HET Gear® gearboxes

The vacuum turbo gear units from RENK-MAAG GmbH are designed and constructed according to the latest findings and methods of gear unit technology. Turbo gear units from RENK-MAAG GmbH can transmit a power of up to 120/180 MW and serve as the key component of an energy production system or as compressor drive unit (such as those used for air separation, gas compression, in the chemical and petrochemical industries, the refining of raw materials, steelworks, and in the process industry).

While the toothing of standard gear units is surrounded by a medium similar to air in the gearbox housing, the interior is placed under a vacuum in the case of the patented HET Gear® (high efficiency technology gearbox), thereby reducing the loss of power by up to 60%. This improves the carbon footprint, the financial balance, and the durability of the components as well, because they run cooler.

RENK-MAAG GmbH, which invented the vacuum gear unit technology, has acquired many years of experience and reduced the complexity of the gear unit to the minimum. As a result, it is possible to smoothly switch between the vacuum and standard mode and back without interrupting production. And the MTBF is even higher in comparison to standard gear units.

The gear unit housing and the customer’s connecting dimensions can either conform to RENK’s standards or be adapted completely to the requirements of the customer. This is of crucial importance when it comes to replacing third-party products in particular.


HET Gear® gearboxes

Highest efficiency

Up to 99.3 % at 90 MW

Output range from 15 up to 180 MW


Tooth-system-speed from 120 up to > 180 m/s


Technical data

Power transfer:
0.25–180 MW
Up to 99.3%
Center distance:
150 mm to over 2,000 mm
Up to 63,000 rpm
Pitch line velocity:
Up to 180 m/s
Transmission ratios:
1–10 (single- or multi-stage)
Housing design:
Welded, cast
Single-helical with and without thrust collar, double-helical
Drive variants:
Synchron engine, asynchronous engine, gas turbine, expander turbine, energy recovery with MS-coupling


Other products

Vacuum gear units


The sophisticated RENK etaX® technology is currently the latest, most economical and mature turbo gear unit concept in the 30–180 MW range.

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Power generation

Power plant

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