Yaw drive

The yaw drive is an important component of the horizontal axis wind turbines' yaw system. To ensure the wind turbine is producing the maximal amount of electric energy at all times, the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. This only applies for wind turbines with a horizontal axis rotor. The wind turbine is said to have a yaw error if the rotor is not aligned to the wind. A yaw error implies that a lower share of the energy in the wind will be running through the rotor area. (The generated energy will be proportional the cosine of the yaw error).

History

When the windmills of the 18th century included the feature of rotor orientation via the rotation of the nacelle, an actuation mechanism able to provide that turning moment was necessary. Initially the windmills used ropes or chains extending from the nacelle to the ground in order to allow the rotation of the nacelle by means of human or animal power.

Another historical innovation was the fantail. This device was actually an auxiliary rotor equipped with plurality of blades and located downwind of the main rotor, behind the nacelle in a 90° (approximately) orientation to the main rotor sweep plane. In the event of change in wind direction the fantail would rotate thus transmitting its mechanical power through a gearbox (and via a gear-rim-to-pinion mesh) to the tower of the windmill. The effect of the aforementioned transmission was the rotation of the nacelle towards the direction of the wind, where the fantail would not face the wind thus stop turning (i.e. the nacelle would stop to its new position).

Yaw

Yaw may refer to:

Yam (god)

Yam, Yamm, or Yammu was a Levantine sea and river god, popular in the Bronze and Early Iron Ages.

Yam, from the Canaanite word Yam (Hebrew: ים‎) meaning "Sea", also written Yaw, is one name of the Ugaritic god of Rivers and Sea. Also titled Judge Nahar ("Judge River"), he is also one of the 'ilhm (Elohim) or sons of El, the name given to the Levantine pantheon. Others dispute the existence of the alternative names, claiming it is a mistranslation of a damaged tablet. Despite linguistic overlap, theologically this god is not a part of the later subregional monotheistic theology, but rather is part of a broader and archaic Levantine polytheism.

Yam is the deity of the primordial chaos and represents the power of the sea, untamed and raging; he is seen as ruling storms and the disasters they wreak. The gods cast out Yam from the heavenly mountain Sappan (modern Jebel Aqra; Sappan is cognate to Tsephon). The seven-headed dragon Lotan is associated closely with him and he is often described as the serpent. He is the Canaanite equivalent of the Sumerian Tiamat, the primordial mother goddess.

Drive (Béla Fleck album)

Drive is an album by American banjoist Béla Fleck. The album was produced toward the end of Fleck's New Grass Revival career and before the Flecktones were formed and included an all-star list of bluegrass performers.

Track listing

All tracks written by Béla Fleck

Bonus track on the SACD version*

Personnel

References

Glossary of baseball (D)

D

daisy cutter

dance

dark one

dead arm

dead ball

Dead Ball Era

dead pull hitter

dead red

deal

decided in the last at bat

deep in the count

defensive efficiency rating

defensive indifference

deliver

designated hitter

deuce

deuces wild

Melanie Blatt

Melanie Blatt (born 25 March 1975) is an English singer-songwriter and actress. She is also the daughter of author and travel expert David Blatt. She rose to fame in 1997 as a member of the BRIT Award-winning girl group All Saints. The group have gained five number one singles, two multi-platinum albums, two BRIT Awards and have sold over 10 million records worldwide making them one of the best-selling girl groups of all time, and the second best-selling girl group in the UK. Melanie Blatt began recording a solo album in 2003, working with numerous producers including Xenomania and released her debut solo single "Do Me Wrong" in 2003. Blatt was later dropped by her record label, and her solo album was cancelled. In 2005, she made a return to music with her single "See Me", and began recording another album independently which was later shelved and cancelled in favour of the All Saints reunion. Starting in 2013, she was a judge on the television series The X Factor NZ.

Early life