90M055NC0N8N0S1W00NNN000020 Danfoss Piston Motor 55cc 450bar

Product Overview

The 90M055NC0N8N0S1W00NNN000020 is a swashplate-type axial piston fixed motor from the Danfoss (formerly Sauer-Danfoss) Series 90 family. Featuring a proven parallel axial piston/slipper design with a fixed swashplate, this fixed-displacement, high-performance axial piston motor is specifically engineered for closed-circuit hydrostatic transmissions.

Series 90 is one of Danfoss’s most classic hydrostatic product lines. The 90M series represents the fixed-displacement version, with maximum displacements ranging from 55 to 130 cm³/rev. The 90M055, as a small-displacement model in the series, delivers 55 cc/rev displacement, with rated working pressure up to 450 bar and peak pressure up to 480 bar. Continuous speed reaches 3900 rpm with intermittent speed up to 4250 rpm.

The 90M055NC0N8N0S1W00NNN000020 features SAE C mounting flange and bi-directional rotation, capable of intaking or discharging fluid through either port. It is widely deployed in hydrostatic travel drive systems for concrete mixer trucks, combine harvesters, rollers, skid steer loaders, and other mobile machinery.

Designed as a 100% interchangeable direct replacement for the original Danfoss Series 90M motor, this product matches OEM specifications in mounting dimensions, porting interfaces, and performance characteristics. Every unit undergoes 100% simulated duty cycle testing prior to shipment, validating volumetric efficiency, mechanical efficiency, and sealing integrity under actual operating load conditions.

Technical Specifications 

• Model: 90M055NC0N8N0S1W00NNN000020

• Brand: Danfoss (formerly Sauer-Danfoss) Series 90

• Product Type: Swashplate Axial Piston Fixed Motor

• Geometric Displacement: 55 cm³/rev

• Max Working Pressure: 450 bar (6,525 psi)

• Peak Pressure: 480 bar (6,960 psi)

• Continuous Speed (at max. disp.): 3900 rpm

• Max Intermittent Speed: 4250 rpm

• Theoretical Torque: 0.88 Nm/bar (530 lbf-in/1000 psi)

• Rated Flow (at max. disp., rated speed): 215 L/min (57 US gal/min)

• Max Flow (at max. disp., max. speed): 234 L/min (62 US gal/min)

• Mounting Flange: SAE C

• Rotation Direction: Bi-directional

• Circuit Type: Closed circuit

• Weight: Approx. 22 kg (SAE flange configuration)

• Optional Features: Loop flushing valve, speed sensor

Key Technical Advantages

1. Swashplate Fixed Displacement Design – High Efficiency and Reliability

The 90M series employs a proven swashplate axial piston architecture with parallel-arranged pistons/slippers and a fixed swashplate. The fixed displacement design eliminates the complexity of variable mechanisms, providing superior reliability and extended maintenance intervals under extreme operating conditions. Volumetric efficiency reaches ≥95%, effectively reducing energy loss.

2. Ultra-High Pressure Rating with Compact Power Density

The 90M055 delivers rated working pressure up to 450 bar and peak pressure up to 480 bar. With a compact 55 cc/rev displacement package, it achieves exceptional power density with maximum continuous power up to 187 kW. This high pressure rating places it among the industry leaders.

3. Wide Speed Range with Bi-Directional Rotation Capability

Continuous speed reaches 3900 rpm with intermittent speed up to 4250 rpm. Bi-directional rotation capability provides flexibility for applications requiring forward/reverse operation. An optional loop flushing valve provides additional cooling and cleaning for closed-circuit applications.

4. 100% Interchangeability – Zero-Modification Drop-In Replacement

Manufactured to exact OEM mounting dimensions, porting specifications, and performance standards, this motor achieves 100% interchangeability with the original Danfoss Series 90M unit. SAE standard mounting flange and SAE threaded port connections ensure convenient installation and excellent interchangeability. No machine modifications are required—simply replace and resume operation, minimizing downtime and reducing maintenance costs.

5. 100% Simulated Duty Cycle Testing for Extreme Environment Reliability

Every motor undergoes 100% simulated duty cycle testing before shipment, validating performance under rated pressure (450 bar) and peak pressure (480 bar) conditions—ensuring long-term reliability in demanding construction, agricultural, and mobile applications.

6. Low-Noise Operation with Extended Service Life

Series 90 motors are renowned for their low-noise operation. Maintenance-free bearings reduce maintenance costs. The compact, lightweight design enables easy integration into various mobile machinery.

7. Modular Configuration for Versatile Application Adaptation

Series 90M offers multiple shaft types (splined, tapered, straight), port configurations, and optional features (flushing valve, speed sensor, etc.). This modular design enables rapid adaptation to concrete mixer trucks, combine harvesters, rollers, skid steer loaders, forestry equipment, turf care machinery, and other diverse applications.

Application Areas

• Concrete Mixer Trucks: Drum hydraulic drives

• Agricultural Equipment: Combine harvesters, beet harvesters, self-propelled sprayer travel drives

• Construction Equipment: Rollers, skid steer loaders, paver travel drives

• Material Handling: Forklift travel drives, AGV drives

• Forestry Machinery: Forwarder travel drives

• Turf Care Equipment: Turf machinery hydraulic drives

• Mining Equipment: Underground auxiliary equipment hydraulic drives

• Specialty Vehicles: Airport ground support equipment, fire ladder truck hydraulic systems

Expert Maintenance Tips

1. Pre-Installation Preparation: Before using the Series 90M motor, read and understand the complete Danfoss instruction manual. For first commissioning, fill the motor housing with hydraulic fluid using a filling unit with filtration not less than 10 µm. Never operate the motor without fluid.

2. Mounting Position: The mounting position can be selected based on actual requirements, but the motor housing must be filled with hydraulic fluid.

3. Independent Braking System: Series 90M motors require an independent braking system—ensure brake oil line connections are correct during installation.

4. Overpressure Protection: An overpressure protection device should be incorporated in the system to prevent the motor from exceeding 480 bar peak pressure.

5. Oil Cleanliness Control: Recommended system filtration not less than ISO 4406 18/13. Regular oil analysis is recommended with filter change intervals adjusted based on contamination levels.

6. Flushing Valve Maintenance (if equipped): For models equipped with flushing valves, regularly inspect the valve’s cracking pressure and flow rate to ensure adequate oil cooling and filtration in the closed circuit.

7. Speed Sensor Inspection (if equipped): For models equipped with speed sensors, regularly inspect the sensor and its connections to ensure accurate and reliable speed signals.

8. Regular Inspection Schedule: Regular inspection of the hydraulic system and motor is recommended. Check hydraulic fluid level daily and monitor operating temperature, noise levels, and case drain flow regularly. Abnormal increases may indicate internal wear or seal degradation.