{"id":931,"date":"2026-06-18T05:32:56","date_gmt":"2026-06-18T05:32:56","guid":{"rendered":"https:\/\/planetary-gearboxes.com\/?post_type=product&p=931"},"modified":"2026-06-18T05:32:56","modified_gmt":"2026-06-18T05:32:56","slug":"402w2-winch-drive-planetary-gearbox","status":"publish","type":"product","link":"https:\/\/planetary-gearboxes.com\/ja\/product\/402w2-winch-drive-planetary-gearbox\/","title":{"rendered":"402W2 Winch Drive Planetary Gearbox Reducer"},"content":{"rendered":"
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NO INTEGRATED BRAKE<\/span>
\nTWO-STAGE<\/span><\/div>\n

402W2 \u2014 3,500 RPM, Multi-Ratio, Brake-Free<\/h2>\n

The EP-402W2 marks two transitions in the winch drive planetary gearbox<\/a> range: from single-stage to two-stage (unlocking ratios from 12.4 to 37.1), and from low-speed orbit motors to high-speed axial piston motors at 3,500 rpm. Both changes serve the same goal \u2014 delivering 4,000 Nm of drum torque with smaller, lighter, less expensive hydraulic motors that operate at higher speeds and lower pressures than the large-displacement units the single-stage 400\/401 models require.<\/p>\n<\/div>\n

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\u30c8\u30eb\u30af<\/span>4,000 Nm<\/span><\/div>\n
\u6bd4\u7387<\/span>12.4 \u2014 37.1<\/span><\/div>\n
Input<\/span>3,500 rpm<\/span><\/div>\n
\u91cd\u3055<\/span>115 kg<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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The absence of an integrated brake is not a cost reduction \u2014 it is an engineering statement. The 402W2 is designed for hoisting systems where the braking architecture is more sophisticated than a single spring-applied disc inside the gearbox. Marine deck cranes with DNV-certified counterbalance valves. Free-fall lifeboat davits with dual-independent hydraulic braking circuits. Heavy construction hoists with motor-mounted electromagnetic brakes plus separate drum-mounted calliper brakes. In each of these systems, an additional brake inside the gearbox would be redundant weight that contributes nothing to safety because the external braking system already provides the required holding capacity and regulatory compliance.<\/p>\n<\/div>\n

\"402W2<\/div>\n<\/div>\n<\/section>\n

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402W2 Winch Drive Planetary Gearbox \u2014 Technical Parameters<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n
\u5b9a\u683c\u51fa\u529b\u30c8\u30eb\u30af<\/td>\n4,000 Nm<\/td>\n<\/tr>\n
Gear ratio range<\/td>\n12.4 to 37.1 (two-stage planetary)<\/td>\n<\/tr>\n
Maximum input speed<\/td>\n3,500 rpm<\/td>\n<\/tr>\n
Maximum output speed<\/td>\n25 rpm (FEM M5 continuous duty)<\/td>\n<\/tr>\n
Mechanical efficiency<\/td>\n\u2265 95%<\/td>\n<\/tr>\n
Integrated brake<\/td>\nNone (external braking system required)<\/td>\n<\/tr>\n
Mounting<\/td>\nRotating housing flanges (direct drum integration)<\/td>\n<\/tr>\n
Dry weight<\/td>\nApprox. 115 kg<\/td>\n<\/tr>\n
\u6f64\u6ed1<\/td>\nOil bath splash, high-grade EP gear oil<\/td>\n<\/tr>\n
\u52d5\u4f5c\u6e29\u5ea6<\/td>\n-20 to +85 deg C (Viton seals available)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n

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No Gearbox Brake on a Winch \u2014 How to Hold a Suspended Load Safely<\/h2>\n

A brake-free winch drive planetary gearbox places the entire load-holding responsibility on the external system. Unlike a wheel drive without a brake (where the worst case is that the vehicle rolls), a winch drive without a brake means a suspended load WILL descend uncontrolled if the external braking fails. The system design must provide at least two independent means of holding the load.<\/p>\n

\"402W2<\/p>\n

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\u2460 Motor-Integrated Brake<\/h3>\n

Most axial piston motors (Rexroth A2FM\/A6VM, Eaton, Parker) offer a factory-integrated spring-applied, hydraulic-release brake on the motor shaft. This brake acts through the 402W2 gear ratio: a 30 Nm motor brake at ratio 25 produces 750 Nm of holding torque at the drum. Verify that this multiplied value exceeds the maximum suspended load torque at the outer cable layer. This is the simplest and most common external braking method for hydraulic winch systems.<\/p>\n<\/div>\n

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\u2461 Counterbalance Valves<\/h3>\n

A counterbalance valve in each motor port line prevents the load from overrunning the motor during lowering. When the pump stops, the counterbalance valve traps the oil in the motor circuit, locking the motor and drum in position. This provides a hydraulic hold that is independent of any mechanical brake. For crane applications certified to EN 13001 or FEM standards, the counterbalance valve is typically the primary hold mechanism, with the motor brake as the secondary.<\/p>\n<\/div>\n

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\u2462 External Drum Calliper Brake<\/h3>\n

A separate calliper brake mounted on the drum flange or the winch frame, acting directly on a brake disc welded to the drum cheek plate. This provides a completely independent mechanical hold that does not depend on the gearbox, the motor, or the hydraulic circuit. For safety-critical lifting (personnel hoisting, offshore crane certification), this third independent brake is often required by the classification society or the site safety standard as a tertiary hold mechanism.<\/p>\n<\/div>\n<\/div>\n

Critical safety requirement: <\/span>
\nNever operate the 402W2 with a suspended load unless at least two independent holding mechanisms are verified and functional. A single brake failure must not result in uncontrolled load descent. This is not a recommendation \u2014 it is a regulatory requirement under virtually every international lifting equipment standard.<\/span><\/div>\n<\/section>\n

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From 1,000 to 3,500 RPM \u2014 What the Two-Stage Architecture Unlocks<\/h2>\n

The single-stage 400W1 and 401W1 accept 1,000 rpm \u2014 the speed range of large-displacement, low-speed orbit motors (200-500 cc\/rev). The 402W2 at 3,500 rpm opens the door to small-displacement, high-speed axial piston motors (20-80 cc\/rev) that produce the same output torque at a fraction of the physical size and cost.<\/p>\n

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Smaller, Lighter Motors<\/strong><\/p>\n

A 250 cc\/rev orbit motor at 1,000 rpm weighs approximately 25-35 kg. A 45 cc\/rev axial piston motor producing the same torque at 3,500 rpm weighs 8-12 kg. On a marine crane where weight aloft directly affects vessel stability, this 60-70% motor weight reduction matters. On a construction hoist where the motor mounts inside a confined drum housing, the smaller physical envelope may be the only option that fits.<\/p>\n<\/div>\n

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Lower System Pressure<\/strong><\/p>\n

At higher motor speed and lower displacement, the system pressure required to produce the same output power is lower. Lower pressure means less stress on hoses, fittings, seals, and the pump \u2014 extending the service life of every component in the hydraulic circuit. The 402W2 ratio range (12.4-37.1) is specifically designed to allow the motor to operate at 2,000-3,000 rpm in the most efficient pressure band of a typical 250-350 bar axial piston circuit.<\/p>\n<\/div>\n

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Variable Speed Without Valving Complexity<\/strong><\/p>\n

Variable-displacement axial piston motors allow infinite speed variation by swashplate adjustment \u2014 from full speed to zero \u2014 without any external valving or flow control. Combined with the 402W2 ratio, this provides precise hoisting speed control from full-speed lifting down to controlled, creep-speed positioning, all from the motor control alone. The 402W2 gears transmit whatever speed and torque the motor delivers, in either direction, without mechanical restriction.<\/p>\n<\/div>\n

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Multi-Ratio Flexibility<\/strong><\/p>\n

The 12.4-37.1 ratio range allows the winch designer to match the gearbox to the exact motor displacement and pump flow available in the system. A crane OEM using a 40 cc\/rev motor at 120 L\/min pump flow selects ratio 25. A marine winch builder using a 63 cc\/rev motor at 80 L\/min selects ratio 15. The same 402W2 serves both, with the ratio chosen at order to match the specific hydraulic circuit design. Contact \u97d3\u56fd\u30a8\u30d0\u30fc\u30d1\u30ef\u30fc<\/a> with your motor and flow specifications for a verified ratio recommendation.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

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High-Speed Winch Drive Applications at 4,000 Nm<\/h2>\n

\"Two-stage<\/p>\n

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Marine Deck Cranes (5-10 Tonne SWL)<\/h3>\n

Deck-mounted knuckle-boom and telescopic cranes on supply vessels, research ships, and coastal freighters. These cranes use DNV- or Lloyd-certified hydraulic circuits with counterbalance valves as the primary hold mechanism and motor-integrated brakes as the secondary. The 402W2 brake-free design integrates directly into this architecture without adding a redundant third brake inside the gearbox. The slewing drive planetary gearbox<\/a> handles the crane rotation on the same vessel.<\/p>\n<\/div>\n

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Free-Fall Lifeboat Davit Recovery Winches<\/h3>\n

Free-fall lifeboat davits on offshore platforms and FPSOs use the winch only for recovery (hauling the lifeboat back to the stowed position after a drill or deployment). The launch is gravity-driven \u2014 no winch involvement. The 402W2 provides the 4,000 Nm needed to pull a 5-8 tonne lifeboat up a slipway at controlled speed, while the dual counterbalance valves in the davit hydraulic circuit provide all load-holding functions. Adding a brake inside the gearbox would not improve the safety case \u2014 it would only add weight to a system where davit head weight affects the platform structural loading calculation.<\/p>\n<\/div>\n

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Heavy Construction Material Hoists<\/h3>\n

High-capacity material hoists on large construction sites lifting 1-3 tonne loads of reinforcement bar, formwork panels, and precast elements. These hoists typically use motor-mounted electromagnetic brakes (primary) plus a drum-mounted calliper brake (secondary) as the dual-brake system required by construction lifting regulations<\/a>. The 402W2 delivers the drum torque while the external brakes handle the holding function, allowing the winch designer to specify each brake independently for optimal sizing and redundancy.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

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Need a Brake Inside? The 403W2 Alternative<\/h2>\n

If your application requires an integrated gearbox brake \u2014 because the external system cannot provide the required holding capacity or the applicable standard mandates a brake within the drum assembly \u2014 the 403W2 is the direct counterpart to the 402W2. Same 4,000 Nm torque, same two-stage architecture, same FEM M5 rating, plus an integrated 270 Nm multi-disc brake.<\/p>\n

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\"Slewing<\/p>\n

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Slewing Drive Planetary Gearbox \u2192<\/a><\/h3>\n

ZR series for crane boom rotation, davit luffing, and deck crane slewing on the same marine platforms.<\/p>\n<\/div>\n<\/div>\n

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\"Wheel<\/p>\n

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

EP wheel drives for mobile crane travel and construction site vehicle propulsion.<\/p>\n<\/div>\n<\/div>\n

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\"Precision<\/p>\n

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Precision Planetary Gearbox \u2192<\/a><\/h3>\n

EP-ZDS for crane level-wind mechanisms, winch rope guide systems, and davit position controls.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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Winch Drive Planetary Gearbox \u2014 Brake-Free and High-Speed FAQ<\/h2>\n
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Is it safe to operate a winch drive without an internal brake?<\/h3>\n

Yes, provided the external braking system meets the redundancy and holding capacity requirements of the applicable lifting standard. The 402W2 is not intended for systems that rely on a single internal gearbox brake as the sole load-holding mechanism. It is designed for systems where the braking is distributed across multiple independent components \u2014 motor brakes, counterbalance valves, and\/or external drum brakes \u2014 each sized to hold the full suspended load independently.<\/p>\n<\/div>\n

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What is the difference between the 402W2 and the 403W2?<\/h3>\n

Same torque (4,000 Nm), same two-stage architecture, same FEM M5 duty classification, same 3,500 rpm input speed. The 403W2 adds a 270 Nm multi-disc negative parking brake inside the housing, adding approximately 5 kg to the dry weight (120 vs 115 kg) and the ratio range shifts slightly (15.4-40 vs 12.4-37.1) due to the internal space consumed by the brake assembly. If the application needs an internal brake, specify the 403W2. If the external braking system provides all required holding capacity, the 402W2 is lighter and offers slightly lower ratios.<\/p>\n<\/div>\n

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Why does the 402W2 accept 3,500 rpm when the 400\/401 only accept 1,000 rpm?<\/h3>\n

The single-stage 400\/401 models use a single large sun gear that produces high tooth peripheral velocity at high input speeds. The two-stage 402W2 distributes the total reduction across two smaller gear sets, each operating at lower peripheral velocity than a single stage would at the same input speed. This allows the 402W2 to accept 3,500 rpm safely \u2014 the tooth velocity at each stage is comparable to the 400\/401 at 1,000 rpm. The two-stage design simultaneously unlocks higher input speeds and higher total ratio.<\/p>\n<\/div>\n

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Can the 402W2 be used for crane hoist certification under EN 13001?<\/h3>\n

Yes. EN 13001 requires the hoist mechanism to have at least two independent means of preventing uncontrolled load descent. The 402W2 provides the torque transmission function; the braking function must be provided by at least two external components (for example, motor brake + counterbalance valve, or motor brake + drum calliper brake). The gearbox itself is a torque transmission component, not a safety-holding component, in this system architecture. Provide the complete braking system design to the notified body for EN 13001 certification.<\/p>\n<\/div>\n

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What counterbalance valve pilot ratio is recommended for the 402W2 in a lowering application?<\/h3>\n

The counterbalance valve pilot ratio depends on the system operating pressure and the load-induced pressure at the motor ports. As a starting point: select a pilot ratio of 3:1 to 4.5:1. A higher pilot ratio provides smoother lowering control but requires more pilot pressure to open the valve. A lower pilot ratio is easier to open but may produce jerky lowering at low speeds. The optimal setting is determined by testing on the actual crane \u2014 adjust in 0.5:1 increments until the lowering speed is smooth and controllable at all load levels from zero to maximum.<\/p>\n<\/div>\n

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How does the winch drive planetary gearbox efficiency compare to a worm gear winch drive<\/a> at the same torque?<\/h3>\n

The 402W2 at 95% efficiency wastes 5% of input power as heat. A worm gear reducer at the same ratio range (12-37:1) operates at 55-75% efficiency, wasting 25-45% of input power as heat. For a 4,000 Nm winch lifting a 2-tonne load at 20 m\/min, the 402W2 requires approximately 14.0 kW of hydraulic input power. The worm gear would require 18.7-25.5 kW for the same lift \u2014 33-82% more power, all of which converts to heat inside a sealed drum housing. At this power level, the worm gear thermal management challenge becomes the limiting factor long before the torque rating is reached.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

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Field Reports<\/h2>\n
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O<\/div>\n
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Olav H. \u2014 Marine Crane System Engineer<\/div>\n
Verified Purchase \u00b7 Haugesund, Norway \u00b7 April 2026<\/div>\n<\/div>\n
\u2605\u2605\u2605\u2605\u2605<\/div>\n<\/div>\n

8-tonne SWL knuckle-boom crane on a platform supply vessel. The 402W2 at ratio 28 paired with a 45 cc\/rev Rexroth A2FM motor and dual counterbalance valves. The brake-free design was the correct choice for this application \u2014 our DNV-certified hydraulic circuit provides motor brake plus counterbalance hold, and adding a third brake inside the gearbox would have required re-certification of the entire braking system. The 402W2 passed the DNV type approval survey without any additional documentation beyond the standard product data sheet and material certificates. Clean and simple.<\/p>\n<\/div>\n

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C<\/div>\n
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Chris W. \u2014 Offshore Davit Manufacturer<\/div>\n
Verified Purchase<\/div>\n<\/div>\n
\u2605\u2605\u2605\u2605\u2605<\/div>\n<\/div>\n

Free-fall lifeboat davit recovery winch for an FPSO project. The winch only operates in the hoisting direction \u2014 recovering the 6.5-tonne lifeboat after a drill deployment. The 402W2 at ratio 18 with a 63 cc\/rev variable-displacement motor gives us 15 m\/min recovery speed at full load. The brake-free design was specifically requested by the platform operator because their maintenance procedure treats gearbox-internal brakes as an inspection item that requires drum removal \u2014 which on an FPSO means a crane and three-day work permit. No internal brake means no brake inspection means no drum removal. The counterbalance valves provide all holding functions and are accessible from outside the drum housing.<\/p>\n<\/div>\n

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B<\/div>\n
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Ben K. \u2014 Construction Hoist OEM Designer<\/div>\n
Verified Purchase \u00b7 June 2026<\/div>\n<\/div>\n
\u2605\u2605\u2605\u2605\u2606<\/div>\n<\/div>\n

2.5-tonne materials hoist for high-rise construction. The 402W2 at ratio 25 with a motor-mounted electromagnetic brake (primary) and a drum calliper brake (secondary). Mechanically the drive is solid and the hoisting speed control through the variable-displacement motor is smooth. The 4-star reflects a documentation issue: the product data sheet lists “external braking system required” but does not specify the MINIMUM brake holding torque needed at the drum for various load scenarios. We calculated it ourselves from the torque and ratio, but a pre-calculated table showing “at X load on Y drum PCD, minimum external brake torque = Z” would have accelerated our safety case submission by a week.<\/p>\n<\/div>\n<\/div>\n<\/section>\n<\/div>","protected":false},"excerpt":{"rendered":"

The EP-402W2 is the first two-stage winch drive planetary gearbox in the Korea Ever-Power catalogue: 4,000 Nm across a multi-ratio range of 12.4 to 37.1 at up to 3,500 rpm input. It is also the first winch drive model that ships without an integrated parking brake \u2014 a deliberate design choice for hoisting systems where the braking function is handled entirely by the hydraulic motor, external calliper brakes, or counterbalance valves in the circuit. This architectural decision saves weight, eliminates brake disc maintenance, and allows the winch system designer to specify the braking method that matches the application standard \u2014 not the one built into the gearbox.<\/div>","protected":false},"featured_media":940,"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-931","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\/ja\/wp-json\/wp\/v2\/product\/931","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/comments?post=931"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/media\/940"}],"wp:attachment":[{"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/media?parent=931"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/product_brand?post=931"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/product_cat?post=931"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ja\/wp-json\/wp\/v2\/product_tag?post=931"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}