Variable speed wind turbines have been used since 1970. And over the 30 year span, several variable wind speed technologies have come along and matured with the technological progress in the electronics industry. Wind turbines can be classified to their speed control (fixed/Variable RPM) and power control abilities such as stall control, pitch control, and active stall control (Jensen, 2007). Variable speed transmission is important because it allows the optimization of each section of the rotor to operate at its best lift to drag ratio. Varying the speed of the rotor along with pitch and yaw control form the basis of the control system of a wind turbine. The wind speed is not constant; therefore, a variable speed unit must be incorporate such that the rotor speed is a linear function of the wind speed. The use of variable speed wind turbines provides 20% more power than a fixed wind speed turbine. Current variable speed wind turbines vary the speed electrically, as opposed to mechanically. The most common electrical variable speed wind turbine is the doubly fed induction generator. The major obstacle with electrical variable speed transmissions lies in the power electronic conversion from AC to AC, which involves the conversion from AC-DC and then DCAC. This whole process results in an energy loss of 10%. The major concern with electrical variable transmission is the low reliability of the slip ring system. The use of a mechanically continuously variable transmission reduces torque spikes and increases component reliability. The Department of Energy, USA, concludes that the use of mechanical continuously variable transmissions to wind turbines provides an economic benefit of reducing the cost of energy by 11.2%. Based on the wind speed, the variable speed unit must control the rotor RPM and torque. Research done on traction and non-traction based continuously variable transmissions have resulted in the selection of the non-traction, positive engagement, pericyclic continuously variable