Vibration switches and sensors are utilized to monitor fan vibrations and for emergency cut-outs in case of fan blade ruptures or drive train failures.

The thresholds of vibration switches are adjustable. Resets are done manually after the switches’ tripping and the following trouble shooting.

Vibration sensors have a usual measuring range from 0 to 24 mm/s and supply an output from 4 to 20 mA. Emergency cut-outs are generated in the process control system.

Oil piping is installed from the gearboxes to the outside of the fan stacks to control the gear oil levels. There, oil level indicators allow visual checks. At the same time, oil can be changed there without the danger of polluting the cooling water.

The oil flow of bevel-spur gearboxes is controlled with oil flow and pressure switches.

Additional instruments like oil temperature transmitters and oil level switches are available.