ZR19 Slewing Drive Planetary Gearbox — Right-Angle Bevel-Planetary, 2-5 Stage

ال EP-ZR19 slewing drive planetary gearbox occupies a unique position in the ZR slewing drive series: its specification table shows 20,600 Nm continuous output torque and 45,000 Nm peak — 25% and 7% higher than the published headline figures of 16,500 Nm and 42,000 Nm respectively. This margin exists because the ZR19 internal bevel input pair (R16, R10, R06 sub-variants) is sized conservatively for this frame, delivering actual performance that comfortably exceeds the catalogue promise.

With 47 discrete gear ratios across 2-stage through 5-stage configurations, the ZR19 covers a ratio range from 13.29 to 1,808. Only two torque tiers exist (20,600 Nm and 17,200 Nm), compared to the three-tier de-rating structure of the adjacent ZR16 — meaning a higher proportion of the ZR19 ratio table delivers full-rated torque.

Wind Turbine Yaw Systems (1-3 MW Class)

Megawatt-class wind turbines with rotor diameters of 60-100 metres require nacelle yaw torques of 12,000-20,000 Nm per drive unit. The ZR19 3-stage at ratios 43:1-70:1 provides the torque-speed combination these yaw mechanisms demand, with the 45,000 Nm peak rating absorbing storm-load transients. Typical MW-class yaw systems use 4-8 ZR19 units equally spaced around the tower-top yaw bearing, each driven by a 7.5-15 kW electric motor through a VFD.

Tunnel Boring Machine Auxiliary Drives

TBM segment erector rotation, thrust cylinder ring positioning, and shield articulation mechanisms generate sustained slewing torques in the 15,000-20,000 Nm range under extremely confined and wet conditions. The ZR19 4-stage at ratios 110:1-280:1 provides the controlled low-speed rotation these mechanisms require, while the IP67 sealed housing resists the groundwater, bentonite slurry, and aggregate abrasion present inside the TBM shield.

Heavy Industrial Positioners and Rotary Kilns

Large-diameter rotary kiln support rollers, cement plant clinker cooler rotation drives, and heavy welding positioners for pressure vessel fabrication require sustained high torque at very low output speeds (0.1-5 rpm). The ZR19 5-stage at ratios 382:1-1,808:1 covers this speed range directly from a standard 4-pole IEC motor without any external reduction stage, simplifying the drive package and reducing the number of potential failure points.

Handling and Lifting

Use the cast lifting eye-bolts only. Never lift by the output shaft, input shaft, or brake housing. Minimum lifting capacity 400 kg (1.5x safety factor). Secure the unit horizontally during crane transport to prevent the output shaft from acting as a pendulum that could damage the output seal. Use nylon slings or padded chains to avoid scratching the housing coating.

Short-Term Storage (Under 6 Months)

Store indoors in a dry, ventilated area. Leave the factory oil fill in place — it provides corrosion protection for the internal gear and bearing surfaces. Cover the input and output shaft openings with the factory-fitted protective caps. Do not remove these caps until the moment of motor or pinion installation. Rotate the input shaft by hand 10 turns every 30 days to redistribute the oil film on bearing surfaces.

Long-Term Storage (6-24 Months)

Apply VCI (Volatile Corrosion Inhibitor) spray to all exposed machined surfaces (shaft ends, flange faces, bolt holes). Seal the breather valve port with a VCI-treated plug. Wrap the entire unit in VCI barrier paper or film. Store on a wooden pallet in a temperature-controlled warehouse (5-40 deg C, under 70% relative humidity). Perform the 30-day shaft rotation even during long-term storage.

Pre-Installation Inspection

Before mounting, verify: oil level is at the correct mark, no visible seal damage or oil weep, shaft rotates freely by hand without grinding or catching, breather valve is clear, and mounting flange surface is free of rust or impact damage. If the unit has been stored for more than 12 months, drain and refill the oil before commissioning. Contact our engineering team for guidance on units stored beyond 24 months.

How does the ZR19 compare to the ZR24 for the same application?

The ZR19 (20,600 Nm actual) and ZR24 (25,000 Nm actual) overlap in the 17,000-20,600 Nm torque range. The ZR19 offers 47 ratios with a maximum of 1,808:1, while the ZR24 provides 24 ratios reaching 4,347:1. If your required ratio is below 1,808, the ZR19 likely provides a closer match with a more compact frame. If ultra-high ratios above 1,808 are needed, the ZR24 is the only option. For torque requirements above 20,600 Nm continuous, the ZR24 is required regardless of ratio.

How many ZR19 units are needed for a 2 MW wind turbine yaw system?

A 2 MW turbine with an 80-90 metre rotor diameter typically requires a total nacelle yaw torque of 80,000-120,000 Nm (including storm load safety factor). At 20,600 Nm per unit, this requires 4-6 ZR19 drives equally spaced around the yaw bearing. The exact number depends on the turbine manufacturer specified safety factor, the site wind class (IEC I, II, or III), and whether the yaw system must meet storm endurance without the yaw brake. Provide the turbine model and site wind data for a verified recommendation.

Why is the ZR19 limited to 2,500 rpm instead of 3,500 rpm like the smaller models?

The ZR19 bevel input stage uses larger-diameter bevel gears than the ZR01-ZR16 to achieve the higher torque capacity. Larger gear diameters mean higher peripheral speed at the tooth mesh. The 2,500 rpm limit ensures the bevel tooth peripheral speed stays within the design threshold for acceptable noise, heat generation, and bearing load at the bevel stage. In practice, most ZR19 applications use 4-pole motors at 1,450-1,800 rpm, well below the 2,500 rpm limit.

Can the ZR19 be used inside a tunnel boring machine where temperatures exceed 40 deg C?

Yes. The standard operating range is -40 to +80 deg C ambient. TBM shield interiors typically reach 35-55 deg C. At sustained ambient above 40 deg C, de-rate the thermal power (Pt) by 2% per degree. For a ZR19**4 at 50 deg C ambient, the effective Pt(M) becomes approximately 10.0 kW (versus 12.5 kW at 40 deg C). Verify that the motor input power at your duty cycle does not exceed this adjusted value. If it does, specify the fan-cooled shroud option or increase the stage count (lower Pt but constant torque).

We maintain 22 turbines across two wind farms and have been replacing yaw drives with ZR19**3 units over the past 18 months. The retrofit is straightforward — the mounting interface matches the OEM bolt pattern with a standard adapter ring. Performance at -22 deg C winter operation has been reliable with the VG 150 oil specification. We installed vibration sensors on the first four replacements per the manual and so far the trending data looks stable. The biggest practical benefit is having one part number for all 22 turbines instead of the three different OEM models we were previously stocking.

Segment erector drive on a metro tunnel project. The unit operated inside the TBM shield for 14 months at approximately 45 deg C average ambient. We performed the oil analysis at every oil change and the particle counts stayed within normal limits throughout. The IP67 seal has held up in an environment where everything gets coated in bentonite slurry within days. No complaints.

Rotary kiln support roller drive, ZR19**5 at 973.56 ratio. The drive replaced a chain-and-sprocket arrangement that required re-tensioning every two weeks in the kiln house dust environment. The ZR19 has been running for 10 months maintenance-free other than the scheduled oil change. One observation: we received the unit with the breather valve assembled but not the VCI storage caps, so the exposed shaft ends had light surface oxidation after sitting in our warehouse for three months before installation. It cleaned up without issue but better packaging for long storage would be an improvement.