Abstract: An integrated transmission is effectively achieved within a series-excited motor by varying the number of winding turns in the field coil in relation to the speed-torque demand on the motor. At low motor speed, all of the field winding is engaged to produce the maximum available electromagnetic field, thereby increasing the motor's available torque and efficiency. When there is a high torque demand at high speed, only a portion of the field winding is engaged so that a reduced electromagnetic field is produced, thereby allowing a higher current in the motor, thereby allowing a higher torque to be produced. Thus the series motor with integrated transmission will have the same speed-torque characteristics as a system with a series motor and a conventional transmission. The integrated transmission can be implemented with relatively inexpensive relays and, if desired, by adding additional winding turns in the series field.

Abstract: In a series-wound motor with electric brake, which comprises an armature provided with an armature winding and at least two exciter coils mounted on pole shoes as well as switchgear which, in the operative phase of the motor, serially connect the exciter coils with the armature winding and connect the serial connection to terminal clamps for the operating voltage and which, in the braking phase, interrupt the connection to the terminal clamps and short-circuit the armature winding by the parallel connection of a winding, an independent optimization of the braking behavior is made possible in that at least one of the exciter coils is subdivided into two part windings and in that, when braking, one of the part windings has its polarity changed and is short-circuited with the armature winding.

Abstract: An improved driving circuit of a series or compound motor includes at least two series excitation field windings, one end of each of the series excitation windings being jointly connected, with the same polarity, to the armature, and at least one set of the series excitation field winding is isolated by means of diodes so as to receive power from different power sources.

Abstract: Optimal constructions for two motor/controller configurations are disclosed. The controller structure includes an H-bridge for controlling field current using synchronous-rectification of MOSFET devices, and a circuit for chopping the armature current using synchronous-rectification of MOSFET devices arranged in a half bridge. The controller may be configured with a series-wound or a separately excited DC traction motor. In the series-wound motor/controller configuration, the field and the armature current are separately controlled. In the separately excited motor/controller configuration, the field of the motor is preferably wound so that the rated field current is achieved at about 20% of the rated battery voltage. This provides a separately excited motor in which the field current can be boosted by a factor of 5 to achieve high start-up and low speed torques which match the torque outputs of a series-wound motor under similar operating conditions.