ordering.