A power conversion unit includes a power converter and a controller coupled to the secondary or output stage of the power converter. The vehicle additionally includes a vehicle controller that is configured to receive a programmable vehicle clip rate data input and monitor a groundspeed of the vehicle and a rotational speed of the cutting device as the vehicle moves across the ground surface. The drive system may be combined with other services including a transmission for incorporation in a vehicle. If the instruction is not associated with the speculative error, then the second checkpoint state may be updated based on the instruction. The present invention provides a magnetizer of a DC motor comprising: a case; a hemispherical permanent magnet provided within the case; a non-magnetic member provided below the hemispherical permanent magnet; and a coil provided to the non-magnetic member. 03 cubic inches and about 17 cubic inches, wherein substantially all of the pockets contain between about 0.