Personnel Safety and Access Issues

An integral part of wind-turbine design is the inclusion of the necessary safety provisions for operation and maintenance staff. Minimum requirements include the following:

• ladder access to the nacelle - this needs to be fitted with a fall-arrest device, unless ladder runs are short and protected by intermediate landings; careful attention needs to be paid to the route between the tower top and nacelle to avoid hazards arising from sudden yawing movements;

• an alternative means of egress from the nacelle, for use in case of fire in the tower - this can take the form of an inertia-reel device, enabling personnel to lower themselves through a hatch in the nacelle floor;

• locking devices for immobilizing the rotor and the yawing mechanism - rotor brakes and yaw brakes are not considered sufficient, because of the risk of accidental release and the occasional need to deactivate them for maintenance purposes; the rotor locking device should act on the low-speed shaft, so that its effectiveness is not dependent on the integrity of the gearbox - typically the device consists of a pin mounted in a fixed housing, which can be engaged in a hole in a shaft-mounted disc;

• guards to shield any rotating parts within the nacelle;

• suitable fixtures for the attachment of safety harnesses for personnel working outside the nacelle.

The designer needs to assess the requirement for all-weather access to the nacelle at an early stage. Lattice towers afford no protection from the weather when climbing, so the number of days on which access for maintenance is possible will be restricted. Similar restrictions will arise if the nacelle cover has to be opened to the elements in order to provide space for personnel to enter.

Consideration also needs to be given to the means of raising and lowering tools and spares. If the interior of the tower is interrupted by intermediate platforms, these operations have to be performed outside, with consequent weather limitations.

Standard rules for electrical safety apply to all electrical equipment. However, particular care must be taken with the routing of electrical cables between tower and nacelle, in order to avoid potential damage due to chafing when they twist. If the power transformer is located in the tower base or nacelle instead of in a separate enclosure at ground level, it should be partitioned off to minimize the fire risk to personnel.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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