ZL200 Winch Drive Planetary Gearbox

At 175,000 Nm through ratio 80, the input shaft torque is 2,188 Nm at 5,000 rpm. This approaches the torsional fatigue limit of the input shaft diameter that the ZL200 housing bore can accommodate. Larger input torques would require a larger shaft, a larger housing bore, and a larger housing casting — stepping into a new product platform that does not yet exist in the ZL catalogue. The ZL200 represents the maximum torque that the current ZL housing platform can transmit at 5,000 rpm input.

At 5,000 rpm with the ZL200 first-stage gear module, the tooth peripheral velocity is at the upper limit for carburised 20CrMnTi at DIN 5-6 accuracy. Higher torque would require a larger gear module, which at 5,000 rpm would exceed the safe peripheral velocity and risk lubricant film breakdown at the tooth contacts. The ZL200 sits at the intersection of the maximum gear module size and the maximum input speed — any increase in either parameter would push the other beyond its limit.

For applications exceeding 175,000 Nm continuous from an electric platform, three paths exist: (1) dual ZL200 units through a torque-combining gearbox — producing up to 350,000 Nm continuous, (2) the ZR right-angle winch drive series — a different architecture with right-angle input that can accept larger electric motors, or (3) the 4xxW mega-class for sustained duty above 175,000 Nm where the hydraulic infrastructure already exists. Contact Corea Ever-Power for multi-unit and cross-series configurations.

The Largest All-Electric Crane Hoists (120-160 t SWL)

Main hoist drives on the largest all-electric cranes being built today — offshore heavy-lift vessel cranes, shipyard gantry cranes, and heavy-construction tower cranes at 120-160 tonne SWL. The ZL200 at ratio 80-200 with 1,000-1,500 kW motors at 5,000 rpm provides the hoist torque with 368,000 Nm peak capacity — exceeding any transient load a crane at this class will encounter. The slewing drive y wheel drive complete the all-electric mega-class crane platform.

Electric Mining Main Production Winders (700-1,100 m)

Main production winders at moderate-to-deep mines where the sustained drum torque falls within 175,000 Nm. With 20-25 tonne skip loads and shaft depths of 700-1,100 metres, the combined skip, ore, and rope weight typically produces sustained drum torques of 120,000-170,000 Nm — within the ZL200 continuous. The 5,000 rpm input and 130 kW Pt provide the motor flexibility and thermal capacity for production winding at 300-500 cycles per day with 20-35% regen recovery.

Dual-ZL200 Configurations (350,000 Nm)

Two ZL200 units driving one drum through a torque-combining gearbox produce up to 350,000 Nm continuous — matching the 419W3 mega-class ceiling from an all-electric platform. This configuration serves the absolute largest electric winch applications: electric AHTS main winches, electric deep-ocean deployment systems for permanent subsea installations, and electric mining production winders at depths where a single ZL200 is insufficient.

Why does the ZL series stop at 175,000 Nm when the 4xxW reaches 330,000 Nm?

The 4xxW series operates at 1,000-2,500 rpm with straight-cut gears — allowing larger gear modules and lower tooth peripheral velocities at higher torques. The ZL series operates at 4,000-5,000 rpm with helical gears — the higher speed limits the maximum gear module before the tooth peripheral velocity exceeds the safe operating envelope. To reach 330,000 Nm at 5,000 rpm with helical gears would require a housing diameter impractically large for drum integration. The 4xxW trades speed for torque; the ZL trades torque for speed, precision, and efficiency. They are complementary, not competing.

How does the dual-ZL200 configuration compare to a single 419W3?

Dual ZL200 through a torque combiner produces 350,000 Nm continuous — matching the 419W3 at 330,000 Nm with 6% margin. The dual-ZL200 provides regen braking, helical-quiet operation, DIN 5-6 accuracy, and 5,000 rpm input from two independent electric motors with full redundancy (one unit can carry the load if the other fails). The 419W3 provides a single integrated unit with a 2,500 Nm internal brake, lower total weight (3,200 kg vs approximately 2x ZL200 housing weight + combiner), and FEM M6 sustained duty certification. For electric platforms: dual ZL200. For hydraulic platforms and sustained mega-class duty: 419W3.

What motor configuration is typical for the ZL200 at 150 t crane duty?

At ratio 100 with 700 mm PCD drum, 12-part reeving, SWL 150 t at 8 m/min: motor power approximately 1,200-1,500 kW. At 5,000 rpm: a single PMSM motor in an IEC 450 frame (approximately 1,500-2,000 kg). The single-motor electric architecture is simpler than the quad-hydraulic-motor configuration the 4xxW mega-class requires — one motor, one VFD, one coupling, one input shaft. For the largest cranes (150+ tonnes), this simplicity translates to fewer failure modes, lower maintenance cost, and faster commissioning.

What is the 130 kW Pt significance for motor selection?

At 1-stage: the ZL200 can transmit 130 kW continuously without external cooling — sufficient for high-speed light-load winch operations. At 2-stage (the mainstream crane configuration, ratios 15-50): Pt is approximately 95 kW without cooler. With a standard external cooler: approximately 145 kW. Most 120-160 t crane hoists with 1,000-1,500 kW motors at 30-50% duty produce average thermal loads of 60-100 kW — within the 2-stage Pt with a cooler. The 130 kW maximum ensures the ZL200 can serve even the most intensive crane duty cycles with a single external cooler, without the oversized cooling systems that smaller ZL models would require at the same power level.

What is the expected service life of the ZL200?

Life-rated at 100,000 hours (N2xh=100,000). At heavy crane duty (3,000-5,000 hours per year): 20-33 years of theoretical life. First overhaul at 25,000-30,000 hours. The ZL200 housing mass and gear module provide the largest thermal and fatigue margins in the ZL series, which historically extends actual service life 10-20% beyond the statistical target. Oil changes every 2,000 hours. Seal replacement at 10,000-15,000 hours. Bearing inspection at 20,000 hours. Gear set inspection at 25,000 hours.

What comes after the ZL200 in the Korea Ever-Power catalogue?

The ZR winch drive series — right-angle input configuration at 55,000-175,000 Nm continuous, 2-5 stages, 3,000-3,300 rpm input. The ZR series provides an alternative motor-gearbox geometry for applications where the motor must be mounted perpendicular to the drum axis rather than coaxial. Beyond the ZL and ZR standard catalogue, Korea Ever-Power offers custom engineering for torque requirements exceeding 350,000 Nm (dual ZL200) or for unique geometry and duty cycle constraints. Contact Corea Ever-Power for projects beyond the standard catalogue.

150 t all-electric offshore crane — the largest all-electric crane under contract. ZL200 at ratio 120, 2-stage, 1,400 kW PMSM at 4,800 rpm. The ZL200 replaced a 416W3 + dual hydraulic motor specification that was the baseline when the vessel was first designed. Weight saving: 1,100 kg at the crane head compared to the hydraulic baseline. The 368,000 Nm peak absorbed the classification proof-load test (187.5 t equivalent drum torque) with zero VFD faults. Commissioning time: 3 days (motor alignment + VFD parameterisation + brake test). The hydraulic crane commissioning on our previous vessel: 11 days. This crane has set the benchmark for every heavy-lift vessel crane our company will build for the next decade.

Main production winder at a 950-metre copper-gold mine, ZL200 at ratio 320, 3-stage, 1,100 kW AC motor at 4,200 rpm. The skip carries 24 tonnes; rope weight at full depth is 5,700 kg. Sustained drum torque during loaded hoist: 168,000 Nm — 96% of ZL200 continuous. This is the deepest shaft we could serve with the ZL200 at this skip size — 50 metres deeper and the torque would exceed the continuous rating. The 414W3 was the alternative at 140,000 Nm continuous — which would have been exceeded at this depth. The ZL200 provides the 35,000 Nm of additional continuous capacity that the 414W3 could not, plus regen recovery of USD 510,000 per year. The mine is currently the deepest production shaft operating on a ZL electric winch drive.

Dual-ZL200 configuration on an all-electric AHTS vessel — the first dual-ZL winch drive installation. Two ZL200 units at ratio 200, each driven by a 900 kW AC motor, torque-combined into a single drum at 350,000 Nm continuous capacity. The vessel completed its first ultra-deepwater anchor deployment at 2,000 metres — 260 tonnes of chain handled by the dual-ZL200 with full regen during recovery. Energy saving versus the hydraulic twin-motor 419W3 equivalent: 38% per deployment cycle. The 4-star reflects the integration complexity: the torque-combining gearbox between the two ZL200 units added 350 kg and 200 mm of axial length to the winch assembly — dimensions that were not in the initial vessel stern layout. For future dual-ZL200 projects, publishing a combined unit dimensional envelope (both ZL200s + combiner) as a single assembly drawing would prevent the stern structure redesign we had to perform mid-build.