A method of cooling a control drive of a fan assembly, the fan assembly comprising a fan casing having an inlet and an outlet, a fan rotor mounted inside the fan casing and configured to create an air flow from the inlet to the outlet, an electric motor connected to the fan rotor and configured to drive the fan rotor, and a control drive configured to control the electric motor, the method comprising:
- positioning the control drive on an external side of the fan casing in a region corresponding to an opening on the fan casing on a low pressure side of the fan;
- and allowing an external ambient air to enter the fan casing through the opening and pass over the control drive, thereby cooling the control drive.