Product Overview
The OMT 315, OMT 400, OMT 500, OMT 630, and OMT 800 are core displacement models in the Danfoss OMT Series of heavy-duty Low Speed High Torque (LSHT) orbital hydraulic motors, covering drop-in interchangeability with BMT/BM4 series equivalents. Featuring an advanced Geroler (roller gerotor) gear set with disc valve distribution, the series covers geometric displacements from 326.3 to 801.8 cm³/rev, with continuous output torques from 950 N·m to 1464 N·m, maximum continuous pressure drops up to 20 MPa, and intermittent pressure capability up to 24 MPa.
The OMT Series utilizes a disc valve distribution system with valve drive, where the valve plate is continuously pressure-loaded against the stator-rotor end face during operation for automatic wear compensation. The output shaft is supported by front and rear tapered roller bearings capable of simultaneously accommodating high combined axial and radial loads, suitable for wheel drives, winch drives, drilling rig power head rotation, and other heavy-duty applications. The motor features standard check valve function with a high-pressure shaft seal design, supporting operation in both open and closed loop hydraulic circuits without an additional drain line under elevated return pressure conditions.
The series achieves drop-in interchangeability with Danfoss OMT/OMTW/OMTS Series, while remaining compatible with Eaton Char-Lynn 6000 Series, M+S MLHT/MLS Series, Parker TF/TG Series, and BMT/BM4/6K/HMT equivalents. Mounting flange (4-bolt square flange, Pilot Ø125 mm, BC Ø160 mm, Hole Ø14 mm), port positions (G 3/4 main, G 1/4 drain), and output shaft specifications (Ø40 mm cylindrical with 12×8×70 mm key) remain consistent 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: OMT 315 / OMT 400 / OMT 500 / OMT 630 / OMT 800
Interchange Models: BMT 315 / BMT 400 / BMT 500 / BMT 630 / BMT 800; BM4 Series
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 valve drive, automatic wear compensation
Mounting Flange: 4-Bolt Square Flange (Pilot Ø125 mm, BC Ø160 mm, Hole Ø14 mm)
Shaft Type: Ø40 mm Cylindrical (A12×8×70 mm key, DIN 6885) / 17T Spline / Tapered
Port Size: G 3/4 main (side port, staggered), G 1/4 drain
Bearings: Front & rear tapered roller bearings (high axial & radial load capacity)
Seals: NBR standard
Check Valve: Standard
Temperature Range: -30°C to +90°C
Recommended Oil Viscosity: 20-75 mm²/s
Max. Inlet Pressure: 210 bar continuous, 250 bar intermittent, 300 bar peak
OMT 315 Performance Data (326.3 cm³/rev)
Geometric Displacement: 326.3 cm³/rev [19.91 in³/rev]
Max. Speed (Continuous): 380 rpm
Max. Speed (Intermittent): 460 rpm
Max. Pressure Drop (Continuous): 20 MPa (200 bar)
Max. Pressure Drop (Intermittent): 24 MPa (240 bar)
Max. Pressure Drop (Peak): 28 MPa (280 bar)
Max. Torque (Continuous): 950 N·m [8410 lbf·in]
Max. Torque (Intermittent): 1140 N·m [10090 lbf·in]
Max. Torque (Peak): 1346 N·m
Max. Output (Continuous): 33.5 kW
Max. Output (Intermittent): 40 kW
Max. Flow (Continuous): 125 L/min
Max. Flow (Intermittent): 150 L/min
Weight: Approx. 21 kg
OMT 400 Performance Data (410.9 cm³/rev)
Geometric Displacement: 410.9 cm³/rev [25.07 in³/rev]
Max. Speed (Continuous): 305 rpm
Max. Speed (Intermittent): 365 rpm
Max. Pressure Drop (Continuous): 18 MPa (180 bar)
Max. Pressure Drop (Intermittent): 21 MPa (210 bar)
Max. Pressure Drop (Peak): 24 MPa (240 bar)
Max. Torque (Continuous): 1080 N·m [9560 lbf·in]
Max. Torque (Intermittent): 1260 N·m [11150 lbf·in]
Max. Torque (Peak): 1450 N·m
Max. Output (Continuous): 30.0 kW
Max. Output (Intermittent): 35.0 kW
Max. Flow (Continuous): 125 L/min
Max. Flow (Intermittent): 150 L/min
Weight: Approx. 22 kg
OMT 500 Performance Data (523.6 cm³/rev)
Geometric Displacement: 523.6 cm³/rev [31.95 in³/rev]
Max. Speed (Continuous): 240 rpm
Max. Speed (Intermittent): 285 rpm
Max. Pressure Drop (Continuous): 16 MPa (160 bar)
Max. Pressure Drop (Intermittent): 18 MPa (180 bar)
Max. Pressure Drop (Peak): 21 MPa (210 bar)
Max. Torque (Continuous): 1220 N·m [10800 lbf·in]
Max. Torque (Intermittent): 1370 N·m [12130 lbf·in]
Max. Torque (Peak): 1644 N·m
Max. Output (Continuous): 26.5 kW
Max. Output (Intermittent): 30.0 kW
Max. Flow (Continuous): 125 L/min
Max. Flow (Intermittent): 150 L/min
Weight: Approx. 23 kg
OMT 630 Performance Data (629.1 cm³/rev)
Geometric Displacement: 629.1 cm³/rev
Max. Speed (Continuous): 196 rpm
Max. Speed (Intermittent): 233 rpm
Max. Pressure Drop (Continuous): 14 MPa (140 bar)
Max. Pressure Drop (Intermittent): 16 MPa (160 bar)
Max. Pressure Drop (Peak): 19 MPa (190 bar)
Max. Torque (Continuous): 1318 N·m
Max. Torque (Intermittent): 1498 N·m
Max. Torque (Peak): 1619 N·m
Max. Output (Continuous): 25.3 kW
Max. Output (Intermittent): 27.5 kW
Max. Flow (Continuous): 125 L/min
Max. Flow (Intermittent): 150 L/min
Weight: Approx. 24 kg
OMT 800 Performance Data (801.8 cm³/rev)
Geometric Displacement: 801.8 cm³/rev
Max. Speed (Continuous): 154 rpm
Max. Speed (Intermittent): 185 rpm
Max. Pressure Drop (Continuous): 12.5 MPa (125 bar)
Max. Pressure Drop (Intermittent): 13 MPa (130 bar)
Max. Pressure Drop (Peak): 15 MPa (150 bar)
Max. Torque (Continuous): 1464 N·m
Max. Torque (Intermittent): 1520 N·m
Max. Torque (Peak): 1665 N·m
Max. Output (Continuous): 22.2 kW
Max. Output (Intermittent): 26.8 kW
Max. Flow (Continuous): 125 L/min
Max. Flow (Intermittent): 150 L/min
Weight: Approx. 25 kg
Full OMT Series Displacement Range
OMT 160: 161.1 cm³/rev, 625 rpm, 470 N·m continuous torque
OMT 200: 201.4 cm³/rev, 625 rpm, 590 N·m continuous torque
OMT 230: 232.5 cm³/rev, 536 rpm, 670 N·m continuous torque
OMT 250: 251.8 cm³/rev, 500 rpm, 730 N·m continuous torque
OMT 315: 326.3 cm³/rev, 380 rpm, 950 N·m continuous torque
OMT 400: 410.9 cm³/rev, 305 rpm, 1080 N·m continuous torque
OMT 500: 523.6 cm³/rev, 240 rpm, 1220 N·m continuous torque
OMT 630: 629.1 cm³/rev, 196 rpm, 1318 N·m continuous torque
OMT 800: 801.8 cm³/rev, 154 rpm, 1464 N·m continuous torque
Interchange Reference
Danfoss OMT / OMTW / OMTS Series
Eaton Char-Lynn 6000 Series (6K-310, 6K-390, 6K-625, 6K-800, 6K-985)
M+S MLHT / MLS Series
Parker TF / TG Series
BMT / BM4 / HMT / BM6 Series
Materials & Construction
Housing: High-strength cast iron
Gear Set: Geroler roller gerotor, carburized and hardened alloy steel
Valve Mechanism: Disc valve with valve drive, automatic wear compensation
Bearings: Front & rear tapered roller bearings, high axial & radial load capacity
Seals: NBR standard, high-pressure shaft seal
Special Features: Standard check valves
Key Technical Advantages
1. Disc Valve Geroler Distribution with Automatic Wear Compensation
The OMT Series utilizes a disc valve Geroler distribution system, with a valve-driven disc plate working in conjunction with a column-embedded stator-rotor set. Rollers incorporated into the internal fixed gear ring convert sliding friction at the tooth profile engagement into rolling friction, significantly reducing internal friction losses and wear rates. The valve plate is continuously pressure-loaded against the stator-rotor end face during operation for automatic wear compensation, maintaining volumetric efficiency consistently above 90% at 20 MPa continuous working pressure drop. The valve drive design enables the distribution mechanism to automatically adjust distribution phasing based on system pressure, maintaining high efficiency at low speeds.
2. Tapered Roller Bearings with High Combined Load Capacity
The output shaft is supported by front and rear 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 wheel hubs, winch drums, gears, or sprockets. Bearing preload is precisely controlled during assembly to prevent excessive shaft deflection under combined loads, preserving long-term gear mesh precision and shaft seal reliability. This design enables OMT Series motors to be used in heavy-duty wheel drive systems and construction machinery travel drives.
3. High-Pressure Shaft Seal with No Case Drain Requirement
The OMT Series is equipped with a high-pressure shaft seal whose innovative design eliminates the need for a case drain (provided return pressure does not exceed the seal rating). The motor features standard check valve function, ensuring shaft seal pressure never exceeds return line pressure. The engineering significance is twofold: first, it simplifies hydraulic circuit layout, reducing installation costs and leak risks; second, it enables flexible motor application in parallel or series circuits, significantly enhancing system integration freedom. This advantage is particularly prominent for space-constrained engineering vehicle wheel drive systems.
4. Broad Interchangeability and Multi-Platform Compatibility
The OMT Series achieves drop-in interchangeability with Danfoss OMT/OMTW/OMTS Series, while remaining compatible with Eaton Char-Lynn 6000 Series, M+S MLHT/MLS Series, Parker TF/TG Series, and BMT/BM4/6K/HMT equivalents. Mounting flange (4-bolt square flange, Pilot Ø125 mm, BC Ø160 mm, Hole Ø14 mm), port positions (G 3/4 main, G 1/4 drain), and output shaft specifications (Ø40 mm cylindrical with 12×8×70 mm key) remain consistent with originals for direct replacement without modifying piping or mounting brackets.
5. 100% Simulated Load Testing & Batch Consistency
Every OMT 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
Construction Machinery: Excavator travel drives, loader travel drives, road roller drives
Oil & Gas Drilling Rigs: Rotary table drive, winch drive, mud pump drive
Coal Mine Drilling Rigs: Power head rotary drive, tunnel drilling rig drive
Water Well Drilling Rigs: Power head drive, horizontal directional drilling rig drive
Agricultural Machinery: Combine harvester travel drives, sugarcane harvester drives, tractor wheel drives
Forestry Equipment: Harvester head feed roller drives, forestry harvester wheel drives
Material Handling: Heavy-duty winch drives, conveyor drives, forklift drives
Marine & Offshore: Marine winches, anchor windlass drives, deck machinery
Expert Maintenance Tips
1. Mounting Fit and Bolt Torque
Before installation, verify that the 4-bolt square flange (Pilot Ø125 mm, BC Ø160 mm, Hole Ø14 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. When the output shaft is a Ø40 mm cylindrical shaft, ensure coupling or hub fit tolerance and keyway clearance meet design requirements, with key size A12×8×70 mm (DIN 6885). Use G 3/4 main ports with recommended tightening torque of 60-70 N·m; G 1/4 drain ports at 25-30 N·m. When the motor is subject to radial loads, ensure the machine mounting base has sufficient rigidity to withstand reaction torque from bearing loads.
2. Case Drain Piping
The OMT Series is equipped with a high-pressure shaft seal and standard check valves. In applications where system return pressure does not exceed the seal rating, no independent case drain line is required. However, in high-pressure or high back-pressure applications where return pressure exceeds the seal rating, a case drain line is recommended. The case drain 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 shutdown and inspection.
3. System Flushing and Oil Cleanliness
After initial installation or motor replacement, operate at 100-200 rpm under no load for 10-15 minutes to purge air. System oil cleanliness should meet NAS 9 or ISO 18/15 or better. A 10 μm return-line filter is recommended. Hydraulic oils with anti-wear, anti-foam, and demulsifier additives are recommended, ISO VG 46 or VG 68 grade, with viscosity maintained between 20-75 mm²/s. For OMT 630 and OMT 800 large displacement models, flushing flow should reach at least 1.5 times the motor’s rated flow.
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 -30°C and +90°C, away from direct sunlight and moisture. Motors stored for more than 6 months should undergo an internal leakage check before installation. For cylindrical and splined shaft models, pay particular attention to protecting the shaft end and keyway during storage—apply anti-rust grease to the shaft and keyway surfaces.
