The direct-drive wind turbine developed by Xiangtan Electric Machine Factory is in the leading position in the world. (1) Direct-driven wind turbines convert wind energy into electric energy.

(1) When the direct-drive wind turbine works, the rotor (permanent magnet) of the generator is mainly driven by the wind to move in the stator coil, so that the conductor in the stator coil is equivalent to cutting the magnetic induction line, and then a current is generated in the stator coil. In this process, the mechanical energy of wind is converted into electrical energy.

(2) Wind energy can be continuously supplemented from nature and is a renewable energy source;

If the wind energy in one day is about 1.8× 10 16J, the amount required for complete combustion of coal is:

m = Qq = 1.8× 10 16j 3× 107j/kg = 6× 108kg = 6× 105t。

So the answer is: (1) machinery, current; (2) Renewable, equivalent to 6× 105 tons of coal.