US Patent 11909283 Electric machine systems having magnetised bi-pole rotors

An electric machine system disclosed herein comprises first and second electric machines configured to drive a load. The first electric machine has a plurality of first rotors. The second electric machine has a plurality of second rotors. At least one of the second rotors is indexed relative to a respective one of the first rotors to, in use, provide a torque phase offset between the first and second electric machines. A shaft is coupled to the load and connects the respective one of the first rotors with the at least one of the second rotors. The respective one of the first rotors is coaxial with and axially spaced apart from the at least one of the second rotors.