Pitch drive system

1. A pitch drive system for a wind turbine comprising a motor, a drive pinion operationally connected with the motor and a gear arranged to mesh with the drive pinion, wherein a first plate is provided on one side of the drive pinion, the first plate comprising one or more channels adapted to provide a lubricant to a tooth of the drive pinion that is in meshing engagement with teeth of the gear; and wherein the first plate is rotatably mounted with respect to the drive pinion.

2. The pitch drive system of claim 1 , wherein the channel is adapted to provide lubricant to at least one flank of the tooth of the drive pinion that is in meshing engagement with teeth of the gear.

3. The pitch drive system of claim 1 , wherein the first plate is a circular plate concentrically mounted on one side of the drive pinion, the circular plate having a radius that is substantially equal to or larger than that of the drive pinion.

4. The pitch drive system of claim 1 , wherein the channels are substantially T-shaped such that a lubricant flowing through a channel reaches both flanks of the tooth of the drive pinion.

5. The pitch drive system of claim 1 , further comprising a lubricant supply having an orifice, the orifice adapted to be in fluid communication with the channel of the first plate.

6. The pitch drive system of claim 5 , wherein the lubricant supply comprises a cylindrical piece arranged on a side of the first plate that is opposite to the drive pinion, the orifices being provided in the cylindrical piece.

7. The pitch drive system of claim 6 , wherein the cylindrical piece is rotatably arranged with respect to the first plate and comprises an orifice adapted to selectively be in fluid communication with each channel of the first plate.

8. The pitch drive system of claim 1 , wherein the lubricant is grease.

9. The pitch drive system of claim 8 , further comprising a second plate arranged on the other side of the drive pinion, opposite to the first plate, the second plate spanning at least the meshing engagement of the drive pinion with the gear such that a lubricant delivered by the channel can be retained by the second plate.

10. The pitch drive system of claim 9 , wherein the second plate comprises an outlet.

11. A wind turbine rotor comprising a hub, a plurality of blades, and one or more pitch drive systems according to claim 1 .

12. The wind turbine rotor of claim 11 , further comprising a valve and a control system for regulating the provision of lubricant to the channel.

13. A wind turbine comprising a wind turbine rotor according to claim 11 .

14. A wind turbine comprising a wind turbine rotor comprising a hub, a plurality of blades, and a pitch drive system, the pitch drive system further comprising:

a motor, a drive pinion operationally connected with the motor and a gear arranged to mesh with the drive pinion, wherein a first plate is provided on one side of the drive pinion, the first plate comprising one or more channels adapted to provide a lubricant to a tooth of the drive pinion that is in meshing engagement with teeth of the gear; and wherein the first plate is rotatably mounted with respect to the drive pinion.

15. The wind turbine of claim 14 , wherein the channels are substantially T-shaped such that a lubricant flowing through a channel reaches both flanks of the tooth of the drive pinion.

16. The wind turbine of claim 14 , wherein the lubricant is grease, further comprising a second plate arranged on the other side of the drive pinion, opposite to the first plate, the second plate spanning at least the meshing engagement of the drive pinion with the gear such that a lubricant delivered by the channel can be retained by the second plate.