ZL55 Winch Drive Planetary Gearbox — 1-5 Stage

Heavy Electric Offshore Cranes (30-50 t SWL)

Next-generation all-electric offshore platform cranes and construction vessel cranes where the torque requirement exceeds the ZL45 capacity but falls below the 4xxW mega-class threshold. The ZL55 at ratio 60-150, 2-3 stage, paired with 300-600 kW electric motors fills this gap — delivering heavy-lift torque with electric-era benefits. The slewing drive handles the crane rotation on the same all-electric vessel platform.

Electric Mining Main Auxiliary Hoists

Heavy auxiliary winders at mines where the auxiliary hoist handles equipment, materials, and heavy consumables that exceed the capacity of smaller auxiliary winches. The ZL55 at ratio 150-400, 3-4 stage, provides the torque for 10-20 tonne auxiliary loads at shaft depths of 300-800 metres. The 5-stage option at ratio 800-2,190 serves ultra-slow precision lowering of sensitive equipment — transformers, ventilation fans, drill rigs — where the descent must be controlled to within centimetres per second.

Heavy Industrial Electric Overhead Cranes

Electric overhead travelling cranes in steelworks, power stations, and heavy manufacturing handling 20-40 tonne loads at moderate to high cycle rates. The ZL55 at ratio 60-120 provides the hoist torque, and the 112,000 Nm peak absorbs the shock loads from heavy-load engagement — ladle attachment, mould clamping, and furnace-door handling — that generate transient torques approaching 2x continuous. The helical gears produce noise levels acceptable inside enclosed industrial buildings.

Why does the 5-stage option appear at the ZL55 and not at the ZL30?

The ZL55 housing diameter is large enough to accommodate the axial length of five planetary stages without the housing wall thickness becoming structurally marginal. On the smaller ZL30/35/45 housings, adding a fifth stage would either require an impractically long housing (exceeding the drum cavity depth of most winch applications) or require thinner housing walls that reduce the torsional rigidity below the design target. The ZL55 housing diameter provides sufficient cross-section to carry five stages at full torque with adequate housing stiffness.

What is the thermal power limit at 5 stages and how does it affect motor selection?

At 5 stages: Pt is approximately 24 kW without external cooling. This means the maximum continuous motor power at 5-stage ratios (800-2,190) is 24 kW in still air at 20 deg C ambient. With an external oil cooler (+50-100%): Pt rises to 36-48 kW. Most 5-stage applications are low-speed precision operations where the motor power is naturally low (15-50 kW servo motors for instrument deployment), so the 24 kW limit is rarely the constraint. For high-power 5-stage applications (mining equipment lowering at high speed through a high ratio), always specify an external cooler.

How does the ZL55 fill the gap between the 4xxW 413W3 and 414W3?

The 4xxW catalogue jumps from 42,500 Nm (413W3) to 140,000 Nm (414W3) — a 97,500 Nm gap. The ZL55 at 55,000 Nm, followed by the ZL75 at 70,000 Nm, ZL85 at 88,000 Nm, and ZL95 at 115,000 Nm, fills this gap with four electric-drive models at torque increments that match the granularity of the lower 4xxW range. These intermediate torque levels serve electric cranes and winches that need more than the 413W3 but not the mega-class engineering of the 414W3.

Does the ZL55 share any components with the ZL45?

The sealing components (FKM lip seals, O-rings) may share dimensions at some shaft positions, and the IP67+ sealing philosophy is identical. However, the internal gear sets, bearings, carriers, and housing castings are size-specific to the ZL55. The ZL55 gear module is larger than the ZL45 to carry the higher torque, which means the tooth counts, planet diameters, and carrier pin dimensions are all different. For fleet spare parts planning, treat each ZL model as an independent product family with its own spare parts inventory.

At 2.04:1 peak-to-continuous, does the ZL55 still offer a meaningful advantage over the 4xxW series for shock loads?

Yes, because the absolute peak headroom matters more than the ratio. The ZL55 provides 112,000 - 55,000 = 57,000 Nm of headroom above continuous. The 413W3 at 42,500 Nm x 2.0 = 85,000 Nm peak, with 42,500 Nm of headroom. The ZL55 provides 34% more absolute headroom (57,000 vs 42,500 Nm) even though the proportional ratio is similar. For grab crane impacts that produce fixed-magnitude torque spikes (not proportional to the continuous rating), the ZL55 absolute headroom is still meaningfully larger.

What axial length does the 5-stage ZL55 add compared to the 3-stage?

Approximately 130-170 mm. Each additional stage adds 65-85 mm depending on the specific gear set width. A 3-stage ZL55 at ratio 150 is approximately 350-400 mm long. A 5-stage ZL55 at ratio 2,190 is approximately 480-570 mm long. This additional length must be accommodated within the drum cavity — verify the available drum depth before specifying 5 stages. For drums designed around 4-stage or 3-stage gearboxes, the 5-stage option may not fit without drum modification. Contact كوريا قوة دائمة for exact dimensional data at your specific ratio and stage count.

40 t all-electric offshore construction vessel crane, main hoist, ZL55 at ratio 100, 3-stage, 500 kW PMSM motor. The ZL55 replaced our standard 413W3 hydraulic specification for the prototype electric crane. The crane completed its classification survey in 8 weeks — faster than any previous hydraulic crane of this class. The 112,000 Nm peak absorbed the test-load drops (required by the classification surveyor) without any VFD fault. Noise at the operator station during full-load hoisting: 54 dB(A). The vessel builder has ordered 4 additional ZL55 units for the next electric offshore vessel in the series.

Heavy auxiliary winder at a 620-metre nickel mine, ZL55 at ratio 250, 4-stage, 200 kW AC motor with VFD. The winder handles 12-tonne equipment loads — drill rigs, ventilation fans, pumps — that the mine's previous 30 kW auxiliary hoist could not manage, requiring the main production winder to handle oversized equipment and losing production winding time. The ZL55 separated the heavy equipment duty from the production cycle, recovering approximately 4 hours of production winding per week. The regen braking during equipment descent returns energy to the mine grid — measured at 31 kWh per descent cycle for a 12-tonne load from surface to the 620-metre level.

Deep-ocean coring winch on a research vessel, ZL55 at ratio 1,800, 5-stage, 20 kW servo motor. The winch deploys a 3-tonne gravity corer to 5,500 metres at 0.9 m/min controlled descent — the slowest deployment speed we have achieved with any winch system outside a purpose-built scientific deep-sea rig. Depth accuracy at touchdown: 0.4 metres at 5,500 m, measured by ship-mounted acoustic positioning. The 5-stage gearbox keeps the motor at 1,620 rpm during descent — well within its efficient torque band — instead of requiring the VFD to crawl at 30 rpm where the motor overheats. The 4-star is a weight observation: the 5-stage housing is approximately 150 mm longer than the 3-stage we initially dimensioned the drum for. We modified the drum, but the additional length was not in the initial specification — it should be prominently stated on the 5-stage data sheet.