407W3 Winch Drive Planetary Gearbox Reducer

26,000 Nm

The EP-407W3 marks the boundary where single-motor hydraulic winch drive systems reach their natural limit. Above 26,000 Nm, the motor displacement needed to produce the input torque at practical system pressures exceeds the capacity of most standard axial piston motor frames — and the design transitions to dual-motor configurations or to the larger 410 housing family.

At 26,000 Nm output through ratio 100, the motor input torque is 260 Nm. At 350 bar system pressure (a standard maximum for mobile hydraulics), a fixed-displacement motor needs approximately 470 cc/rev to produce 260 Nm. Variable-displacement motors in this displacement class weigh 80-120 kg and are the largest single-shaft units most motor manufacturers offer. Above this displacement, the catalogue typically transitions to dual-motor packages or to radial piston motors with fundamentally different mounting geometries.

This means the 407W3 at 26,000 Nm is the last torque level where a crane designer can use a single standard axial piston motor driving a single winch drive gearbox through a single input shaft. Above 26,000 Nm — starting with the 410W3 at 37,500 Nm — the practical architecture shifts to either dual motors on a Y-adapter driving one gearbox, or to the larger ZL/ZR winch drive series with high-speed electric motors replacing the hydraulic circuit entirely.

Stay with the 407W3 when:

The calculated drum torque falls within the 26,000 Nm capacity with adequate safety factor. The single-motor hydraulic architecture is preferred for simplicity. The drum housing is already designed for the 407 frame. Weight matters — the 80 kg difference (310 vs 390) affects crane head weight and structural loading.

Step up to the 410W3 when:

The torque requirement exceeds 26,000 Nm at any cable layer. The application needs ratios above 136 (the 410W3 extends to 177). The crane is a new build and the drum can be designed from scratch around the 410 frame. A dual-motor configuration is already planned for other reasons (redundancy, speed range).

Heavy-Lift Offshore Cranes (25-40 t SWL)

Main hoist on offshore heavy-lift cranes handling large subsea structures, drilling equipment modules, and platform deck components. The 407W3 at ratio 100-136 provides the torque for 25-40 tonne lifts on 500-600 mm PCD drums with 8-12 part reeving. The 530 Nm fixed brake delivers up to 72,080 Nm of drum holding torque — sufficient for the most demanding offshore classification requirements. The slewing drive planetary gearbox handles the crane rotation on the same heavy-lift platform.

Large Harbour Portal Cranes

Rail-mounted portal cranes at major ports handling 20-30 tonne general cargo lifts at moderate cycle rates (80-150 lifts per shift). The 407W3 at ratio 80-100 provides the main hoist torque, and the single-motor configuration keeps the hydraulic system compact enough to fit within the portal crane machinery house. For harbour cranes approaching container terminal intensity, the 407W3 FEM M5 rating may require derating — consult 韩国永力 for an M6 duty capacity verification.

Shipyard Main Assembly Cranes

Main hoist mechanisms on shipyard gantry cranes positioning 15-25 tonne hull sections, engine blocks, and superstructure modules. The 407W3 at ratio 100-136 delivers the slow, controlled hoisting that heavy steel positioning demands, while the 530 Nm brake provides the holding margin for loads that may hang suspended for minutes while welders tack the section in place. The wheel drive handles the gantry rail travel on the same crane.

At what ratio does a single axial piston motor become impractical for the 407W3?

Below approximately ratio 90. At ratio 63, the motor input torque is 413 Nm, requiring approximately 740 cc/rev at 350 bar — well beyond standard single-shaft motor catalogues. At ratio 90, the input torque drops to 289 Nm, requiring approximately 520 cc/rev — the upper limit of most variable-displacement axial piston motors. At ratio 136, the input torque is 191 Nm, requiring approximately 345 cc/rev — comfortably within standard motor ranges. For ratios below 90, specify a dual-motor Y-adapter configuration or select the 407AW at 18,000 Nm with its lower ratio range starting at 38.

How does the 407W3 compare to the 406BW3 — both have the same ratio range (63-136)?

Identical ratio range, 48% more torque (26,000 vs 17,500 Nm), larger brake (530 vs 430 Nm), and 40 kg heavier (310 vs 270 kg). The 407W3 uses a larger housing diameter with wider gear faces and heavier bearings. If the drum housing can accommodate the 407 frame, the 407W3 provides a significant capacity upgrade. If the drum is locked to the 406 bolt pattern, the 406BW3 remains the maximum option within that housing. The two models are not interchangeable — different bolt patterns, different shaft diameters, different housing dimensions.

What crane SWL does the 407W3 support with 10-part reeving on a 500 mm PCD drum?

Maximum line pull = 26,000 / 0.25 = 104,000 N. With 10-part reeving: total lifting force = 1,040,000 N. At 4:1 safety factor: SWL = 1,040,000 / (4 x 9.81) = approximately 26,494 kg (26.5 tonnes). With reeving efficiency loss (approximately 2% per sheave, 10 sheaves): effective SWL = 26,494 x 0.82 = approximately 21,725 kg (21.7 tonnes). This is the capacity on the first cable layer — verify at the outermost layer for the crane load chart.

Can the 407W3 serve a dual-hoist crane (main and whip on the same drum)?

Yes, but with limitations. A dual-hoist drum stores both the main hoist cable and a lighter whip hoist cable on the same drum barrel. The 407W3 drives the drum — both cables spool simultaneously. The main hoist operates at full load through the reeving blocks; the whip hoist operates at lighter load on a direct single-line. The challenge is speed: at ratio 100, both cables move at the same drum surface speed, which means the whip hoist (fewer reeving parts) moves the hook much faster than the main hoist. Verify that the whip hoist line speed does not exceed the safe hook approach speed for the intended load.

What is the expected overhaul interval for the 407W3 at heavy offshore crane duty?

At FEM M5 with full maintenance compliance: target first overhaul at 18,000-22,000 hours. Offshore environments accelerate seal wear (salt spray, temperature cycling) and may require seal replacement at 8,000-12,000 hours independent of the gear and bearing condition. Oil changes every 1,500 hours in marine environments. Oil sampling every 500 hours. Brake disc inspection every 2,000 hours. The 530 Nm brake discs typically last 12,000-18,000 hours in offshore crane service. Contact 韩国永力 for a maintenance schedule tailored to the specific crane duty profile and classification society requirements.

Does the winch drive planetary gearbox generate enough noise to affect offshore crane operator comfort?

The 407W3 three-stage gear mesh produces approximately 72-78 dB(A) at 1 metre under full load at typical operating speeds. In an offshore crane cabin — typically 5-8 metres from the winch drum and insulated with acoustic panels — the gearbox contribution to cabin noise is approximately 55-60 dB(A), which is below the 65 dB(A) continuous exposure threshold of most offshore operator comfort standards (NORSOK S-002, ISO 8041). The hydraulic power unit, pump, and cooling fan typically produce more cabin noise than the winch drive gearbox.

40 t SWL subsea crane, main hoist, 407W3 at ratio 120 with a 500 cc/rev variable-displacement motor. The single-motor architecture keeps the crane head weight 95 kg lighter than the dual-motor configuration the previous design used at the same torque level — which recovered 2.3 tonnes of crane structural capacity at maximum boom length. The DNV-GL survey accepted the brake holding calculation at SF = 2.2 on the first review. After 8,000 hours including two major subsea deployment campaigns, oil analysis shows no bearing distress and the brake test results are within 3% of the factory acceptance data.

Shipyard gantry crane, 25 t main hoist, 407W3 at ratio 110. The crane positions engine blocks and stern sections at controlled speed — the welders report consistent first-approach accuracy within 5 mm. We evaluated the 410W3 at 37,500 Nm during the design phase but the 407W3 provided adequate torque margin at 26,000 Nm and saved 80 kg of gantry head weight, which simplified the trolley rail structural design. The 530 Nm brake holds 25-tonne loads in position for up to 30 minutes during tack welding without any drift. Twelve months in service, zero unscheduled maintenance events.

Portal harbour crane, 20 t SWL, 407W3 at ratio 85, approximately 120 lifts per shift. The mechanical performance passes every annual inspection without comment. The 4-star reflects a duty-cycle question that came up during our 3-year statutory inspection: the crane is approaching 15,000 hours at what we now believe is closer to FEM M6 intensity than the original M5 specification. The oil analysis trends are still clean but the bearing vibration baseline has increased by 8% from the commissioning readings — within normal limits but tracking upward. We are now working with Ever-Power on a revised overhaul forecast. For heavy-cycle harbour applications, having a published M5/M6 crossover point based on actual cycle counts per hour would help port engineers like me schedule inspections proactively rather than reactively.