ZR16 Slewing Drive Planetary Gearbox — Right-Angle Bevel-Planetary, 2-5 Stage

The EP-ZR16 is the most versatile frame in the ZR slewing drive series. With 61 discrete gear ratios spanning five stage configurations (2-stage through 5-stage), the ZR16 provides the highest probability of an exact ratio match for any application in the 10,500-16,580 Nm torque class. Where other models force engineers to compromise between the closest available ratio and a larger motor, the ZR16 offers enough density of choice that the optimal motor-gearbox combination can almost always be achieved.

At the lower ratios, continuous torque reaches 16,580 Nm — 22% above the headline 13,580 Nm specification — because the shorter gear mesh path reduces cumulative losses. The 5-stage configurations extend the ratio range to 4,438:1 for ultra-low-speed positioning applications, with 26 options in this stage count alone providing fine-grained speed selection that no competitor in this torque class can match.

The housing surface acts as the heat sink. Effective for intermittent duty (S3, ED under 40%) or continuous duty where motor input power stays below Pt(M). The finned housing design of the ZR16 provides approximately 15% more surface area than a smooth-walled housing of the same volume.

An externally-mounted fan shroud attaches to the housing and forces air across the heat dissipation fins. Increases Pt by approximately 30-50% over natural convection. Suitable for continuous-duty applications (S1) where motor input power exceeds Pt(M) but stays below Pt(F). Powered by the motor shaft fan or a separate electric fan motor.

For applications where even fan cooling is insufficient (enclosed environments, tropical climate, 24/7 S1 duty), an external oil circulation system pumps the gear oil through a heat exchanger and returns it at controlled temperature. This can double the effective Pt versus natural convection. Requires additional plumbing ports in the housing, which are factory-machined on request.

ISO 9001:2015 certified manufacturing with full material traceability

Harbour Mobile Cranes (25-40 Tonne)

Rubber-tyred gantry (RTG) and harbour mobile cranes in the 25-40 tonne lifting class generate continuous slewing torques of 10,000-15,000 Nm at full jib extension. The ZR16 3-stage at ratios 38:1-56:1 provides the speed-torque balance for efficient cargo cycling, while 61 ratio options allow precise matching to the crane hydraulic system for minimum energy loss per cycle.

Large Drilling Rigs — Rotary Table and Top Drive

Oil and gas drilling rigs, water well boring machines, and geotechnical drilling equipment require high torque at controlled low speeds for string rotation and mast positioning. The ZR16 4-stage and 5-stage configurations at ratios 200:1-1,300:1 deliver the creep-speed rotation these operations demand, with the IP67 sealing protecting against drilling mud, cuttings, and formation water present at every rig site.

Steel Mill Ladle Cars and Transfer Turntables

Steelworks ladle transfer cars, caster turntables, and bloom handling positioners operate in extreme heat, scale dust, and intermittent water spray from cooling systems. The ZR16 5-stage at ultra-high ratios (2,000:1-4,438:1) provides the sub-1-rpm controlled rotation these heavy positioners require, while the QT600-3 ductile iron housing withstands the radiant heat and the right-angle configuration keeps the motor clear of the thermal zone.

How do I choose between the ZR16 and the ZR10 for the same torque requirement?

The ZR10 (11,500 Nm rated, 41 ratios) and ZR16 (13,580 Nm rated, 61 ratios) overlap in the 10,500-11,500 Nm output torque range. If your required continuous torque falls in this overlap zone, the ZR10 is more compact and cost-effective. If the required ratio is only available in the ZR16 table (particularly 5-stage ratios above 465:1), or if you need the higher peak torque capacity (36,500 Nm versus 24,500 Nm), the ZR16 is the correct choice.

Can the ZR16 operate in a steel mill environment with ambient temperatures above 60 deg C?

Yes, with modifications. Above 60 deg C ambient, the oil change interval must be halved (2,000 hours instead of 4,000), and the thermal power rating must be de-rated by 2% per degree above 40 deg C. For sustained ambient above 70 deg C, specify the high-temperature seal kit (FFKM seals rated to 200 deg C continuous) and ISO VG 460 PAO synthetic oil. External heat shielding is recommended if the housing is exposed to direct radiant heat from molten metal.

With 61 ratio options, how do I narrow the selection?

Start with the target output speed: divide the motor speed by the desired output speed to get the target ratio. Filter the table for the closest match. Then verify: (1) the continuous torque at that ratio meets the application requirement with the appropriate service factor, (2) the thermal power at the corresponding stage count accommodates the motor input power, and (3) the stage count fits the physical installation envelope. If two ratios are equally close, choose the one with higher thermal capacity (fewer stages).

What is the typical lead time for a ZR16 with a custom output pinion?

Standard lead time for the ZR16 with a custom-ground output pinion matched to your slewing ring tooth profile is 6-8 weeks from order confirmation. The pinion grinding adds approximately 1 week to the standard gearbox manufacturing cycle. If you provide the slewing ring drawing at the time of enquiry rather than after order, we can begin pinion engineering in parallel with the commercial process and reduce the overall timeline.

We specified ZR16**3 at 41.77 ratio for a new harbour mobile crane platform. The selection process was straightforward — with 61 ratios, we found an exact match for our hydraulic circuit rather than the usual compromise of rounding to the nearest available option. The calculated motor displacement matched the actual measured displacement within 2%, which meant the system ran at the predicted temperature from day one. Very unusual to get that level of agreement between calculation and field result.

Ladle car turntable in a melt shop, ZR16**5 at 1,087 ratio. The unit handles the 280 deg C ambient near the caster without issues when we installed the heat shield. The high-temperature seal option works. The 4-star rating is because the external oil circulation cooling that we needed for 24/7 operation required a custom port machining that added 3 weeks to the lead time. If the cooling ports were a standard option it would have been 5 stars.

Mast rotation drive on a large-diameter bored piling rig. Previously using a multi-stage chain reduction off a hydraulic motor which required constant re-tensioning. The ZR16 4-stage at 215.21 ratio replaced the entire chain drive assembly with one sealed unit. Chain tensioning maintenance went from weekly to zero. The rig downtime reduction alone justified the investment within the first two months of operation.