407AW Winch Drive Planetary Gearbox Reducer

430 Nm — Standard Hold

Produces 16,340-58,480 Nm at the drum across the ratio range. Adequate for general cargo cranes where the brake safety factor requirement is 1.5x the maximum suspended load. Provides a lighter spring pack, lower brake release pressure (22-28 bar), and longer brake disc life because the clamping force per disc is lower. The 430 Nm option shares brake components with the 406 family — simplifying spare parts if the fleet includes both 406 and 407AW units.

530 Nm — Enhanced Hold

Produces 20,140-72,080 Nm at the drum — 23% more holding capacity than the 430 Nm option at every ratio point. Required for applications where the classification society mandates a 2.0x or higher brake safety factor: offshore cranes with over-water personnel transfer, cranes operating in zone 2 explosive atmospheres, and any winch where the applicable standard demands enhanced brake holding as a condition of certification.

406BW3: maximum torque from the 406 housing

The 406BW3 pushes the 406 housing diameter to its structural limit at 17,500 Nm through three stages. Choose it when the drum housing is already designed around the 406 bolt pattern and cannot accommodate a larger unit. The 406BW3 is a drop-in upgrade for any crane currently using a 406AW or 406W.

407AW: the larger housing frame begins

The 407AW uses a larger housing diameter with heavier bearings and wider gears. At 18,000 Nm it delivers only 500 Nm more than the 406BW3, but with 30% more bearing capacity, 20% more thermal mass, and the selectable brake option. Choose it for new-build cranes where the drum can be designed from scratch around the 407 housing, or when the application needs the 530 Nm brake option that the 406 family cannot provide.

407W3: the heavy-duty ceiling

The 407W3 uses the 407 housing at maximum three-stage capacity: 26,000 Nm with a fixed 530 Nm brake. Choose it when the torque requirement exceeds the 407AW rating and the ratio falls within the 407W3 range of 63-136. Above 26,000 Nm, the catalogue transitions to the 410 family (37,500 Nm) with a different housing frame entirely.

Heavy Offshore Platform Cranes (15-25 t SWL)

Main hoist on offshore cranes handling heavy subsea equipment, drilling consumables, and BOP components. The 530 Nm brake option provides the enhanced safety factor that DNV and Lloyd require for cranes performing lifts over personnel decks or critical equipment. The 407AW at ratio 60-100 delivers the hoist speed for productive cargo throughput while the selectable brake allows the crane OEM to match the certification requirement precisely — 430 Nm for standard cargo zones, 530 Nm for personnel and critical-zone operations — without changing the gearbox model.

Large Construction Tower Cranes

Main hoist mechanisms on large-capacity flat-top and luffing-jib tower cranes with maximum loads of 15-25 tonnes. The 407AW at ratio 80-136 provides the torque for heavy-load lifting at outer radius, and the 430 Nm brake is typically sufficient for construction crane standards (EN 14439). The slewing drive handles the crane rotation, and the wheel drive propels the trolley travel on the jib.

Container Feeder and Multi-Purpose Vessel Cranes

Ship-mounted cranes on container feeder vessels and multi-purpose cargo ships that handle 20-foot containers (up to 24 tonnes gross) in ports without shore cranes. The 407AW at ratio 40-60 provides the fast cycle speeds (30-45 m/min) these cranes need for competitive port turnaround. The 530 Nm brake option is specified when the vessel classification requires enhanced brake hold for operations in sea states above 1.5 m significant wave height — where dynamic load amplification increases the brake demand beyond the 430 Nm capacity.

Can the brake be changed from 430 to 530 Nm in the field after delivery?

Technically possible but not a field operation. The brake torque difference is achieved by changing the Belleville spring stack — the 530 Nm option uses more springs or stiffer springs than the 430 Nm option. Changing the spring stack requires partial gearbox disassembly, spring replacement, brake piston re-assembly, and a brake torque verification test. This is a workshop procedure, not a site procedure. If there is any possibility that the application may require the higher brake in future, specify 530 Nm at order.

Does the 530 Nm brake require higher hydraulic release pressure than the 430 Nm option?

Yes. The stronger spring pack requires approximately 30-38 bar to fully release versus 22-28 bar for the 430 Nm option. Verify that the crane hydraulic pilot circuit can supply this pressure before specifying the 530 Nm brake. On some older crane platforms with 25-bar pilot circuits, the 530 Nm option may not fully release — resulting in brake drag, disc overheating, and accelerated wear. Contact कोरिया एवर-पावर for the exact release pressure specification at both brake options.

Why does the 407AW ratio range start at 38 instead of 23 like the 406AW?

The 407 housing uses larger gears with a larger minimum sun gear diameter than the 406. Larger sun gears produce higher minimum ratios per stage. At two stages, the 407AW minimum achievable ratio is 38 — the gear geometry cannot produce a lower ratio within the 407 housing diameter without reducing the sun gear below its minimum tooth count. If ratios below 38 are required at the 18,000 Nm torque level, the 406AW at ratio 23 comes closest (at 12,500 Nm), or the motor speed can be increased toward 3,500 rpm to achieve equivalent drum speed at the higher ratio.

How does the 407AW compare to the 406BW3 for a crane currently using a 406W?

The 406BW3 (17,500 Nm) is a direct drop-in upgrade for any 406-family drum housing — same bolt pattern, same housing diameter, same output shaft. The 407AW (18,000 Nm) requires a new drum housing designed for the larger 407 bolt pattern and housing diameter. If the existing drum can accommodate both, the 407AW provides 500 Nm more torque, 30% greater bearing capacity, the selectable brake option, and a wider ratio range. If the drum is fixed, the 406BW3 is the maximum upgrade within the existing housing.

What SWL does the 407AW support on a 500 mm PCD drum with 6-part reeving?

Maximum line pull at drum = 18,000 / 0.25 = 72,000 N. With 6-part reeving: total lifting force = 72,000 x 6 = 432,000 N. With a 4:1 structural safety factor: SWL = 432,000 / (4 x 9.81) = approximately 11,009 kg (11.0 tonnes). This is the capacity on the first cable layer. On the outermost layer (larger PCD), the line pull decreases proportionally — verify the capacity at the maximum wrapped diameter for the crane load chart.

Does the winch drive planetary gearbox require different maintenance for the 430 vs 530 Nm brake?

The maintenance procedures are identical — same oil change interval, same seal inspection, same brake disc inspection. The only difference is the brake disc wear rate: the 530 Nm option exerts higher clamping force per engagement, which produces slightly faster disc wear. Expect 10-15% shorter disc life on the 530 Nm option compared to the 430 Nm at equivalent cycle rates. The disc inspection interval remains the same (2,500 hours for general cargo, 1,500 hours for grab duty), but the replacement threshold may be reached 10-15% sooner. Both options use the same disc dimensions — only the spring stack differs.

20 t SWL platform crane, 407AW with 530 Nm brake, ratio 75. The selectable brake was the feature that decided the specification. Our DNV-GL survey required a brake safety factor of 2.0 for lifts over the personnel deck. The 406 family 430 Nm brake at this ratio and drum diameter gave us SF = 1.7 — compliant at 1.5x but not at 2.0x. The 407AW 530 Nm brake gave us SF = 2.1. Without the 530 option, we would have needed to add an external secondary brake — adding cost, weight, hydraulic complexity, and a separate maintenance item. The 407AW solved the certification in one component.

Main hoist on a 20 t luffing-jib tower crane, 407AW with 430 Nm brake, ratio 100. The 430 Nm option was adequate for EN 14439 compliance and kept the brake release pressure within our existing 25-bar pilot circuit — the 530 Nm option would have required upgrading the pilot circuit to 38 bar, which cascades into pump changes, hose upgrades, and re-certification of the entire hydraulic system. Choosing 430 instead of 530 saved approximately EUR 8,000 per crane in hydraulic system modifications across our 60-unit annual production. The 407AW ability to specify the brake precisely matched our needs and avoided unnecessary over-engineering.

Ship-mounted crane on a 700 TEU container feeder, 407AW with 530 Nm brake, ratio 45. The crane handles 20-foot containers at 35 m/min in ports without shore cranes. Hoisting speed and load control are excellent — the operators transitioned from the previous crane model without retraining. The 4-star is a fleet management observation: we ordered 6 cranes for 3 vessels. Two with 430 Nm and four with 530 Nm based on different route classifications. The brake spring stacks are now mixed across the fleet spare parts inventory, and our maintenance team has raised the risk of installing a 430 spring stack into a crane that requires 530. Colour-coding or physical keying of the spring stacks to prevent mis-installation would eliminate this risk.