400W1 Winch Drive Planetary Gearbox Reducer

400W1 — Where the Winch Drive Catalogue Begins

UN winch drive planetary gearbox does something no other gearbox type in the catalogue does: it sits inside the cable drum, rotating with it. The housing flanges bolt to the drum cheek plates, the output shaft becomes the drum axis, and the motor drives the input from the centre. From outside, all you see is a drum turning on its shaft. Inside, a planetary gear train is doing the work — converting high-speed, low-torque motor rotation into the slow, powerful drum rotation that lifts loads against gravity.

The EP-400W1 is the lightest unit in this range: 870 Nm output torque, a single planetary stage at 6.09:1, and an integral 130 Nm spring-applied parking brake that holds the load in the air when the motor stops. At 45 kg and 96% efficiency, it serves the winches where compact size and high efficiency matter more than raw pulling power — and where the FEM M5 duty classification confirms the drive is rated for sustained, repetitive lifting cycles rather than occasional use.

Determine the line pull

The maximum force in the cable at the first layer on the drum. For a simple vertical lift: line pull = load weight x gravity x safety factor. For a 500 kg personnel hoist with a 4:1 safety factor: line pull = 500 x 9.81 x 4 = 19,620 N. For angled pulls, multiply by the fleet angle correction factor.

Measure the drum pitch circle diameter

The PCD is the diameter measured to the centre of the cable on the first (innermost) layer. PCD = drum barrel diameter + cable diameter. For a 200 mm barrel with 10 mm cable: PCD = 210 mm, radius = 0.105 m. The first layer produces the highest torque because the lever arm is shortest — all subsequent layers increase the PCD and reduce the effective line pull per unit of gearbox torque.

Calculate the required gearbox torque

T = line pull x PCD radius. For the example above: T = 19,620 x 0.105 = 2,060 Nm. This exceeds the 400W1 rating of 870 Nm — step up to the 401W1 (1,300 Nm) or 402W2 (4,000 Nm) depending on the required safety margin. If the calculation yields under 870 Nm, the 400W1 is the correct model.

The Housing Rotates

The 400W1 housing flanges bolt to the drum cheek plates. When the motor drives the input shaft, the ring gear (fixed to the housing) reacts against the planet carrier, and the housing — along with the entire drum — rotates around the stationary output shaft. The drum and gearbox are one rotating assembly. The motor and its hydraulic connections remain stationary, feeding power through a rotary interface at the shaft centre.

The Output Shaft Is Fixed

The output shaft of the 400W1 does not rotate — it is the axle that the drum pivots around. This shaft is anchored to the winch frame structure and carries the full weight of the drum plus cable plus load as a bending load. The shaft diameter and bearing arrangement must be sized for this combined load, not just the torque. Provide the maximum cable capacity and drum weight to Korea Ever-Power engineering for shaft load verification.

The Brake Holds the Load in the Air

The 130 Nm spring-applied brake engages automatically when hydraulic pressure is removed — holding the drum (and the suspended load) in position. This is a safety-critical function: if the motor loses power while a load is suspended, the brake must prevent uncontrolled descent. The 130 Nm brake through the 6.09 ratio produces approximately 792 Nm of holding torque at the drum — verify that this exceeds the torque generated by the maximum suspended load at the drum PCD radius.

Oil Stays Inside While Rotating

The oil-bath lubrication system must function with the housing rotating continuously — not stationary like a wheel drive. The 400W1 seal arrangement is specifically designed for rotating-housing duty, with the output shaft seal running against the stationary shaft and the input seal accommodating the relative rotation between the motor and the drum. Standard wheel drive seals are not interchangeable — always order seals designated for the W (winch) series.

Construction Personnel Hoists

Small capacity personnel and material hoists on construction sites, lifting 200-400 kg at 10-20 m/min through 2-6 floors. The 400W1 single-stage provides the compact diameter needed to fit inside the narrow drum housings these hoists use, and the 130 Nm fail-safe brake ensures the platform holds at any floor level when the operator releases the control lever. The FEM M5 duty rating covers the 200-400 cycle-per-day usage profile of a busy construction site.

Marine Davits and Lifeboat Winches

Davit winches for lifeboat launching and recovery on offshore platforms, workboats, and small vessels. The 400W1 at 45 kg meets the space and weight constraints of marine davit installations, and the sealed oil-bath housing resists the salt spray, humidity, and deck wash water that destroy open-gear winch mechanisms within months. The -20 to +80 deg C range covers North Sea to tropical waters without seal modification.

Utility Cable Tensioners and Small Cranes

Cable tensioning winches for power line stringing, fibre optic installation, and pipeline pull-in operations. The controlled, low-speed output (maximum 25 rpm) provides the precise cable tension management these operations demand, and the single-stage 96% efficiency means less hydraulic power is wasted as heat during the sustained, low-speed pulling cycles that cable tensioning involves. The track drive planetary gearbox propels the cable-stringing crawler on the same utility installation project.

What is the difference between a winch drive and a wheel drive planetary gearbox?

A wheel drive mounts on a stationary axle and rotates the wheel hub. A winch drive mounts inside a rotating drum and turns with it — the housing rotates, the output shaft stays fixed. The seal arrangement, bearing loading, and lubrication design are different because the gearbox is in continuous rotation during operation rather than stationary. Additionally, the winch drive must hold a suspended load in the air via the parking brake — a safety-critical function that wheel drives do not perform in the same way.

What does FEM M5 mean and why does it matter for winch drive selection?

FEM (Federation Europeenne de la Manutention) classification M5 defines a medium-heavy duty cycle: the gearbox is rated for sustained repetitive operation at loads between 50-100% of rated capacity for up to 1 million load cycles over its design life. This is the standard for production winches that operate hundreds of cycles per day. Lower classifications (M1-M4) apply to occasional-use or light-duty winches; higher classifications (M6-M8) apply to continuous heavy-duty crane hoists. The 400W1 at FEM M5 is correctly rated for construction hoists and marine davits that operate at sustained duty without the extreme cycle counts of a steelworks crane.

Is the 130 Nm brake sufficient to hold a load in the air during a power failure?

The 130 Nm brake acts on the input shaft and is multiplied through the 6.09 ratio to produce approximately 792 Nm of holding torque at the drum. Whether this is sufficient depends on the load and the drum PCD. For a 300 mm PCD drum, the maximum holdable line pull is 792 / 0.15 = 5,280 N (approximately 540 kg). If the maximum suspended load exceeds this, the brake is undersized — step up to the 401W1 with its 270 Nm brake (producing approximately 1,674 Nm at the drum). For personnel hoisting applications, regulations typically require a static brake holding capacity of at least 1.5x the rated load — verify this margin before commissioning.

Can a winch drive planetary gearbox lower a load by reversing the motor?

Yes, but with careful hydraulic circuit design. During lowering, gravity drives the load downward, which back-drives the drum and gearbox, pushing oil back through the motor. Without a counterbalance valve in the motor circuit, the load will descend uncontrollably. The counterbalance valve meters the return oil flow, controlling the descent speed. The 400W1 gears handle reverse-direction torque identically to hoisting torque — the planetary gear train is mechanically symmetrical. The critical design element is the hydraulic circuit, not the gearbox.

How does cable layer build-up on the drum affect the winch drive torque requirement?

Each additional cable layer increases the effective drum diameter (PCD), which increases the lever arm and therefore the torque required to lift the same load. The torque on the first layer is load x PCD_1 / 2. On the third layer, the PCD is approximately PCD_1 + 4 x cable diameter, producing proportionally higher torque. The 400W1 must be sized for the OUTERMOST layer (highest torque), not the first layer — even though the first layer produces the highest line pull per unit of gearbox torque. Always calculate at the maximum wrapped diameter.

Can I use a réducteur à vis sans fin instead of a planetary gearbox for a winch application?

A worm gear reducer at high ratios (above 30:1) provides inherent self-locking, which can eliminate the need for a separate parking brake. However, at 40-65% efficiency, the worm wastes 35-60% of the motor input as heat — requiring a much larger motor and producing significant thermal management challenges inside a sealed drum. The 400W1 at 96% efficiency requires a motor producing only 4% more power than the theoretical minimum, whereas a worm gear would require 54-150% more. For any winch operating more than a few cycles per day, the planetary gearbox with a separate brake is the more energy-efficient, cooler-running, and ultimately lower-cost solution.

Personnel and materials hoist on a 14-storey residential tower. The 400W1 has run approximately 250 cycles per day for 9 months — lifting an average of 300 kg of materials and crew up to 42 metres. No issues with the drive, the brake engagement is crisp and consistent, and the oil has stayed clean at the 2,000-hour sample. The previous worm-gear winch on the same hoist required a motor twice the size and ran noticeably hotter. The 400W1 solved both problems.

Lifeboat davit winch on a North Sea supply vessel. The 400W1 has survived 18 months of continuous salt spray exposure with the original seals intact. We launch and recover the rescue boat twice weekly for drills plus the mandatory annual certification test under full load. The sealed housing was the primary reason for selecting a planetary drive over the open-gear davit winch the vessel was originally fitted with — the open gears corroded within one season despite weekly greasing. The 400W1 has required zero maintenance other than the oil change at 12 months.

Cable tensioner for fibre optic line stringing. The 400W1 provides smooth, controllable tension at 5-15 m/min pulling speed, which is exactly the range our fibre splice technicians need. The 4-star rating is because we initially mis-calculated the required torque using the first-layer drum PCD instead of the outer-layer PCD — and the 400W1 was undersized for the last 3 layers of cable. We should have ordered the 401W1 from the start. Not a product issue — purely a user sizing error. Ever-Power technical support caught the mistake during a follow-up call and arranged the swap promptly.