OMT500 151B0413 Hydraulic Motor | Danfoss OMS250 151F2205

Product Overview

The OMT and OMS Series hydraulic motors are Danfoss’s (formerly Sauer-Danfoss) classic low-speed high-torque orbital motor families. The OMT Series is positioned for heavy-duty applications with displacements from 160 to 500 cm³/rev, featuring a Geroler gearwheel set and disc valve commutation. The OMS Series is positioned for medium-duty applications with displacements from 80 to 500 cm³/rev, featuring axial porting and a Geroler gearwheel set. Both series deliver high starting torque, constant output torque across a wide speed range, and a high-pressure shaft seal that eliminates the need for an external case drain line.

This product is a drop-in interchange replacement for genuine Danfoss OMT500 (151B0413) and OMS250 (151F2205) hydraulic motors. Mounting flanges, shaft extensions, port configurations, and drain port locations are dimensionally identical to OEM specifications, enabling direct replacement without hydraulic circuit or mounting modification. Every motor is subjected to 100% simulated actual-load testing before shipment, ensuring volumetric efficiency, output torque, and sealing performance meet OEM technical standards.

OEM Part Number Coverage:

• OMT500: 151B0413, 151B3005, 151B2061 and other standard configuration codes

• OMS250: 151F2205, 151F2305, 151F0505, 151F0512 and other standard configuration codes

Technical Specifications (Bulleted List)

OMT500 Technical Specifications:

• Model: OMT500 (OEM Part Numbers: 151B0413 / 151B3005 / 151B2061)

• Geometric displacement: 523.6 cm³/rev (31.95 in³/rev)

• Max continuous pressure differential: 160 bar (2320 PSI)

• Max intermittent pressure differential: 210 bar (3050 PSI)

• Peak pressure: 240 bar (3481 PSI)

• Max continuous torque: 1220 Nm (10798 lbf·in)

• Max intermittent torque: 1370 Nm

• Max continuous speed: 240 rpm

• Max intermittent speed: 285 rpm

• Max continuous power: 26.5 kW (35.5 hp)

• Max continuous flow: 125 L/min (33 gal/min)

• Control type: Fixed displacement, disc valve with valve drive

• Mounting flange: 4-bolt C mount, pilot Ø127.0mm, bolt circle Ø161.9mm, hole Ø14.4mm

• Shaft options: Ø40mm cylindrical keyed / 1-1/2″ 17T splined / 1-3/8″ 6T PTO

• Main ports: G 3/4 BSP or 1-1/16-12 UN SAE O-ring port

• Drain port: G 1/4 BSP or 9/16-18 UNF O-ring port

• Rotation: Bi-directional

• Shaft seal: NBR standard, Fluorocarbon (Viton) optional

• Bearings: Tapered roller bearings, front and rear

• Integral check valve: Standard

• Seal kit part number: 151B0113

• Weight: Approx. 24.7–28.0 kg (depending on shaft and port configuration)

OMS250 Technical Specifications:

• Model: OMS250 (OEM Part Numbers: 151F2205 / 151F2305 / 151F0505 / 151F0512)

• Geometric displacement: 250.0 cm³/rev (15.3 in³/rev)

• Max continuous pressure differential: 200 bar (2900 PSI)

• Max intermittent pressure differential: 250 bar (3625 PSI)

• Peak pressure: 270 bar (3916 PSI)

• Max continuous torque: 720 Nm (6372 lbf·in)

• Max intermittent torque: 870 Nm

• Max continuous speed: 300 rpm

• Max intermittent speed: 360 rpm

• Max continuous power: 14.5 kW (19.4 hp)

• Max intermittent power: 18.0 kW

• Max continuous flow: 75 L/min (20 gal/min)

• Control type: Fixed displacement, axial porting

• Mounting flange: Standard SAE 2-bolt, pilot Ø82.5mm, bolt circle Ø106.4mm

• Shaft options: Ø32mm cylindrical keyed / Ø35mm cylindrical / splined

• Main ports: G 1/2 BSP or 7/8-14 UNF SAE O-ring port

• Drain port: G 1/4 BSP or 7/16-20 UNF O-ring port

• Rotation: Bi-directional

• Shaft seal: High Pressure Shaft (HPS) seal, NBR standard

• Bearings: Double-row angular contact ball bearings, radial and axial load capable

• Integral check valve: Standard (151F2205 configuration)

• Weight: Approx. 9.8–10.5 kg

Key Technical Advantages

1. Geroler Gearwheel Set with High Volumetric Efficiency
Both the OMT and OMS Series utilize Danfoss’s patented Geroler gearwheel set. The stator ring gear and rotor transmit power through rolling engagement, significantly reducing friction compared to conventional fixed-tooth designs. This structure maintains smooth operation and constant output torque across the full speed range, with volumetric efficiency consistently above 90% and smooth torque output even at very low speeds (minimum 10 rpm) without crawling.

2. High Starting Torque with Constant Output Across Wide Speed Range
Featuring disc valve commutation (OMT) and axial porting (OMS), the motors deliver high commutation precision with starting torque exceeding 80% of rated torque. The OMT500 delivers 1220 Nm continuous torque at 240 rpm continuous speed, while the OMS250 delivers 720 Nm continuous torque at 300 rpm. Both series provide constant output torque across the full displacement range with minimal torque ripple, making them ideal for heavy-duty applications requiring frequent start-stop cycles or loaded starts.

3. High-Pressure Shaft Seal — No Case Drain Required
The Danfoss OMT/OMS Series comes standard with a High Pressure Shaft (HPS) seal system providing reliable sealing across the full operating pressure range. This design eliminates the need for an external case drain line or check valves, simplifying hydraulic circuit routing and removing a common failure point. The OMT500 features an integral check valve for enhanced system safety and reliability. Seal materials are available in NBR or Fluorocarbon (Viton) for different hydraulic fluid and temperature requirements.

4. Heavy-Duty Bearing System with High Radial and Axial Load Capacity
The OMT500 output end features front and rear tapered roller bearings that withstand significant radial and axial loads, ensuring output shaft rotational precision and bearing life under heavy-duty conditions. The OMS250 employs double-row angular contact ball bearings with low friction and high mechanical efficiency, also supporting substantial radial and axial loads. Both series utilize Geroler gearwheel sets for long service life under high-pressure operation, suitable for extended continuous operation in demanding conditions.

Application Areas

OMT500 Typical Applications:

• Heavy Construction: Large excavator track drive, rotary drilling rig slewing, heavy vibratory roller drum drive

• Forestry Equipment: Harvester drive, forwarder winch drive

• Marine Deck Machinery: Anchor windlass drive, heavy mooring winch drive

• Mining Equipment: Mine winch drive, drill feed mechanism

• Special Vehicles: Heavy tow truck drive, airport snow blower auger drive

OMS250 Typical Applications:

• Agricultural Machinery: Combine harvester reel drive, baler drive, tractor hydraulic steering assist

• Material Handling: Forklift wheel drive, conveyor drive drum, stacker lift mechanism

• Municipal Vehicles: Street sweeper brush drive, snow removal auger drive

• Industrial Equipment: Winch drive, screw conveyor drive, machine tool coolant pump drive

• Marine & Offshore: Deck winch drive, small anchor windlass drive

Expert Maintenance Tips

Pre-Installation Preparation:
Clean all ports and mounting flanges with lint-free wipes or clean compressed air before installation. Verify O-ring integrity. Torque mounting bolts in a diagonal sequence over 2–3 passes. Recommended torque: 137–150 N·m for OMT500 (M12 bolts); 68–75 N·m for OMS250 (M10 bolts). After installation, manually rotate the output shaft to confirm free and smooth rotation without binding.

System Flushing & Air Bleeding:
Following initial installation or motor replacement, perform a system flush at low pressure (≤30 bar) for a minimum of 30 minutes to remove particulate contamination. Then run the motor at low speed and no load for 15–20 minutes to bleed air from the system. Observe for foam in the reservoir, system noise, or motor crawling — all indicating residual air. Continue bleeding until operation is smooth.

Hydraulic Fluid Management:
Use anti-wear hydraulic oil with ISO VG 46 or ISO VG 68 viscosity grade. Maintain fluid cleanliness at ISO 18/16/13 or NAS Class 8 minimum. Operating temperature should not exceed 80°C continuous; short-term peak up to 95°C is acceptable. Replace hydraulic fluid after the first 50 operating hours, then follow normal maintenance intervals.

Drain Port Management:
If the motor is equipped with a drain port (G 1/4 or 9/16-18 UNF), route the drain line separately back to the reservoir with the end submerged below the oil level. Drain line back pressure should not exceed 2 bar. Both OMT500 and OMS250 feature integral check valves that protect the shaft seal from system back pressure.

Periodic Inspection:
Check volumetric efficiency every 500 operating hours or quarterly. Test method: lock the output shaft at rated pressure and measure leakage flow. If leakage exceeds 10% of rated flow, internal wear has entered an accelerated phase — schedule service or replacement. Also inspect shaft seals for seepage and bearings (tapered roller for OMT500, angular contact ball for OMS250) for abnormal noise or vibration.