ZR120 Winch Drive Planetary Gearbox — Right-Angle

The additional planetary stage provides more reduction before the torque reaches the bevel. At a given output torque (133,000 Nm), the bevel input torque at 3-stage is lower than at 2-stage because the first two planetary stages have already multiplied the motor torque. Lower bevel input torque = lower bevel tooth stress = longer bevel gear life. The bevel tooth stress at 3-stage drops from 98% (the unacceptable 2-stage level) to approximately 75% of the endurance limit — restoring the design margin to comfortable levels.

The 3-stage minimum means the ZR120 minimum achievable ratio is higher than the ZR95 2-stage minimum. Where the ZR95 at 2-stage could reach ratios as low as 15, the ZR120 at 3-stage starts at approximately 50. For applications needing low ratios (fast drum speeds, direct-drive-like operation), the ZR95 at 115,000 Nm with 2-stage offers lower ratios than the ZR120 at 133,000 Nm with 3-stage. The ratio range is a design trade-off with the stage count.

Three stages distribute the total ratio across more gear meshes — each individual mesh carries a lower per-stage load. This reduces the contact stress on every gear in the train, not just the bevel. The result is more uniform wear across the gear train and a more predictable maintenance profile — the gears and bearings wear at similar rates rather than the bevel wearing faster than the planetary. For maintenance planning, this means the entire gear train can be inspected and overhauled on the same schedule. Contact Korea Ever-Power for overhaul scheduling at your specific duty profile.

At 3,000 rpm, the ZR120 accepts any standard 2-pole motor at 50 Hz without speed derating or VFD frequency limiting. The motor runs at its rated speed, at rated voltage, at rated efficiency. No power derating, no thermal derating, no bearing speed limit concern. For installations where the electrical supply is 50 Hz (Europe, Asia, Africa, South America, Australia, the Middle East — approximately 70% of the global electrical grid), the ZR120 at 3,000 rpm is the zero-compromise motor match.

For 60 Hz electrical systems (North America, parts of South America, Japan, South Korea): a 2-pole motor at 60 Hz runs at 3,600 rpm synchronous — exceeding the 3,000 rpm limit. Solution: the VFD limits the motor frequency to 50 Hz (3,000 rpm), or a 4-pole motor at 60 Hz (1,800 rpm) is selected. Both are standard configurations. For marine vessels with 60 Hz generators, the VFD frequency limit is a single parameter change. The ZR120 is compatible with every global electrical standard through standard motor and VFD practice.

Heavy Electric Cranes in Constrained Geometry (80-120 t)

Electric cranes at 80-120 tonne SWL where the machinery room constrains the coaxial geometry. The ZR120 delivers 95% of the 414W3 mega-class continuous from a right-angle motor mount. The slewing drive Und wheel drive complete the all-electric crane system. The 280,000 Nm peak exceeds the 417W3 mega-class continuous — absorbing transient overloads from grab operations, subsea deployment, and emergency stops.

Heavy Marine Anchor Handling and Mooring Winches

Main anchor handling and permanent mooring winches on AHTS vessels, FPSOs, and semi-submersible platforms where the drum axis runs athwartship. The ZR120 at 133,000 Nm provides the anchor chain tension and mooring line holding capacity that the 414W3 mega-class traditionally served — from an electric platform with regen, DIN 5-6 precision, and IP67+ sealing for the deck-mounted marine environment.

Electric Mining Main Production Winders (500-800 m)

Main production winders on mine headframes where the motor mounts perpendicular to the drum. The ZR120 at 133,000 Nm with 600-900 kW motors at 3,000 rpm provides the winding torque for 500-800 metre shafts with 15-22 tonne skip loads. Regen recovery 20-35%. The 3,000 rpm speed matches the standard mine electrical infrastructure — 2-pole motors, 50 Hz supply, standard VFD — without special motor procurement.

How much longer is the ZR120 at 3-stage versus the ZR95 at 2-stage?

Approximately 80-120 mm, depending on the specific ratio combination. The ZR95 at 2-stage is approximately 350-400 mm behind the drum mounting face. The ZR120 at 3-stage is approximately 450-520 mm. For installations with 400-450 mm of available depth, the ZR95 at 2-stage (115,000 Nm) is the last option. For installations with 500+ mm, the ZR120 at 3-stage (133,000 Nm) fits comfortably. The 80 mm difference is the cost of the 16% torque increase from ZR95 to ZR120.

Does the ZR120 share planetary spare parts with the ZL120?

Yes. The planetary stages (stages 2-5 in ZR120, stages 1-5 in ZL120) share gear sets, bearings, carriers, and seals at overlapping ratios. Only the bevel stage and input housing are ZR-specific. Fleet operators running both ZR120 and ZL120 benefit from shared planetary spare parts — reducing total inventory cost by approximately 40-60% compared to maintaining separate kits.

Can the ZR120 replace the 414W3 mega-class for marine winch applications?

For cyclic duty where sustained torque stays below 133,000 Nm: yes. The ZR120 provides 95% of the 414W3 continuous with 280,000 Nm peak (exceeding the 417W3 continuous), regen braking, DIN 5-6 precision, and the right-angle geometry that athwartship marine winches require. For sustained multi-hour holding above 133,000 Nm (AHTS weather standby, permanent mooring tensioning), the 414W3 at 140,000 Nm continuous remains the correct specification.

What motor frame is typical for the ZR120 at 100 t crane duty?

At ratio 100, 600 mm PCD drum, 10-part reeving, 100 t at 10 m/min: motor power approximately 700-900 kW. At 3,000 rpm: IEC 355-400 frame (900-1,400 kg). The perpendicular motor mount places this weight beside or below the drum rather than behind it — improving the structural load distribution on the drum support. For marine winches where the motor mounts on a steel foundation bolted to the deck, the motor weight is transferred directly to the vessel structure rather than cantilevered from the drum.

What overhaul interval applies to the ZR120?

The 100,000-hour life rating applies. The 3-stage configuration distributes wear more evenly across the gear train than the 2-stage models — the bevel gears no longer wear faster than the planetary gears. Target first overhaul at 25,000-30,000 hours for industrial and mining applications, 20,000-25,000 hours for marine. Oil changes every 1,500-2,000 hours depending on environment. Oil sampling every 500-1,000 hours. Bevel and planetary gears inspected together at each overhaul. Contact Korea Ever-Power for the environment-specific maintenance schedule.

100 t offshore platform crane, hydraulic-to-electric conversion. The machinery room offered 480 mm behind the drum — enough for the ZR120 at 3-stage (465 mm installed depth) but not enough for the ZR95 at the required 4-stage ratio (510 mm). The ZR120 at ratio 100, 3-stage, 800 kW motor delivered 133,000 Nm — 95% of the 414W3 that the crane originally used. The 5% torque reduction was approved by the classification society because the crane's maximum operating torque (measured from 3 years of load recorder data) was 118,000 Nm — well within the ZR120 capacity. The conversion eliminated the HPU and 180 metres of hydraulic hose. Regen recovery: 21% over 10 months. The crane is now the largest right-angle electric crane conversion in the North Sea fleet.

Permanent mooring winch on an FPSO, ZR120 at ratio 80, 3-stage, 600 kW AC motor at 3,000 rpm. The winch maintains constant tension on 8 mooring lines at 40-70% of continuous rating (53,000-93,000 Nm) for months at a time. The ZR120 3-stage thermal distribution at this sustained duty keeps the oil temperature stable at 62-68 deg C in the tropical environment (32 deg C ambient) — well within limits. The 280,000 Nm peak absorbed a sudden squall event that produced 2.6x line tension on the windward mooring point — the highest transient the vessel has experienced since commissioning. The winch system automatically adjusted the line length through the VFD speed control to restore the target tension within 8 seconds.

Main production winder at a 720-metre gold mine, ZR120 at ratio 280, 4-stage, 750 kW AC motor at 3,000 rpm mounted vertically. Skip weight 20 tonnes; rope weight at full depth 3,800 kg. Sustained drum torque during loaded hoist: 124,000 Nm — 93% of ZR120 continuous. Regen recovery: 26% of hoist energy (USD 380,000 annual saving at current electricity rates). The 4-star reflects a motor alignment observation: at 3,000 rpm through the right-angle bevel, the alignment tolerance between the motor shaft and the bevel input shaft is tighter than at the 3,100 rpm models — the laser alignment required two iterations during commissioning instead of the typical one. For ZR120 installations at 3,000 rpm, specifying laser alignment with a 0.02 mm tolerance (instead of the 0.05 mm standard for the 3,100 rpm models) would reduce the commissioning alignment time.