Product Overview
The OMSS80 (part number 151F5068) is a core model in the Danfoss OMS Series of short-type orbital hydraulic motors, featuring a Geroler (roller gerotor) gear set with disc valve distribution. This model belongs to the bearingless short motor version of the OMS Series, eliminating the front bearing and output shaft, designed for direct mounting to gearbox or reduction gear input. The OMSS80 has a geometric displacement of 80.5 cm³/rev and forms a complete 80-specification product family with the OMS80 standard version and OMSW80 wheel motor version, all three sharing identical core hydraulic components including the valve mechanism and gear set.
The OMS Series utilizes advanced disc valve Geroler technology, which has rollers incorporated into the internal fixed gear ring, allowing for higher flows and higher pressures than spool valve technology, providing smooth and reliable operation and high efficiency. The series achieves drop-in interchangeability with Eaton Char-Lynn 2000 Series, White WS Series, Parker TF Series, and M+S MLHS/MLS Series. The OMSS80 151F5068 maintains identical mounting flange and port positions with originals for direct replacement without modifying piping or mounting brackets.
Every motor undergoes 100% simulated load testing before shipment, with protocols covering output torque verification at rated pressure, volumetric efficiency measurement at multiple speed points, internal leakage testing, and overspeed validation.
Technical Specifications
Basic Specifications
Model: OMSS80 / OMS80 / OMSW80
Part Number: OMSS80 151F5068
Motor Type: Low Speed High Torque Orbital Motor (Disc Valve Geroler)
Gear Set Type: Geroler (roller gerotor) with rollers in internal fixed gear ring
Valve System: Disc valve with automatic wear compensation
Mounting Flange: 2-Hole Diamond / 4-Hole Diamond (Pilot Ø82.5 mm)
Shaft Type: OMSS80 no output shaft (short motor); OMS80 optional Ø25 mm / Ø32 mm / Ø25.4 mm / Ø31.75 mm cylindrical / Tapered / Splined
Port Size: G1/2 main, G1/4 drain
Seals: NBR standard, FKM optional
OMSS80 / OMS80 Performance Data (80.5 cm³/rev)
Geometric Displacement: 80.5 cm³/rev [4.9 in³/rev]
Max. Speed (Continuous): 800 rpm
Max. Speed (Intermittent): 988 rpm
Max. Pressure Drop (Continuous): 17.5 MPa (175 bar)
Max. Pressure Drop (Intermittent): 21 MPa (210 bar)
Max. Pressure Drop (Peak): 22.5 MPa (225 bar)
Max. Torque (Continuous): 190 N·m
Max. Torque (Intermittent): 240 N·m
Max. Torque (Peak): 260 N·m
Max. Output (Continuous): 15.9 kW
Max. Output (Intermittent): 20.1 kW
Max. Flow (Continuous): 65 L/min
Max. Flow (Intermittent): 80 L/min
Max. Inlet Pressure (Continuous): 25 MPa
Weight: Approx. 9.8 kg
Full OMS Series Displacement Range
OMS80 / OMSS80 / OMSW80: Displacement 80.6 cm³/rev; Speed cont. 800 rpm, int. 988 rpm; Torque cont. 190 N·m, int. 240 N·m, peak 260 N·m; Pressure drop cont. 17.5 MPa; Power cont. 15.9 kW; Weight 9.8 kg
OMS100 / OMSS100 / OMSW100: Displacement 100.8 cm³/rev; Speed cont. 748 rpm, int. 900 rpm; Torque cont. 240 N·m, int. 300 N·m, peak 320 N·m; Pressure drop cont. 17.5 MPa; Power cont. 18.8 kW; Weight 10.0 kg
OMS125 / OMSS125 / OMSW125: Displacement 125.7 cm³/rev; Speed cont. 600 rpm, int. 720 rpm; Torque cont. 310 N·m, int. 370 N·m, peak 400 N·m; Pressure drop cont. 17.5 MPa; Power cont. 19.5 kW; Weight 10.3 kg
OMS160 / OMSS160 / OMSW160: Displacement 157.2 cm³/rev; Speed cont. 470 rpm, int. 560 rpm; Torque cont. 316 N·m, int. 430 N·m, peak 472 N·m; Pressure drop cont. 15 MPa; Power cont. 15.6 kW; Weight 10.7 kg
OMS200 / OMSS200 / OMSW200: Displacement 200.0 cm³/rev; Speed cont. 375 rpm, int. 450 rpm; Torque cont. 400 N·m, int. 466 N·m, peak 650 N·m; Pressure drop cont. 14 MPa; Power cont. 15.7 kW; Weight 11.1 kg
OMS250 / OMSS250 / OMSW250: Displacement 252.0 cm³/rev; Speed cont. 300 rpm, int. 360 rpm; Torque cont. 450 N·m, int. 540 N·m, peak 690 N·m; Pressure drop cont. 12.5 MPa; Power cont. 14.1 kW; Weight 11.6 kg
OMS315 / OMSS315 / OMSW315: Displacement 314.5 cm³/rev; Speed cont. 240 rpm, int. 280 rpm; Torque cont. 560 N·m, int. 658 N·m, peak 740 N·m; Pressure drop cont. 12 MPa; Power cont. 14.1 kW; Weight 12.3 kg
OMS400 / OMSS400 / OMSW400: Displacement 370 cm³/rev; Speed cont. 200 rpm, int. 240 rpm; Torque cont. 536 N·m, int. 645 N·m, peak 751 N·m; Pressure drop cont. 10 MPa; Power cont. 11.8 kW; Weight 12.6 kg
Interchange Reference
Materials & Construction
Housing: High-strength cast iron
Gear Set: Geroler disc valve roller gear set, carburized and hardened alloy steel
Valve Mechanism: Disc valve with automatic wear compensation
Bearings: Tapered roller bearings (OMS/OMSW), high axial & radial load capacity
Seals: NBR standard, high-pressure shaft seal
Key Technical Advantages
1. Disc Valve Geroler Technology with High Volumetric Efficiency
The OMS Series utilizes advanced disc valve Geroler technology, with rollers incorporated into the internal fixed gear ring. Compared to conventional spool valve technology, disc valve distribution allows higher flows and pressures, providing smooth and reliable operation and higher efficiency. The Geroler gear set’s roller pins convert sliding friction at the tooth profile engagement into rolling friction, significantly reducing internal friction losses and wear rates. The valve plate automatically compensates internal clearances based on system pressure, maintaining volumetric efficiency consistently above 90% at 17.5 MPa continuous working pressure. This technology enables the OMS Series to achieve the best combination of high efficiency and economy in medium-duty applications.
2. Engineering Value of OMSS Short Motor Design
The OMSS80 (151F5068) is a bearingless short version of the OMS Series, eliminating the front bearing and output shaft to integrate the hydraulic drive section directly with the gearbox mechanical transmission. The engineering significance is threefold: first, it significantly shortens the motor’s axial installation length for space-constrained equipment; second, it eliminates independent bearing and shaft seal components, reducing system cost and maintenance complexity; third, direct gearbox coupling reduces intermediate links in the drivetrain, improving overall transmission efficiency. This design is particularly suitable for drilling rigs, winches, and other equipment requiring integration of hydraulic drive into existing gearbox systems.
3. Tapered Roller Bearings with High Radial Load Capacity
The standard OMS/OMSW Series output shaft is supported by tapered roller bearings capable of simultaneously accommodating high axial and radial forces. The line-contact load-bearing mode of tapered roller bearings provides significantly higher radial load capacity than ball bearings, suitable for applications involving direct drive of wheels, gears, sprockets, or pulleys. Bearing preload is precisely controlled during assembly to prevent excessive shaft deflection under radial loads, preserving long-term gear mesh precision and shaft seal reliability. The OMSW wheel drive version features reinforced bearing support for higher radial loads in heavy-duty wheel drive systems.
4. Broad Interchangeability and Multi-Platform Compatibility
The OMS Series achieves drop-in interchangeability with Eaton Char-Lynn 2000 Series, White WS Series, Parker TF Series, and M+S MLHS/MLS Series. Mounting flange (2-hole/4-hole diamond flange, Pilot Ø82.5 mm), port positions (G1/2 main, G1/4 drain), and output shaft specifications remain consistent with originals for direct replacement without modifying piping or mounting brackets. The series covers eight continuous displacement sizes from 80 to 400 cm³/rev, providing exceptional selection flexibility for equipment manufacturers.
5. 100% Simulated Load Testing & Batch Consistency
Every OMSS80, OMS Series, and OMSW Series motor undergoes 100% simulated load testing before shipment. Test protocols cover output torque verification at rated pressure, volumetric efficiency measurement at multiple speed points, internal leakage testing, overspeed validation, and noise assessment. All test data is archived and traceable, ensuring each motor’s performance matches its published specifications.
Application Areas
Oil & Gas Drilling Rigs: Rotary table drive (OMSS short motor integrated directly in power head gearbox)
Construction Machinery: Skid steer attachment drives (augers, breakers, sweepers)
Material Handling: Winch drives, conveyor drives
Agricultural Machinery: Combine harvester reel drives, fertilizer spreaders, sprayer pump drives
Municipal Vehicles: Street sweeper brush drives, snow removal equipment drives
Turf Equipment: Commercial mower deck drives, golf course maintenance equipment
Industrial Machinery: Injection molding machine rotary drives, automatic rotary indexing tables
Expert Maintenance Tips
1. Mounting Fit and Bolt Torque
Before installation, verify that the flange spigot (Ø82.5 mm) and machine mounting bore conform to H8/f7 tolerance fit. Tighten mounting bolts in diagonal sequence in 2-3 stages to the specified torque. For the OMSS80 short motor, ensure the spline engagement length between the gearbox input shaft and motor rotor is no less than 80% of total spline length to avoid localized stress concentration. Use G1/2 main ports with recommended tightening torque of 40-50 N·m; G1/4 drain ports at 20-25 N·m.
2. Case Drain Piping
The OMS Series is equipped with a G1/4 case drain port that must be piped separately to the reservoir—never connected in parallel with the main return line. Case drain back pressure should be maintained below 0.5 bar. Periodically inspect drain flow; a significant increase may indicate wear in the shaft seal or valve plate, requiring prompt inspection. The OMSS short motor has no independent case drain port; ensure gearbox internal pressure does not exceed the motor shaft seal’s allowable back pressure rating during installation.
3. System Flushing and Oil Cleanliness
After initial installation or motor replacement, operate at 200-400 rpm under no load for 10-15 minutes to purge air. The OMS Series disc valve orbital motors have high requirements for hydraulic oil quality; system oil cleanliness should meet NAS 9 or ISO 18/15 or better. A 10 μm return-line filter is recommended. Anti-wear hydraulic oil (HM type) with anti-foam and demulsifier additives is recommended, ISO VG 46 or VG 68 grade, with viscosity maintained between 20-75 mm²/s.
4. Storage and Extended Shutdown
For long-term storage, install port plugs to prevent contamination and fill the motor with clean hydraulic oil. Store at temperatures between -20°C and +50°C, away from direct sunlight and moisture. Motors stored for more than 6 months should undergo an internal leakage check before installation.
