Electric Machine with Permanent Magnetic Rotor

An electric motor (10) comprises a stator (20) having a primary winding and a rotor (130a,b) arranged to rotate in the stator (20). The rotor comprises a shaft (160), a first magnetic rotor component (140) and a second magnetic rotor component (150), each magnetic rotor component (140,150) having a magnetic pole of a first polarity (43,43',53,53') and a magnetic pole of a second polarity (47,47',57,57'). At least one of the first and second rotor components (140,150) further comprises a structure (35) for carrying induced eddy currents. The second magnetic rotor component (150) is rotatable with respect to the first magnetic rotor component (140) around the shaft (160) from a low-flux orientation to a high-flux orientation. The motor (10) is arranged such that the second magnetic rotor component (150) is in the low-flux orientation when the rotor (130a,b) is at rest and is in the high-flux orientation when the rotor (130a,b) is rotating at an operating speed.