FLENDER Gear Units for Wet Cooling Towers


The trickling of water in wet cooling towers is selectively controlled by the cooling tower drive. Usually two-stage bevel-helical gear units are used in addition to the motor. FLENDER gear units are specially designed for use in wet and hybrid cooling towers. As a major design criterion, the fan speed is optimized by using the most diverse transmission ratios. If any special transmission ratios are needed, these can also be provided. The resulting reactive forces of the fan can be absorbed directly by the gear unit.

As the motor is situated outside the cooling tower, the gear unit located in the middle is driven externally by a long composite coupling which is also included in the Siemens product portfolio.

Technical Data


Bevel helical gear unit



Gear stages


Power ratings

up to 2,000 kW

Transmission ratios

i = 5 to 22.4

Nominal torques

3,000 to 97,500 Nm

Mounting positions



  • Low noise emission thanks to torsionally rigid housing

  • Variable lengths of output bearing arrangements for various fans (adapted to the fan profile)

  • Maximum operational reliability through solid housing, bearing reinforcement, grease slinger on the fan shaft

  • Additional cooling by fan on the input shaft

  • Long service life thanks to optimized design and use of high-quality materials

  • Complete drive train from a single source


Power generation industry, for example:

  • Biomass power plants

  • Gas-fired power plants

  • Nuclear power plants

  • Coal-fired power plants

  • Waste incineration plants

  • Oil-fired power plants