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ENERCON E-40 Operating Instructions
Page 30 of 96
If due to strong gusts the rotor speed measured should exceed the rated speed by more than 15 %, an emergency shut-down will be carried out by means of the emergency pitch control units of the rotor blades. The LC display indicates main status 40 "rotor overspeed" with the corresponding sub-status stating which speed sensor was the first to record the excess speed. After 3 minutes the turbine will carry out a new starting attempt automatically.
If this fault signal has been indicated more than 5 times within the last 24 hours, a new starting attempt is not made. The status signal is flashing and first must be acknowledged.
In addition to the electronic monitoring, each of the three pitch control cabinets is equipped with three electromechanical switches which in case of excess rotor speed will shut down the turbine. These mechanical overspeed switches respond when the rated rotor speed is exceeded by more than 25 %. In that case, a quick blade adjustment is initiated via the emergency pitch control units of the rotor blades.
An automatic re-start of the turbine is then no longer possible. The mechanical overspeed switches have to be reset manually by service personnel and the fault must be acknowledged.
Main status: 40 :
41 :
48 :
Rotor overspeed
Rotor overspeed switch
Speed sensor error
3.11 Yaw control
The E-40 is provided with a combined wind sensor mounted on a supporting tube with integrated lighting protection system on the upper side of the nacelle. The combined wind sensor consists of a wind vane for the continuous measuring of the wind direction and an anemometer which measures the wind speed.
The yaw control system of the E-40 works at all wind speeds above 1.8 m/s.
Thus it is ensured that it is operating whenever a starting attempt is made (start-up wind speed: 2 m/s). Even if the turbine has already been shut down, e.g. due to high wind speed, it is still aligned in the direction of the wind. A re-alignment takes place when the average deviation of the nacelle direction compared to the wind direction measured is greater than the specified minimum angle (8° on a 1-minute average).
The yaw motion is monitored by counting the rotations of the yaw motor and by checking the yaw time for plausibility. During the re-positioning operation the rotational speed of the yaw drives is monitored by a sensor of the control and monitoring system. If the control system recognizes any irregularities in the yaw operation or the untwisting of cables (see chapter 3.12), a stopping process is initiated.
The nacelle of the E-40 is supported by two friction pads. Due to the yaw operations carried out, these pads wear out in the course of time (approx. 10 years). They are monitored by a sensor which responds when the pads are worn out to such an extent that they must be replaced. In that case the turbine is stopped slowly and yaw control is blocked by the control system.
Main status: 20 :
22 :
23 :
Wind measurement fault
Yaw control fault
Yaw pads worn
Operation
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