406AW Winch Drive Planetary Gearbox Reducer

406AW: the explorer

When the crane OEM is developing a new model and the final hoist speed specification is not yet locked — the 406AW covers virtually any speed the prototype testing might require. Also ideal for rental fleet operators who redeploy cranes across different cargo types and hoist speed requirements.

406W: the production standard

When the crane specification is fixed and the ratio requirement falls within 28-140 — the 406W delivers 500 Nm more torque and a proven two-stage architecture at the most common ratios.

406BW3: the heavy-duty specialist

When the application needs 17,500 Nm and the ratio falls within 63-136 — the three-stage 406BW3 provides 40% more torque than the 406AW at the same brake and input speed.

Shipbuilding Block Positioning

Ship sections weighing 5-12 tonnes must be positioned to within 2-5 mm of the weld line during block assembly. At ratio 220, the 406AW provides the creep speed and the motor torque controllability to achieve this precision. Each revolution of the motor shaft translates to only 5.7 mm of cable travel on a 400 mm PCD drum — giving the crane operator effectively infinite positioning resolution through motor speed control alone.

Subsea Equipment Deployment

Lowering subsea manifolds, wellheads, and pipeline end terminations through the splash zone at controlled speed. The wave action at the surface creates dynamic cable tensions that the winch must absorb without jerking the load. At ratio 220, the motor operates at moderate speed (1,000-2,000 rpm) while the drum barely moves — the motor inertia and the gear reduction together act as a mechanical damper against wave-induced load fluctuations. The 430 Nm brake through ratio 220 produces 94,600 Nm of holding torque at the drum — sufficient to hold any load within the 12,500 Nm gearbox capacity on any drum diameter.

Heavy Module Final Placement

Industrial plant construction, bridge erection, and heavy lift operations where the final 50 mm of lowering determines whether a 10-tonne module seats correctly on its foundation bolts. At ratio 220 with a variable-displacement motor reduced to minimum displacement, the winch delivers sub-millimetre-per-second lowering speed. The crane operator can hear and feel the motor response before the load moves visibly — providing an intuitive control feedback loop that fast-ratio winches cannot offer.

Heavy Offshore Platform Cranes (10-25 t SWL)

Main hoist winches on offshore pedestal and knuckle-boom cranes that must handle both fast cargo transfer (ratio 23-60, 25-40 m/min) and slow subsea deployment (ratio 150-220, 2-8 m/min) depending on the operation. The 406AW eliminates the need for a two-speed winch design or a separate auxiliary winch for slow work — one winch drive covers both speed regimes by selecting the appropriate ratio at order. The slewing drive planetary gearbox handles the crane rotation on the same platform.

Shipyard Gantry and Portal Cranes

Shipyard cranes that lift and position hull sections, engine blocks, and superstructure modules ranging from 5-12 tonnes. These cranes need fast hoisting for general lifting (ratio 30-50) and ultra-slow positioning for block assembly (ratio 180-220). The 406AW wide ratio range allows the shipyard to specify a single gearbox model for all yard cranes — fast-cycle units at low ratio and precision units at high ratio — with common spare parts and maintenance procedures across the fleet.

Rental Fleet Multi-Purpose Cranes

Crane rental companies that deploy the same crane across different job types — today lifting precast panels (fast hoist, ratio 30), next week positioning a generator set on vibration mounts (slow precision, ratio 150). The 406AW allows the rental fleet to match the winch drive to the job by selecting ratio at order, then redeploying the crane to different customers without any winch modification. The wheel drive planetary gearbox handles the crane carrier travel for the same rental fleet.

How does the 406AW achieve a 23-220 ratio range when the 406W only spans 28-140?

The 406AW is available in both two-stage and three-stage configurations within the same housing family. The lower ratios (23-80) use a two-stage gear set with large sun gears for high speed. The higher ratios (80-220) use a three-stage gear set with additional planetary reduction. The 406W is a two-stage-only model, which limits its maximum ratio to approximately 140. The 406AW three-stage option extends the ceiling to 220 at the cost of slightly lower efficiency at the highest ratios (93-94% versus 95% for two-stage).

Does the 430 Nm brake provide adequate holding at ratio 23 (the lowest multiplication)?

At ratio 23, the 430 Nm brake produces 9,890 Nm at the drum. On a 400 mm PCD drum: maximum holdable line pull = 9,890 / 0.2 = 49,450 N (approximately 5,040 kg). With a 1.5x safety factor for general cargo: maximum working line pull = 3,360 kg. For loads exceeding this, either increase the ratio (which increases brake multiplication) or add a secondary external brake. At ratio 220, the same 430 Nm brake holds 94,600 Nm — effectively unlimited for any load within the 12,500 Nm gearbox capacity.

Is the 406AW suitable for container terminal quay cranes?

Container terminal quay cranes operate at FEM M6-M8 duty — 500+ cycles per shift at near-rated load. The 406AW at FEM M5 must be derated by 15-25% for this duty, which reduces the effective continuous torque to approximately 9,400-10,600 Nm. If this derated capacity meets the crane design requirement, the 406AW can serve. If the full 12,500 Nm is needed at M6+ duty, step up to the 407 family (18,000-26,000 Nm) which has the thermal mass and bearing capacity for continuous heavy-duty crane service.

What oil volume and maintenance schedule applies to the 406AW?

Approximately 5-7 litres depending on the stage count and mounting angle. Use API GL-5 SAE 80W-90 or ISO VG 150 EP gear oil. First change at 250 hours. Subsequent changes every 2,000 hours in standard crane service or 1,500 hours in marine/offshore environments. Oil sampling every 1,000 hours is recommended. Brake disc inspection every 2,500 hours. Rotary union inspection every 2,500 hours. Contact Korea Ever-Power for the complete maintenance schedule matched to your FEM duty class and operating environment.

Can a winch drive with ratio 220 back-drive under load (will the load lower itself)?

At ratio 220, the friction within the three-stage planetary gear train is high enough that back-driving efficiency (output driving the input) drops below 50%. This means a suspended load cannot turn the motor fast enough to overcome internal friction — the gears resist back-driving. However, this friction-lock is NOT a substitute for the parking brake. Friction varies with temperature, oil viscosity, and wear state, and must never be relied upon for load holding. The 430 Nm spring-applied brake is the designated holding mechanism regardless of the self-locking tendency at high ratios.

How does the winch drive planetary gearbox handle dynamic overloads from wave-induced crane loads?

Wave action on offshore cranes produces dynamic amplification factors of 1.3-2.0 depending on the sea state and the crane tip height. The 406AW rated at 12,500 Nm continuous can sustain peak transient torques of approximately 25,000 Nm (2x rated) for sub-second impulses without gear damage. For sustained dynamic loading in significant wave heights above 2.5 metres, apply a dynamic amplification factor to the steady-state torque and verify that the amplified torque does not exceed the rated capacity. If it does, either reduce the crane rating for the sea state or step up to the 407AW (18,000 Nm) for greater dynamic headroom.

20 t SWL offshore crane, main hoist. We selected the 406AW at ratio 80 for general cargo work (18 m/min at full load) but our client added a subsea deployment requirement during the build phase. With any other gearbox, this would have required a complete winch redesign. With the 406AW, we simply respecified at ratio 190 for the subsea variant — same housing, same drum, same frame, same hydraulic circuit, same classification documentation. The two cranes are mechanically identical except for the internal gear set. Spare parts inventory for both cranes: one kit. This is the product that makes mid-project scope changes survivable.

Shipyard gantry crane, 12 t capacity, block assembly duty. 406AW at ratio 200. The positioning precision at this ratio is remarkable — our welders report that the ship sections arrive within 3 mm of the weld line on first approach, compared to 15-20 mm with our previous fast-ratio winch that required manual chain-block final positioning. The time saving on each block join is approximately 20 minutes (eliminating the chain-block step). Across 400 block joins per vessel: 133 hours saved. At 4 vessels per year: 532 hours of production time recovered. The investment in the 406AW paid for itself during the first hull.

Rental fleet, 8 cranes across 3 job types. The 406AW standardisation reduced our gearbox part numbers from 5 to 1 and eliminated the ratio-mismatch risk that caused two redeployment delays last year (wrong gearbox for the job, 3-week wait for replacement). The 4-star is a logistics observation: the 406AW three-stage variant (ratios above 140) weighs and measures slightly differently from the two-stage variant (ratios below 80), which means the "one part number" advantage has a caveat — the two variants are not dimensionally interchangeable even though they share the same product designation. Making the dimensional differences explicit in the ordering documentation would prevent the assumption that any 406AW fits any 406AW drum.