405W Winch Drive Planetary Gearbox Reducer

7,000 Nm
Ratios 20 to 80. One housing.

The 4:1 ratio spread means a crane OEM can specify the 405W across an entire product line — from the fast-cycle harbour crane at ratio 20 to the precision offshore auxiliary at ratio 80 — without changing the drum housing, the mounting interface, or the maintenance procedures.

M3-M4: Light Duty

Occasional use, low average load factor. Typical: warehouse overhead cranes used a few times per day, boat yard travel lifts, seasonal agricultural hoists. The 405W is overspecified for these applications — the lighter 400W1 or 401W1 at lower torque is more cost-effective unless the drum torque exceeds their capacity.

M5: Medium-Heavy Duty (405W rated)

Sustained operation at 50-100% load for up to 1 million load cycles over the design life. This covers: mobile cranes on construction sites (100-400 cycles/day), offshore auxiliary cranes (50-200 cycles/day), harbour cranes in moderate-throughput ports. The 405W gears, bearings, and brake are sized for this thermal and fatigue loading.

M6-M8: Heavy to Very Heavy Duty

High-cycle, high-load applications: container terminal quay cranes (500+ cycles/day at near-rated load), steelworks ladle cranes, continuous-process material handling. The 405W at FEM M5 must be derated for these applications — reduce the continuous torque by 15-25% depending on the exact M-class. Or step up to a larger model (406AW at 12,500 Nm) with thermal capacity to sustain the heavier duty cycle at 405W torque levels.

Mobile Construction Cranes (5-15 t SWL)

Rough-terrain cranes, truck-mounted cranes, and crawler cranes in the 5-15 tonne lifting class. The 405W at ratio 25-50 provides the hoisting torque for these machines, while the wide ratio range allows the crane OEM to offer different line speeds (fast-cycle for general construction vs slow-precise for steel erection) using the same gearbox housing. The slewing drive planetary gearbox handles the superstructure rotation, and the wheel drive propels the carrier.

Offshore Auxiliary and Platform Cranes

Pedestal-mounted auxiliary cranes on offshore platforms, FPSOs, and wind turbine installation vessels handling 3-10 tonne cargo transfers. The 405W at ratio 60-80 provides the high brake multiplication (up to 21,600 Nm at the drum) needed for safe load holding during vessel motion, while the sealed, corrosion-resistant housing survives the marine environment. The DNV/Lloyd/ABS classification survey process is simpler with a single well-documented gearbox model than with a bespoke unit — the 405W type approval data package is available on request from Koreas evige magt.

Harbour and Shipyard Cranes

Portal cranes, level-luffing cranes, and shipyard gantry cranes handling 5-12 tonne general cargo at moderate cycle rates (100-300 lifts per shift). The 405W at ratio 20-30 provides the fast hoist speed (30-50 m/min) these cranes need for productive cargo throughput, while the FEM M5 rating covers the sustained duty without overheating. For higher cycle rates approaching container terminal intensity, step up to the 406AW (12,500 Nm) or 406W (13,000 Nm) with greater thermal mass and higher brake capacity.

Why choose the 405W at 7,000 Nm instead of the 405.4W at 5,500 Nm — both cover similar applications?

The 405W provides 27% more torque (7,000 vs 5,500 Nm) with a wider ratio range (20-80 vs 26-57). The 405.4W is physically slightly smaller (125 vs 145 kg) with a slightly higher brake (280 vs 270 Nm). Choose the 405W when the application requires ratios below 26 (fast hoisting) or above 57 (high brake multiplication), or when the 5,500 Nm limit of the 405.4W is too close to the calculated maximum operating torque. Choose the 405.4W when the 20 kg weight saving matters and the ratio range of 26-57 covers the application.

What SWL can the 405W support on a 350 mm PCD drum?

Maximum line pull = torque / PCD radius = 7,000 / 0.175 = 40,000 N = approximately 4,080 kg. This is the bare mechanical capacity on the first cable layer. For a crane certified with a 4:1 structural safety factor, the working SWL = 4,080 / 4 = 1,020 kg on a single-line reeving. With a 4-part line reeving (common for cranes above 5 tonnes), the SWL = 1,020 x 4 = 4,080 kg. Heavier loads require either a larger drum (increasing the PCD) or a higher-torque gearbox.

How does the 4:1 ratio spread affect spare parts inventory for a crane fleet?

The external parts — housing, seals, bearings, brake assembly — are identical across all 405W ratio variants. Only the internal gear sets differ (different tooth counts per stage). A fleet operator running multiple crane models on the 405W platform can stock one seal kit, one bearing set, and one brake disc stack that serves every 405W in the fleet. The gear sets are ratio-specific but rarely need replacement within the design life. This reduces the spare parts holding by approximately 60-70% compared to stocking separate kits for three different gearbox models.

Can the 405W winch drive operate in a free-fall lowering mode for grab crane applications?

Free-fall lowering (releasing the brake and allowing the grab to descend under gravity at uncontrolled speed, then re-engaging the brake to stop) is possible but places severe thermal stress on the brake discs during each stop event. The 270 Nm brake is rated for static holding and occasional emergency stops, not for repeated dynamic decelerations from high speed. For grab crane applications with frequent free-fall cycles (10-30 per hour), specify the 406AW (12,500 Nm, 430 Nm brake) which has greater thermal mass in both the gear set and the brake assembly to handle this severe duty.

What is the oil volume and change interval for the 405W?

Approximately 3-4 litres depending on mounting angle. Use API GL-5 SAE 80W-90 EP gear oil (ISO VG 150 equivalent). First change at 250 hours. Subsequent changes every 2,000 hours in standard crane service or 1,500 hours in dusty, high-temperature, or marine environments. Oil sampling every 1,000 hours is recommended for cranes operating at sustained M5 duty — the 405W thermal capacity is adequate but monitoring oil temperature trends confirms the actual duty is within the design envelope.

Does the winch drive planetary gearbox ratio affect the crane load chart?

Indirectly. The ratio determines the hoisting speed at a given motor speed and flow, and the hoisting speed affects the dynamic load factors used in the crane structural design. A higher ratio produces a slower hoist speed, which reduces the dynamic factors and may allow a slightly higher rated load on the structural analysis. However, the gearbox ratio does not appear directly on the crane load chart — the chart reflects the structural capacity of the boom, the wire rope strength, and the stability moment. The gearbox must simply deliver sufficient torque to lift the load chart capacity at every boom radius.

Standardised the 405W across three rough-terrain crane models: 8 t (ratio 30), 10 t (ratio 45), and 12 t (ratio 65). Before the 405W, we used three different gearbox part numbers from two suppliers with three different seal kits and three different maintenance manuals. Now it is one part number, one spare parts kit, one maintenance procedure. The annual spare parts holding cost dropped by 55%. The 405W runs quieter than the previous units at equivalent speed and the brake engagement consistency across all 120 units delivered so far has been excellent — zero brake holding test failures during our quality incoming inspection.

Auxiliary hoist on a DNV-certified platform crane, 8 t SWL. The 405W type approval documentation was complete and well-structured — the material certificates, gear calculation reports, and brake test data were formatted in a way that our surveyors could verify without requesting supplementary information. The unit passed the factory acceptance test and the onboard commissioning survey in one visit each. From a classification perspective, the 405W is a straightforward approval — the product documentation quality shortened our review cycle by approximately 3 weeks compared to units from other suppliers where we routinely request missing data.

Portal harbour crane, 10 t SWL, 405W at ratio 25. The crane operates at approximately 200 lifts per 8-hour shift handling general cargo. Performance and reliability are good — 11 months in service, oil analysis clean, brake test within spec. The 4-star is a FEM classification observation: our crane operates at the upper boundary of M5 duty intensity (approaching M6 cycle counts). At our current lift rate, we expect to reach the M5 design cycle count approximately 2 years earlier than the originally projected 15-year service life. We are now discussing with Ever-Power whether a torque derating or an earlier overhaul schedule is the better path. Having FEM M5/M6 boundary guidance in the product documentation would have highlighted this consideration during the specification phase.