Product Introduction
The SEW-EURODRIVE ML3PHF120 is an industrial-grade, three-stage helical gear unit specifically designed to meet the rigorous demands of heavy-duty engineering applications. Engineered with a robust, rigid cast iron housing, this unit ensures exceptional structural stability and precise gear alignment under extreme operational loads.
Featuring a specialized hollow shaft output with a shrink disc mechanism, the ML3PHF120 provides a reliable, backlash-free mechanical connection directly to the driven machine shaft. This design eliminates the need for flexible couplings, reducing both the overall physical footprint and maintenance overhead. The three-stage helical gearing is optimized using advanced surface hardening and grinding technologies, maximizing power density while minimizing acoustic emission and thermal losses during continuous high-power transmission.
Technical Specifications
| Technical Parameter | Specification Value | |
| Rated Nominal Power ($P_n$) | 250 kW | |
| Frame Size | 120 | |
| Gear Stages | 3-stage helical transmission | |
| Output Shaft Style | Hollow shaft with shrink disc connection | |
| Housing Material | High-grade grey cast iron (GG25 / GJL250) | |
| Lubrication Type | Splash lubrication (Optional: Forced pressure lubrication via shaft-driven pump) | |
| Cooling System Options | Built-in cooling coil, external oil/air cooler, or radial fan | |
| Thermal Rating Enhancement | Optimized housing geometry for high passive heat dissipation | |
Distinctive Product Features
Bulk Material Handling: Heavy-duty overland belt conveyor drives and continuous bucket elevator systems.
Mining and Minerals: Primary processing crushers, apron feeders, and raw material mill drives.
Pulp and Paper Industry: Agitator drives, pulper transmission units, and heavy industrial drying rollers.
Chemical Processing: Large-scale industrial mixing vessels and fluid aeration systems.
System Integration & Accessories
Auxiliary Cooling and Conditioning Modules
To maintain optimal oil viscosity during high-duty cycles, the ML3PHF120 can be equipped with a direct-mounted mechanical oil pump (type ONP) or an electrical motor pump station. This configuration is often paired with an integrated PT100 temperature sensor and a dual-element oil filter to ensure continuous filtration and monitoring.
Combined Drive Solutions
For processes requiring a controlled startup or precise positioning, the ML3PHF120 integrates directly with the following standard components:
V-belt pre-stages mounted on an integrated motor scooter or swing base.
Hydraulic centrifugal fluid couplings positioned between the 250 kW prime mover and the input shaft.
Electromechanical backstops to prevent reverse rotation in inclined material transport.
RELATED MODEL PARAMETER TABLE
| Model Reference | Gear Train Type | Connection Type | Mounting Layout | Target Rating (250 kW Context) | |
| ML3PHF120 | 3-Stage Helical | Hollow Shaft | Foot Mounted | Baseline Reference | |
| ML3PVF120 | 3-Stage Helical | Hollow Shaft | Vertical Mounted | Identical torque, vertical oil management | |
| ML3PHS120 | 3-Stage Helical | Solid Shaft | Foot Mounted | Requires flexible low-speed coupling | |
| ML4PHF120 | 4-Stage Helical | Hollow Shaft | Foot Mounted | Higher ratio range (i > 80), reduced output RPM | |
| ML3PHF130 | 3-Stage Helical | Hollow Shaft | Foot Mounted | Upsized frame for higher thermal limits | |
Industry Applications
Bulk Material Conveying: Main drive setups for long-distance overland belt conveyors and vertical bucket elevators.
Mining & Aggregates: High-torque mixing vessels, flotation cells, slurry thickeners, and heavy feeder drives.
Pulp & Paper Processing: Primary drives for hydrapulpers, continuous waste agitators, and drying drum sections.
Environmental & Waste: Large-scale water treatment aeration drives and industrial recycling shredders.
FAQ
Q: What is the advantage of the hollow shaft with a shrink disc (ML3PHF) over a standard solid shaft (ML3PSF)?
A: The hollow shaft with a shrink disc provides a keyless, high-torque friction connection directly onto the driven machine shaft. This setup eliminates the risk of keyway wear, simplifies installation and removal, and protects the interface from fretting corrosion over extended service intervals.
Q: What are the standard cooling options available for a 250kW input rating on this size?
A: Depending on ambient conditions and thermal load calculations, the unit can be configured with an internal water cooling coil, a shaft-mounted radial cooling fan, or an external oil-to-water/oil-to-air heat exchanger system to maintain steady-state operational temperatures.
Q: Can the ML3PHF120 be mounted in a vertical position?
A: The standard ML3PHF120 designation is designed for horizontal mounting positions. For vertical installations, a modified lubrication layout (such as a drywell design with forced lubrication) is required to ensure upper bearing arrays receive adequate oil flow.
Q: What parameters determine the exact selection of the nominal gear ratio (i) within the stated range?
A: The specific gear ratio selection is determined by matching the input motor speed (typically 1500 rpm or 1000 rpm at 50Hz/60Hz) with the target operational output speed required by the driven application, while maintaining an appropriate service factor (fB).
Q: How is backsliding prevented in inclined conveyor applications using this gearbox?
A: The ML3PHF120 can be factory-equipped with an internal mechanical backstop module. This component is integrated directly into the intermediate gear stage or input shaft assembly, safely locking rotation in one direction without increasing the external footprint.
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