90R075A51NN80R3C7D03GBA454528 Danfoss Series 90 Pump 75cc 450bar

Product Overview

The 90R075 / 90R055 / 90R100 / 90R130 / 90L042 / 90L055 / 90L075 series (typical model 90R075A51NN80R3C7D03GBA454528) is a Danfoss (formerly Sauer-Danfoss) Series 90 closed-circuit axial piston variable-displacement pump of cradle swashplate design. Displacement is infinitely variable; flow is proportional to input speed and displacement, and direction is reversed by swivelling the swashplate through neutral. The unit offers 100% drop-in interchangeability with genuine Danfoss pumps—no piping or mounting modifications required. Every unit undergoes full simulated operating-condition testing to guarantee high volumetric efficiency and reliability under high pressure and speed.

Technical Specifications 

• Model: 90R075A51NN80R3C7D03GBA454528 / 90R055 / 90R075 / 90R100 / 90R130 / 90L042 / 90L055 / 90L075 (R = clockwise, L = counterclockwise)
• Geometric displacement: 55 / 75 / 100 / 130 cm³/rev (90R075 / 90L075 = 75 cm³/rev)
• Maximum working pressure: 450 bar
• Maximum pressure: 480 bar
• Rated speed: 3600 rpm (75 cc); 3900 rpm (55 cc); 3300 rpm (100 cc); 3100 rpm (130 cc)
• Maximum speed: 3950 rpm (75 cc); up to 4250 rpm (55 cc)
• Minimum speed: 500 rpm
• Control options: Multiple available (manual displacement control MDC, electro-hydraulic proportional EDC, FNR three-position, hydraulic remote, etc.)
• Weight (with MA control, approx.): 49 kg (75 cc); 40 kg (55 cc); 68 kg (100 cc); 88 kg (130 cc)
• Design features: Closed circuit, integral charge pump, SAE flanges and multiple shaft options, optional through-drive

Key Technical Advantages

1. Precision cradle swashplate and rotary group ensure flow is exactly proportional to speed and displacement, with smooth reversal through neutral, simplifying closed-circuit system design.
2. High volumetric efficiency is maintained in the high-pressure range; maximum working pressure of 450 bar and peak of 480 bar suit high-power propel and work circuits.
3. High-speed capability (rated 3600 rpm for 75 cc) delivers excellent power density in a compact package ideal for mobile equipment.
4. Long-life bearings and wear-resistant materials, combined with modular controls and an integral charge pump, enhance system reliability and response.
5. 100% interchangeability plus full operating-condition testing ensures exact match of mounting dimensions, ports and control characteristics with original Danfoss Series 90 units, minimising downtime.

Application Areas

Designed for closed-circuit hydrostatic transmissions in construction machinery propel drives, agricultural tractors, forestry equipment, road machinery, material handling, oilfield drilling and other mobile or industrial applications requiring high-pressure bidirectional variable flow.

Expert Maintenance Tips

1. Before installation, verify rotation direction (R = clockwise, L = counterclockwise) and shaft spline match; ensure precise flange alignment and avoid radial or axial overloads.
2. Fully bleed the system and check charge pressure (recommended 18–34 bar) before first start-up. Use hydraulic fluid meeting ISO 4406 18/16/13 cleanliness or better.
3. Periodically monitor case pressure (rated ≤3 bar, maximum ≤5 bar) and charge-circuit filter condition; maintain adequate absolute inlet pressure to prevent cavitation.
4. When changing filters and oil, inspect the swashplate, pistons and valve plate for wear. Perform preventive maintenance at the end of design life or when efficiency decreases to maximise hydraulic-system longevity.