Centrifugal fan with back blades

A centrifugal fan for cooling an electrical machine, the centrifugal fan being configured to rotate around a rotating axis, the centrifugal fan comprising:

• a first plate comprising an air inlet configured to face a rotor of the electrical machine to receive air;
• a second plate spaced apart from the first plate in a direction parallel to the rotating axis;
• a plurality of first blades arranged between the first plate and the second plate;
• and
• a plurality of second blades arranged on a side of the second plate away from the first plate and configured to reduce an air pressure in vicinity of the second plate;
• wherein each of the plurality of first blades has a first arc shape and each of the plurality of the second blades has a second arc shape, and wherein a curvature of the first arc shape is the same as a curvature of the second arc shape.