615L3 Planetary Wheel Drive Gearbox Reducer — 3-Stage

The EP-615L3 is where the planetary wheel drive gearbox concept reaches its practical upper boundary. At 60,000 Nm — 33% more torque than the 613L3 and 3.5 times the output of the mid-range 607 — the 615L3 serves machines so large that a single wheel drive failure doesn't just stop one vehicle. It blocks a haul road, delays a vessel loading, or halts a once-in-a-decade heavy lift operation. The engineering at this level is about eliminating the possibility of that failure, not just reducing its probability.

The 1,000 Nm multi-disc parking brake is unique to the 615L3 — no other model in the catalogue offers it. Through the 108:1 gear ratio, this brake produces 108,000 Nm of holding torque at the wheel: enough to hold a 300-tonne mining truck on a 25% grade with the engine off and no hydraulic pressure anywhere in the system. The Viton-sealed, carburised-steel, 480 kg housing is designed for 20,000-hour intervals between overhauls under the most severe continuous-duty conditions the mining and heavy transport industries can impose.

Four 615L3 units add 1,920 kg to the vehicle unsprung mass — almost two tonnes that must be accounted for in the axle load calculation. On mining trucks where axle load limits are imposed by haul road structural capacity, this 1,920 kg directly reduces the payload capacity by the same amount. The vehicle chassis designer must optimise the axle structure to carry the 615L3 mass without exceeding the road bearing capacity or the tyre load rating.

The mounting flange bolts carry not only the output torque reaction (60,000 Nm tangential) but also the 480 kg gravitational load (4,709 N downward) plus the dynamic loads from road surface impacts. The combined bolt loading — torque, shear, and bending — requires a mounting flange at least 30% thicker than what the torque reaction alone would demand. Use Grade 10.9 or 12.9 bolts with Nordlock washers or equivalent anti-vibration locking.

On suspension-equipped vehicles, the 480 kg per corner is significant unsprung mass. Higher unsprung mass reduces the suspension ability to maintain tyre contact on rough surfaces, which affects both traction and component fatigue. Mining trucks operating on poorly maintained haul roads should specify the heaviest available suspension damping to counteract the 615L3 mass contribution. On rigid-frame (non-suspended) vehicles, the issue is instead transmitted vibration to the chassis — address with elastomeric mounting pads between the axle housing and the frame.

A 480 kg unit requires a crane with minimum 1,000 kg capacity at the working radius. On remote mining sites, the service crane must be able to reach the wheel hub while the truck is jacked or supported on stands. A dedicated lifting cradle — matched to the 615L3 housing geometry and supplied by Korea Ever-Power on request — reduces the two-crane-plus-four-person replacement to a one-crane-plus-two-person operation, saving approximately 2 hours per unit changeover.

Ultra-Class Mining Haul Trucks (100-150 t Payload)

The largest diesel-hydraulic haul trucks in production mining. Six or eight 615L3 units per truck producing a combined tractive effort of 360,000-480,000 N — enough to climb a 25% loaded haul road at 3-5 km/h with a 200-300 tonne GVW. The 1,000 Nm brake holds the fully loaded truck on any grade the haul road surface can physically support. These trucks operate 20-22 hours per day, 350 days per year, in conditions where a wheel drive failure blocks the primary revenue-generating haul cycle.

Rubber-Tyred Gantry Cranes (RTG)

RTG cranes with 40-65 tonne lifting capacity that travel on pneumatic tyres along container stacking rows in port terminals. Each RTG uses 8 wheel drives (4 per gantry leg) to propel a 120-160 tonne crane structure along the stacking lane at 2-4 km/h under load. The 615L3 at ratio 108 provides controlled creep speed and precise positioning for container stacking accuracy. The slewing drive planetary gearbox handles the crane trolley and hoist rotation on the same port equipment platform.

Ultra-Heavy SPMT Configurations (600-1,000 t)

The heaviest self-propelled modular transporter configurations — carrying offshore platform modules, nuclear power plant components, and complete bridge superstructures. Where the 613L3 at 45,000 Nm serves loads up to 600 tonnes, the 615L3 extends the SPMT capability to 1,000 tonnes by providing 33% more torque per wheel position. With 32-48 wheel drives per trailer configuration, the total available tractive force reaches 960,000-1,440,000 N — enough to move the heaviest indivisible loads manufactured anywhere in the world.

Why is the 615L3 efficiency 93% instead of 94% like the 613L3?

The 615L3 uses larger-module gears with wider face widths to carry the additional torque. Larger gears have proportionally more sliding contact at the tooth flanks relative to rolling contact, which generates slightly more friction heat per mesh cycle. The three-stage configuration compounds this effect across six mesh interfaces. At 93%, the 615L3 wastes approximately 4.5 kW at full load (60,000 Nm at 2,000 rpm output via 108:1 ratio = 64.4 kW input) — compared to 3.8 kW for the 613L3 at the same operating conditions. The absolute difference is modest; the percentage reflects the fundamental physics of scaling gear transmissions.

What happens if the application needs more than 60,000 Nm per wheel?

The 615L3 is the upper limit of the planetary wheel drive gearbox range. Above 60,000 Nm per wheel, the application transitions to diesel-electric drive with hub-mounted electric wheel motors, which can deliver 80,000-150,000 Nm per wheel. This is the architecture used by the largest class of mining haul trucks (200-400 tonne payload). For applications between 60,000 Nm and the electric wheel motor range, consider dual-motor configurations driving a single 615L3 through a combining gearbox — contact Korea Ever-Power for custom engineering consultations.

How does a planetary wheel drive at 60,000 Nm compare to a diesel-electric wheel motor?

The 615L3 (hydraulic motor + planetary gearbox) weighs approximately 480 kg plus a 60-80 kg hydraulic motor = 540-560 kg total. An equivalent electric wheel motor weighs 1,500-2,500 kg. The hydraulic system is lighter, mechanically simpler, and less expensive. The electric system offers regenerative braking, more precise speed control at any point in the torque range, and the ability to scale to torques the hydraulic architecture cannot reach. Below 60,000 Nm and on machines that do not need regen braking, the hydraulic-planetary approach is the engineering optimum.

What oil volume does the 615L3 require and what are the sampling requirements?

Approximately 12-15 litres. Oil sampling every 500 hours is mandatory — not optional. Change interval: 1,500 hours in mining, 2,000 hours in port operations. First change at 250 hours. Use API GL-5 SAE 80W-90. At this torque class, a wheel drive failure on a 200+ tonne truck costs the mine an estimated USD 5,000-15,000 per hour in lost production. The total annual cost of oil sampling across an 8-unit fleet is approximately USD 2,000-3,000. The return on investment for oil-based predictive maintenance is measured in orders of magnitude, not percentages.

Can the 615L3 housing be used as a structural member in the axle design?

No. The 615L3 housing is designed to carry torque loads and support its own weight. It is not designed to carry vehicle suspension loads, steering forces, or crash loads. The vehicle axle structure must provide an independent load path from the wheel rim to the chassis that does not pass through the gearbox housing. Any bending moment applied to the gearbox housing through the axle structure will distort the bearing bores and cause accelerated bearing failure. Ensure a rigid, concentric mounting interface that transmits only torque tangentially to the output flange.

What overhaul interval applies to the 615L3 at maximum continuous duty?

Target first overhaul at 18,000-20,000 hours with full maintenance compliance. The carburised alloy steel gears at HRC 58-62 are not typically the life-limiting components. Output seals (10,000-15,000 hours in dusty mining), brake disc stacks (15,000-25,000 hours), and output bearings (20,000-30,000 hours L10) define the overhaul trigger. An overhaul consists of full disassembly, inspection, bearing and seal replacement, re-assembly with factory preload, and dynamometer load test. Typical overhaul cost is 40-50% of new unit price. Overhaul turnaround: 4-6 weeks from receipt at the factory.

Prototype evaluation on our 120-tonne payload mining truck. Eight 615L3 units, 1,000 Nm brake option. The truck climbs our 23% test grade fully loaded at 4.8 km/h — matching the performance specification within 2%. The 1,000 Nm brake holds on the same grade with engine off and all hydraulic pressure dumped. We measured brake release at 28 bar, which is comfortably within our pilot circuit capacity. Oil analysis at 3,000 hours (prototype accelerated test) showed iron particles within threshold. We have signed the production contract for 48 units covering the first six trucks.

RTG crane fleet, 16 units on two cranes, 615L3 with 800 Nm brake. The cranes travel along 400-metre stacking lanes and position containers to within 50 mm tolerance. The 615L3 creep speed smoothness at 0.5 km/h under a loaded spreader is noticeably better than the previous Japanese-brand drives — the operators say the crane "doesn't jerk at the end of travel." Oil changes every 2,000 hours, 18 months in service on the first crane, zero unscheduled maintenance events. We are ordering a third crane with the same specification.

48 units on SPMT trailer sets for an 850-tonne offshore topside module transport. The lift went perfectly — transport distance 2.4 km from fabrication hall to quay, 5 hours at 0.4 km/h average. The 615L3 provided smooth, controllable power throughout, including a 3% cross-slope section where the hydraulic system had to compensate for the lateral weight shift. The 4-star rating is purely about logistics: the 480 kg per unit meant we needed a dedicated 20-foot container and forklift at the port to handle the 48-unit delivery. The lighter 613L3 units on our other trailer sets can be stacked on pallets and moved by hand truck. At this weight class, the handling logistics become a project management consideration. Product performance was flawless.