When a high-power pneumatic drive is needed without an electric motor, the Cleco MMW421M MM Series radial piston air motor delivers 15 HP with 2,100 RPM free speed for powering machinery such as mixers, conveyors, winches, hoists, and process equipment. Its radial piston design (pistons arranged around a crankshaft to create overlapping power strokes) provides strong torque delivery under load, while the 138 ft-lbs stall torque rating indicates the torque available when the motor is brought to a stop under load.
The MMW421M is a direct-drive, foot-mounted radial piston motor supplied without valving, giving equipment builders and maintenance teams flexibility to pair the motor with the proper external control arrangement for the application. With 1,010 RPM at maximum horsepower, 352 SCFM air consumption, rear exhaust, and a 1-1/4" threaded spindle, this motor is best matched to fixed machinery layouts where air supply capacity, mounting position, and output connection are specified during system design.
Type: Radial Piston Air Motor | Series: MM Series | Model: MMW421M | Maximum Power: 15 HP / 11.19 kW | Free Speed: 2,100 RPM | RPM at Max HP: 1,010 RPM | Stall Torque: 138 ft-lbs / 187 Nm | Air Consumption: 352 SCFM / 9.97 m³/min | Control: Without Valving | Exhaust: Rear Exhaust | Spindle Type: 1-1/4" Threaded Spindle | Mount: Foot Mounting | Gear Ratio: Direct Drive / 1:1 | Air Inlet: 1-1/4" NPTF | Rated Air Pressure: 90 PSI / 620 kPa | Length: 20.42" | Weight: 220 lbs
Features:
- Radial piston motor construction provides strong pneumatic output for machine drive applications where compressed air is the preferred power source.
- 15 HP maximum power supports large mechanical drive requirements in plant equipment, process machinery, and production systems.
- 2,100 RPM free speed allows fast rotation when the driven load and application design require higher shaft speed.
- Direct-drive 1:1 configuration keeps the output path simple without a gear reduction stage.
- Supplied without valving so the motor can be integrated with the external directional or control valve arrangement selected for the equipment.
- 1-1/4" threaded spindle provides a defined output connection point for compatible couplings, adapters, or driven components.
- Foot mounting supports installation on machinery frames, fabricated bases, and fixed equipment platforms.
- Rear exhaust helps route spent air away from the spindle side of the motor during operation.
Made in USA: 
Applications:
- Machine builders and OEM equipment — integrating pneumatic drive power into custom machinery, automated fixtures, and rotating equipment.
- Industrial mixing and agitation — driving mixers, drums, and process equipment where air motors are selected for stall tolerance and variable speed control.
- Conveyors and material handling — powering rotary movement in conveyor sections, transfer equipment, and indexing mechanisms.
- Hoists, winches, and lifting equipment — supplying air-powered rotation for pulling or lifting systems when properly matched to the drive design.
- Plant maintenance and MRO — replacing or specifying air-powered motor drives for existing machinery that operates from a compressed air system.
FAQs:
- Q: What does “without valving” mean on the Cleco MMW421M?
A: It means the motor is supplied without an integral control valve. The installer or equipment designer must provide the appropriate external valve arrangement for the intended operating direction and control method. - Q: What size air system is needed for this motor?
A: The MMW421M is rated at 90 PSI and consumes 352 SCFM. Confirm that the plant air system can supply this flow continuously at the required pressure before installation. - Q: Is the MMW421M a geared air motor?
A: No. This model uses a direct-drive 1:1 arrangement. That keeps output speed high compared with reduction-geared models in the same air motor family. - Q: What does stall torque tell me?
A: Stall torque is the torque available when the motor is braked to a stop under load. For the MMW421M, the 138 ft-lbs stall torque rating helps determine whether the motor has enough overload and starting capability for the driven machine. - Q: Can this motor be used as an electric motor replacement?
A: Yes, in many pneumatic drive systems, but the mounting, spindle connection, speed, torque, duty cycle, and air consumption must be checked against the existing machine requirements before substitution.
| SKU | Mount | Spindle Type | RPM at Max HP | Free Speed | Torque Stall | Weight | Gear Ratio | Length | Horsepower | Air Consumption | Control | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (RPM) | (RPM) | Ft-Lb | Nm | Lb | kg | in | mm | Hp | kW | (SCFM) | |||||
| MMW422M | Foot Mounting | 1 1/4 in Threaded Spindle | 71 | 150 | 1952.0 | 2647 | 231 | 104.8 | 14.2-1 | 20.88 | 530 | 15 | 345 | No Valving |
| MMW423M | Foot Mounting | 1 1/4 in Threaded Spindle | 194 | 400 | 715.0 | 970 | 231 | 104.8 | 5.2-1 | 20.88 | 530 | 15 | 332 | No Valving |
| MMS400M | Foot Mounting | 1 1/4 in Threaded Spindle | 206 | 400 | 715.0 | 970 | 226 | 102.5 | 5.2-1 | 20.88 | 530 | 15 | 336 | Single Direction Valving |
| MMW421M | Foot Mounting | 1 1/4 in Threaded Spindle | 1010 | 2100 | 138.0 | 187 | 214 | 97.1 | 1-1 | 20.42 | 519 | 15 | 352 | No Valving |
| MMS396M | Foot Mounting | 1 1/4 in Threaded Spindle | 1070 | 2100 | 138.0 | 187 | 210 | 95.3 | 1-1 | 20.42 | 519 | 15 | 348 | Single Direction Valving |
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