A rotor (14) for a rotating electrical machine is disclosed. The rotor (14) comprises a plurality of poles (24), each of the poles comprising a plurality of damper slots (30) for damper bars (32). The rotor is designed for use with a machine having a stator (12) with a plurality of stator slots (22) for accommodating stator windings (18). The damper slots (30) in the rotor have a damper slot pitch which is different from a stator slot pitch, and an arrangement which varies from one pole to another. This may lead to a reduction in higher harmonics.