{"id":972,"date":"2026-06-22T03:39:07","date_gmt":"2026-06-22T03:39:07","guid":{"rendered":"https:\/\/planetary-gearboxes.com\/?post_type=product&p=972"},"modified":"2026-06-22T03:39:07","modified_gmt":"2026-06-22T03:39:07","slug":"zl55-winch-drive-planetary-gearbox-1-5-stage","status":"publish","type":"product","link":"https:\/\/planetary-gearboxes.com\/th\/product\/zl55-winch-drive-planetary-gearbox-1-5-stage\/","title":{"rendered":"ZL55 Winch Drive Planetary Gearbox \u2014 1-5 Stage"},"content":{"rendered":"
\n

<\/p>\n

\n
\n
FIRST 5-STAGE ZL WINCH<\/span>
\nFILLS THE 4xxW GAP<\/span><\/div>\n

ZL55 \u2014 55,000 Nm<\/h2>\n

Five stages. The ceiling lifts.<\/p>\n

\n
\n
55,000<\/div>\n
Nm Cont.<\/div>\n<\/div>\n
\n
112,000<\/div>\n
Nm Peak<\/div>\n<\/div>\n
\n
1-5<\/div>\n
\u0e40\u0e27\u0e17\u0e35<\/div>\n<\/div>\n
\n
4.14-2,190<\/div>\n
\u0e2d\u0e31\u0e15\u0e23\u0e32\u0e2a\u0e48\u0e27\u0e19<\/div>\n<\/div>\n<\/div>\n<\/div>\n

The EP-ZL55 is the fourth model in the ZL electric winch drive planetary gearbox<\/a> series \u2014 and the first to offer five planetary stages. The ZL30, ZL35, and ZL45 all cap at four stages; the ZL55 adds a fifth, extending the maximum ratio from the ZL45 ceiling of 1,745 to 2,190 and reducing the minimum achievable drum speed by a further 26%. At 55,000 Nm continuous torque, the ZL55 also occupies the torque space between the 4xxW 413W3 (42,500 Nm) and the mega-class 414W3 (140,000 Nm) \u2014 a 97,500 Nm gap that the hydraulic-era catalogue never filled because few hydraulic winch applications exist in this range. The electric era, with its different motor-speed-torque curves and its different cost structure, creates demand at torque levels the hydraulic catalogue bypassed.<\/p>\n

\"ZL55<\/p>\n<\/section>\n

<\/p>\n

\n

ZL55 Electric Winch Drive Planetary Gearbox \u2014 Technical Parameters<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n
Continuous torque (N2xh=100,000)<\/td>\n55,000 Nm<\/td>\n<\/tr>\n
\u0e41\u0e23\u0e07\u0e1a\u0e34\u0e14\u0e2a\u0e39\u0e07\u0e2a\u0e38\u0e14<\/td>\n112,000 Nm (2.04x continuous)<\/td>\n<\/tr>\n
Gear ratio range<\/td>\n4.14 to 2,190 (1-5 stages)<\/td>\n<\/tr>\n
Maximum input speed<\/td>\n4,000 rpm<\/td>\n<\/tr>\n
Thermal power (Pt)<\/td>\n24 – 74 kW (varies by stage count)<\/td>\n<\/tr>\n
Gear type<\/td>\nHelical planetary, 3-planet, DIN 5-6<\/td>\n<\/tr>\n
Integrated brake<\/td>\nNone (motor brake or external brake)<\/td>\n<\/tr>\n
Sealing<\/td>\nMulti-lip FKM, IP67+<\/td>\n<\/tr>\n
Housing<\/td>\nDuctile iron QT600-3<\/td>\n<\/tr>\n
Gear material<\/td>\n20CrMnTi, HRC 58-62<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n

<\/p>\n

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Five Stages \u2014 What the Fifth Planetary Stage Provides and What It Costs<\/h2>\n

The ZL30, ZL35, and ZL45 stop at four stages. The ZL55 adds a fifth. This is not a trivial extension \u2014 it is a step-change in what the gearbox can deliver at the slow end of the speed range, balanced against a measurable cost in thermal capacity and axial length.<\/p>\n

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\n
\n
\n

What it provides<\/strong><\/p>\n

The fifth stage multiplies the 4-stage maximum ratio by approximately 3.5-5.6x (the per-stage ratio of the additional stage). For the ZL55: 4-stage maximum approximately 400 x 5.5 = 2,190. The drum speed at ratio 2,190 with a 3,000 rpm motor is 1.37 rpm \u2014 one revolution every 44 seconds on a 400 mm PCD drum, producing a line speed of 1.72 m\/min. This is deep-ocean instrument deployment territory, precision borehole cable control, and nuclear fuel handling speed.<\/p>\n<\/div>\n

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What it costs<\/strong><\/p>\n

Each additional stage adds approximately 60-100 mm of axial length to the gearbox housing, 3 planet gears, 1 sun gear, 6 bearings, 1 carrier, and one more heat-generating mesh. The 5-stage ZL55 Pt drops to approximately 24 kW \u2014 the lowest in the thermal range \u2014 because the fifth mesh generates heat that the housing surface area cannot fully dissipate without external cooling. For 5-stage applications, an external oil cooler is essentially mandatory for any continuous duty above 50% of the thermal limit.<\/p>\n<\/div>\n

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When it matters<\/strong><\/p>\n

The fifth stage matters only when the application needs ratios above the 4-stage ceiling (~400 for the ZL55) or when the additional reduction provides a control advantage \u2014 for example, allowing a standard 3,000 rpm motor to achieve sub-2 m\/min line speeds without requiring the VFD to operate the motor at impractically low frequencies where motor torque and cooling degrade. The 5th stage keeps the motor in its efficient operating band while delivering ultra-slow drum speeds through mechanical reduction.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

\"ZL55<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Peak-to-Continuous 2.04:1 \u2014 The ZL Trend Converges on the 4xxW Baseline<\/h2>\n

The ZL peak-to-continuous ratio has been decreasing with each larger model: ZL30 at 2.8:1, ZL35 at 2.5:1, ZL45 at 2.35:1, and now ZL55 at 2.04:1 \u2014 approaching the ~2.0:1 that defines the 4xxW series. This convergence is not a design failure. It is physics.<\/p>\n

\n\n\n\n\n\n\n\n\n\n
\u0e41\u0e1a\u0e1a\u0e2d\u0e22\u0e48\u0e32\u0e07<\/th>\n\u0e15\u0e48\u0e2d\u0e40\u0e19\u0e37\u0e48\u0e2d\u0e07<\/th>\nPeak<\/th>\n\u0e2d\u0e31\u0e15\u0e23\u0e32\u0e2a\u0e48\u0e27\u0e19<\/th>\nTrend<\/th>\n<\/tr>\n<\/thead>\n
ZL30<\/td>\n27,000<\/td>\n75,500<\/td>\n2.80x<\/td>\n\u2588\u2588\u2588\u2588\u2588\u2588\u2588<\/td>\n<\/tr>\n
ZL35<\/td>\n34,000<\/td>\n85,000<\/td>\n2.50x<\/td>\n\u2588\u2588\u2588\u2588\u2588\u2588<\/td>\n<\/tr>\n
ZL45<\/td>\n40,500<\/td>\n95,000<\/td>\n2.35x<\/td>\n\u2588\u2588\u2588\u2588\u2588<\/td>\n<\/tr>\n
ZL55<\/td>\n55,000<\/td>\n112,000<\/td>\n2.04x<\/td>\n\u2588\u2588\u2588\u2588<\/td>\n<\/tr>\n
4xxW baseline<\/td>\n\u2014<\/td>\n\u2014<\/td>\n~2.0x<\/td>\n\u2588\u2588\u2588\u2588<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
Why this happens: <\/span>
\nAs gear module size increases (to carry more torque), the tooth root stress at peak loading approaches the bending endurance limit more closely \u2014 leaving less margin between the continuous rating and the peak rating. The ZL30 small gears have proportionally more material headroom above their continuous rating. The ZL55 larger gears are operating closer to their material limit at continuous, so the peak-to-continuous gap narrows. At the ZL55 level, the 2.04:1 peak ratio still provides 57,000 Nm of headroom above continuous \u2014 more than enough for grab crane impacts and marine snatch loads \u2014 but the proportional advantage over the 4xxW series has converged.<\/span><\/div>\n<\/section>\n

<\/p>\n

\n

55,000 Nm \u2014 The Five-Stage Electric Winch Drive for Heavy Marine and Mining Applications<\/h2>\n

\"ZL55<\/p>\n

\n
\n

Heavy Electric Offshore Cranes (30-50 t SWL)<\/h3>\n

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 \u2014 delivering heavy-lift torque with electric-era benefits. The slewing drive<\/a> handles the crane rotation on the same all-electric vessel platform.<\/p>\n<\/div>\n

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Electric Mining Main Auxiliary Hoists<\/h3>\n

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 \u2014 transformers, ventilation fans, drill rigs \u2014 where the descent must be controlled to within centimetres per second.<\/p>\n<\/div>\n

\n

Heavy Industrial Electric Overhead Cranes<\/h3>\n

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<\/a> \u2014 ladle attachment, mould clamping, and furnace-door handling \u2014 that generate transient torques approaching 2x continuous. The helical gears produce noise levels acceptable inside enclosed industrial buildings.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

The ZL Electric Winch Drive Family<\/h2>\n
\n
\n

\"Winch<\/p>\n

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Full ZL Winch Drive Range \u2192<\/a><\/h3>\n

ZL75 (70,000 Nm) to ZL200 (175,000 Nm) for the heaviest electric winch systems.<\/p>\n<\/div>\n<\/div>\n

\n

\"4xxW<\/p>\n

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4xxW Hydraulic Winch Drives \u2192<\/a><\/h3>\n

413W3 (42,500 Nm) and 414W3 (140,000 Nm) for hydraulic platforms at adjacent torque levels.<\/p>\n<\/div>\n<\/div>\n

\n

\"ZL<\/p>\n

\n

ZL Wheel Drive Planetary Gearbox \u2192<\/a><\/h3>\n

Same ZL architecture for heavy electric vehicle propulsion and crane travel drives.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Electric Winch Drive Planetary Gearbox \u2014 ZL55 Five-Stage FAQ<\/h2>\n
\n
\n

Why does the 5-stage option appear at the ZL55 and not at the ZL30?<\/h3>\n

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.<\/p>\n<\/div>\n

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What is the thermal power limit at 5 stages and how does it affect motor selection?<\/h3>\n

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.<\/p>\n<\/div>\n

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How does the ZL55 fill the gap between the 4xxW 413W3 and 414W3?<\/h3>\n

The 4xxW catalogue jumps from 42,500 Nm (413W3) to 140,000 Nm (414W3) \u2014 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.<\/p>\n<\/div>\n

\n

Does the ZL55 share any components with the ZL45?<\/h3>\n

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.<\/p>\n<\/div>\n

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At 2.04:1 peak-to-continuous, does the ZL55 still offer a meaningful advantage over the 4xxW series for shock loads?<\/h3>\n

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.<\/p>\n<\/div>\n

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What axial length does the 5-stage ZL55 add compared to the 3-stage?<\/h3>\n

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 \u2014 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 \u0e40\u0e01\u0e32\u0e2b\u0e25\u0e35 \u0e40\u0e2d\u0e40\u0e27\u0e2d\u0e23\u0e4c\u0e1e\u0e32\u0e27\u0e40\u0e27\u0e2d\u0e23\u0e4c<\/a> for exact dimensional data at your specific ratio and stage count.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Field Reports<\/h2>\n
\n
\n
\n
\u0e40\u0e2d\u0e47\u0e19<\/div>\n
\n
Nikolaj R. \u2014 Electric Offshore Crane OEM Engineer<\/div>\n
Verified Purchase \u00b7 Ulsteinvik, Norway \u00b7 April 2026<\/div>\n<\/div>\n
\u2605\u2605\u2605\u2605\u2605<\/div>\n<\/div>\n

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 \u2014 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.<\/p>\n<\/div>\n

\n
\n
\u0e1e\u0e35<\/div>\n
\n
Paul D. \u2014 Mine Electrical Systems Superintendent<\/div>\n
Verified Purchase<\/div>\n<\/div>\n
\u2605\u2605\u2605\u2605\u2605<\/div>\n<\/div>\n

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 \u2014 drill rigs, ventilation fans, pumps \u2014 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 \u2014 measured at 31 kWh per descent cycle for a 12-tonne load from surface to the 620-metre level.<\/p>\n<\/div>\n

\n
\n
\u0e27<\/div>\n
\n
Dr. Wei L. \u2014 Deep-Ocean Instrument Systems Engineer<\/div>\n
Verified Purchase \u00b7 May 2026<\/div>\n<\/div>\n
\u2605\u2605\u2605\u2605\u2606<\/div>\n<\/div>\n

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 \u2014 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 \u2014 well within its efficient torque band \u2014 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 \u2014 it should be prominently stated on the 5-stage data sheet.<\/p>\n<\/div>\n<\/div>\n<\/section>\n<\/div>","protected":false},"excerpt":{"rendered":"

The EP-ZL55 is the first winch drive planetary gearbox in the ZL electric series to break through the four-stage ceiling \u2014 adding a fifth planetary stage that extends the maximum ratio from the ZL45 limit of 1,745 to 2,190 and opens an entirely new operating domain for electric winch systems. At 55,000 Nm continuous and 112,000 Nm peak, the ZL55 also crosses the torque threshold where the ZL electric architecture begins to overlap with the 4xxW mega-class territory. There is no 4xxW model between the 413W3 (42,500 Nm) and the 414W3 (140,000 Nm) \u2014 a gap of nearly 100,000 Nm. The ZL55 at 55,000 Nm fills the lower end of that gap with an electric-native product that the 4xxW hydraulic series never needed to provide.<\/div>","protected":false},"featured_media":974,"comment_status":"open","ping_status":"closed","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[969],"product_tag":[],"class_list":["post-972","product","type-product","status-publish","has-post-thumbnail","product_cat-winch-drive-planetary-gearbox","first","instock","shipping-taxable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/product\/972","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/comments?post=972"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/media\/974"}],"wp:attachment":[{"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/media?parent=972"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/product_brand?post=972"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/product_cat?post=972"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/th\/wp-json\/wp\/v2\/product_tag?post=972"}],"curies":[{"name":"\u0e14\u0e31\u0e1a\u0e40\u0e1a\u0e34\u0e25\u0e22\u0e39\u0e1e\u0e35","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}