90M055 Danfoss Hydraulic Piston Motor 55cc 480bar Fixed

Product Overview

The 90M055 (complete model examples: 90M055NC0N7N0S1W00HNN000020 / 90M055NC0N8N0C6W00NNN0000F0) is a Danfoss/Sauer-Danfoss Series 90 fixed-displacement axial piston hydraulic motor designed for closed-circuit hydrostatic transmissions. Featuring a swashplate design, it delivers high volumetric efficiency and reliable high-pressure performance. This unit offers full dimensional and functional interchangeability with genuine OEM models, matching mounting flange, shaft, ports and overall envelope for direct drop-in replacement. Every unit undergoes 100% simulated operating-condition testing to guarantee consistent performance under high pressure, speed and continuous load. Ideal for demanding mobile applications in construction, agricultural harvesting and compaction equipment.

Technical Specifications 

• Model: 90M055 (typical codes e.g. 90M055NC0N7N0S1W00HNN000020, 90M055NC0N8N0C6W00NNN0000F0 and similar variants)
• Displacement: 55 cm³/rev (approx. 3.35 in³/rev)
• Continuous (rated) working pressure: 450 bar
• Peak pressure: 480 bar
• Continuous speed: 3900 rpm
• Maximum speed: 4250 rpm
• Minimum speed: 500 rpm
• Control: Fixed displacement (speed controlled by flow); optional loop flushing valve, speed sensor, etc.
• Theoretical torque: approx. 0.88 N·m/bar
• Weight (typical SAE flange mount): approx. 22–40 kg (varies by exact configuration and mounting style)
• Mounting: SAE flange (commonly SAE C) or cartridge
• Shaft options: Common S1 splined shaft and others
• Ports: Common twin ports rated to 6000 psi

Data compiled from Danfoss Series 90 official technical information and product specifications. Exact values depend on the specific model code.

Key Technical Advantages

1. Precision swashplate and piston design: High-efficiency axial-piston architecture with precisely machined cylinder block and valve plate delivers high volumetric efficiency and low internal leakage even under high-pressure conditions.
2. High-pressure capability and durability: Continuous 450 bar and peak 480 bar ratings, combined with quality bearings and sealing systems, support prolonged heavy-duty operation.
3. Full interchangeability: Flange, shaft, ports and overall dimensions match genuine Danfoss 90M series units exactly, enabling direct replacement without interface modifications and minimizing downtime.
4. Optimized thermal and contamination management: Optional loop-flushing configuration effectively controls oil temperature and cleanliness, extending fluid and component life; compact, lightweight design reduces machine mass.
5. 100% simulated-condition testing: Every unit is fully tested for pressure, speed, leakage and noise characteristics prior to shipment, ensuring consistent out-of-box performance.

Application Areas

• Hydrostatic travel drives on combine harvesters (e.g. John Deere, Claas series)
• Travel drives on soil compactors and rollers (Bomag, Dynapac, Ammann, etc.)
• Closed-circuit propulsion on bulldozers, excavators, pipelayers, skid-steer loaders and similar construction machinery
• Traction winches, drilling rigs and other applications requiring reliable high-pressure, low-speed, high-torque output

Expert Maintenance Tips

1. Before installation, thoroughly clean the spline shaft and flange face; use correct seals and bolt torque values to avoid misalignment or sealing-surface damage.
2. The system must include independent braking and overpressure protection; maintain proper reservoir, filtration and loop-flushing function to prevent contamination that accelerates valve-plate and piston wear.
3. Fully warm up the system and verify case oil level and low-loop pressure before starting; avoid dry starts or cavitation.
4. Regularly monitor case pressure, leakage rate and noise; when changing fluid and filters, follow recommended viscosity and cleanliness levels.
5. Protect shaft and ports against corrosion during storage; avoid prolonged exposure to moisture or corrosive environments.