ZL85 Winch Drive Planetary Gearbox

Nuclear fuel assemblies are lowered into reactor pools at speeds below 5 mm/sec to prevent fuel rod damage and to allow real-time gamma monitoring during the descent. At ratio 3,509 with a 1,000 rpm motor on a 250 mm PCD drum: line speed = 0.22 m/min = 3.7 mm/sec. The motor encoder at 10,000 PPR through ratio 3,509 produces 35,090,000 pulses per drum revolution — each pulse corresponding to 22 microns of cable travel. This resolution exceeds the positional accuracy required by nuclear fuel handling procedures.

Full-ocean-depth research instruments (hadal zone landers, abyssal sediment corers) deployed to 6,000-11,000 metres at controlled descent speeds below 1 m/min through the entire water column. At ratio 3,509 with a 2,000 rpm motor on a 300 mm PCD drum: 0.54 m/min. The 88,000 Nm continuous torque handles the combined instrument weight (500-2,000 kg) plus the cable weight at full depth (5,000-15,000 kg for deep-ocean wire). The IP67+ sealing withstands the marine deck environment on research vessels.

Cable-stayed bridge strand tensioning, high-voltage overhead line sagging, and industrial cable pre-tensioning systems where the cable must be pulled to a precise tension (measured in kN) and held. The ZL85 at ratio 2,000-3,509 provides the mechanical advantage to apply tension with millimetre-level control using a standard electric motor — the high ratio converts small motor torque adjustments into correspondingly small cable force changes, enabling the operator to dial in the exact tension without overshooting. Contact Корея Вечная Сила for tensioning system integration details.

Heavy Electric Cranes (50-80 t SWL)

All-electric cranes at the upper boundary of the mobile and offshore market. The ZL85 at ratio 80-180, 2-3 stage, paired with 400-800 kW electric motors covers the 50-80 tonne SWL range with one product. The 200,000 Nm peak absorbs the dynamic overloads from heavy grab operations, container handling, and subsea deployment that define this crane class. The slewing drive и wheel drive complete the platform from the same ZL architecture.

Deep-Ocean and Full-Depth Winch Systems

Research vessel and military deep-ocean winches deploying instruments, sensors, and recovery systems to 6,000-11,000 metres. The ZL85 at ratio 2,000-3,509 (5-stage) provides the ultra-slow descent speed (0.3-0.8 m/min) that deep-ocean protocols require, while the 88,000 Nm continuous handles the instrument weight plus the full cable weight at maximum depth — which can exceed 15,000 kg for full-ocean-depth wire. The DIN 5-6 accuracy plus motor encoder enables depth-position control within centimetres at any point in the water column.

Nuclear and High-Consequence Handling

Fuel handling machines, spent fuel cask cranes, and decommissioning equipment in nuclear power stations where the load must move at precisely controlled sub-centimetre-per-second speeds and the winch must operate in radiation environments that degrade hydraulic seals faster than gear steel. The ZL85 all-metal gear train is inherently more radiation-tolerant than the elastomeric seals in hydraulic systems — the FKM seals in the ZL85 are the most radiation-sensitive components and can be replaced at scheduled intervals.

How does the ZL85 achieve ratio 3,509 when the larger ZL75 caps at 1,502?

The ZL85 housing diameter is larger than the ZL75, and the 5-stage gear set uses a tooth count combination that produces a higher per-stage ratio at each of the five stages. The ZL75 five-stage gears are optimised for the 2.5:1 peak-to-continuous balance; the ZL85 five-stage gears are optimised for maximum ratio reach. This means the ZL85 five-stage maximum ratio (3,509) is substantially higher than the ZL75 five-stage (1,502), even though both use five stages. The internal gear geometry — tooth counts, module, and planet carrier design — is different between the two models, and the ZL85 combination happens to produce the highest achievable ratio in the entire product family.

At ratio 3,509, can the motor encoder still resolve individual cable position increments?

Yes. A standard 10,000 PPR motor encoder through ratio 3,509 produces 35,090,000 encoder counts per output revolution. On a 300 mm PCD drum (942 mm circumference), each count corresponds to 0.027 mm (27 microns) of cable travel. A 17-bit absolute encoder (131,072 positions per revolution) produces 460 billion effective positions per output revolution — 2 microns per count. The practical resolution limit is the cable stretch under load (0.1-0.5% of deployed length) and the mechanical backlash of the gear train (less than 3 arc-minutes at DIN 5-6), not the encoder resolution.

What thermal power does the ZL85 provide at 5-stage for deep-ocean winch duty?

At 5 stages: Pt is approximately 26 kW without external cooling. Deep-ocean winch duty at sub-1 m/min is inherently low-power: a 2-tonne instrument descending at 0.5 m/min requires approximately 0.16 kW of mechanical power at the drum. Even including the cable weight (which increases with depth), the power demand at 5-stage ultra-slow speeds rarely exceeds 10-15 kW sustained — well within the 26 kW thermal limit. External cooling is needed only if the winch also performs fast retrieval (motor at high speed) as part of the same duty cycle.

Is the ZL85 suitable for nuclear fuel handling crane applications?

The ZL85 gear train (all-metal, no elastomeric components in the torque path) is inherently more radiation-tolerant than hydraulic winch drives. The FKM seals are the most radiation-sensitive components — they degrade at cumulative doses above approximately 10^4 - 10^5 Gray (depending on the elastomer grade). For fuel handling machines operating in moderate radiation fields (10-100 mSv/hr), the seals should be inspected annually and replaced on a 3-5 year cycle based on hardness testing. The gear steel, bearing steel, and housing iron are unaffected by radiation at levels encountered in fuel handling operations. Consult with Korea Ever-Power for radiation-compatible seal material options.

How does the ZL85 compare to the ZL75 for mainstream crane duty?

The ZL85 provides 26% more continuous torque (88,000 vs 70,000 Nm) and 14% more peak (200,000 vs 175,000 Nm). For cranes in the 50-60 t range, the ZL75 is adequate. For 60-80 t cranes or for applications where the duty cycle regularly approaches the continuous limit, the ZL85 provides meaningful margin. The ZL85 also reaches ratio 3,509 at five stages versus 1,502 for the ZL75 — relevant only for the ultra-slow precision applications. For mainstream crane hoisting (ratios 60-200), the two models are functionally equivalent except for the torque headroom.

What is the expected overhaul interval for the ZL85 at heavy crane duty?

At 70-80% of continuous rating (mainstream crane duty): target 25,000-30,000 hours between overhauls. The helical gear tooth contact pattern distributes wear more evenly than straight-cut gears, which typically extends bearing and gear life by 10-20% compared to an equivalent 4xxW model at the same torque utilisation. Oil changes every 2,000 hours (or 1,500 for marine environments). Seal replacement at 10,000-15,000 hours. Oil sampling every 500-1,000 hours depending on the operating environment. Contact Корея Вечная Сила for a maintenance schedule matched to your specific duty profile.

70 t all-electric offshore construction vessel crane, ZL85 at ratio 120, 2-stage, 700 kW PMSM. The crane completed a 65-tonne subsea template installation at 300 metres water depth — the heaviest electric crane lift to date on this vessel class. The 200,000 Nm peak absorbed the dynamic amplification (DAF 1.6) during the splash zone transit without a single VFD fault. Total crane energy consumption for the 4-hour installation sequence: 280 kWh, of which 68 kWh was recovered through regen during lowering. The hydraulic crane this system replaced consumed approximately 520 kWh equivalent in diesel fuel for the same operation. Energy saving: 46%.

Full-ocean-depth hadal zone lander deployment winch on a research vessel. ZL85 at ratio 3,200, 5-stage, 25 kW servo motor. The winch deployed a 1,200 kg instrument package to 8,200 metres in the Kermadec Trench at a controlled descent speed of 0.6 m/min. Total descent time: approximately 228 hours (9.5 days) of continuous operation. The motor maintained 1,920 rpm throughout — well within its thermal and torque operating band — while the drum turned at 0.6 rpm. Depth accuracy at touchdown: 1.2 metres at 8,200 m, measured by acoustic transponder. This is the deepest deployment our programme has achieved with a standard-catalogue winch drive. The ZL85 ratio 3,509 capability means we have headroom for the 10,000+ metre campaigns planned for next year.

Fuel handling machine main hoist at a pressurised water reactor. ZL85 at ratio 2,800, 5-stage, 15 kW servo motor. The winch lowers fresh fuel assemblies into the reactor pool at 3.5 mm/sec — within the nuclear safety authority requirement of less than 5 mm/sec. Positional accuracy measured by underwater camera: within 2 mm of the target grid position. The all-electric drive eliminated the hydraulic oil contamination risk in the fuel pool area — a major operational advantage over the previous hydraulic fuel handling machine. The 4-star is a qualification process observation: the nuclear safety authority required 18 months of qualification testing and documentation review before accepting the ZL85 for safety-related fuel handling duty. This timeline is inherent to nuclear regulation, not a product deficiency — but OEMs planning nuclear fuel handling projects should include this qualification lead time in the project schedule from the outset.