Alternator excitation system

An excitation system for a brushless alternator driven by a source of motive power, comprising:

• a main generator coupled to and supplying power to a load, the main generator having an armature coil, a field coil for establishing a main generator magnetic field in space occupied by the main generator armature coil and means for coupling the main generator to the source of motive power such that the armature coil and the main generator magnetic field move relative to one another to develop main generator output power in the armature coil;
• an exciter having an exciter field coil connected in series between the main generator armature coil and the load so that the exciter field coil carries the main generator AC output current to establish an alternating exciter magnetic field, an exciter armature coil within the exciter magnetic field, the coupling means also coupling the exciter to the source of motive power such that the exciter magnetic field and the exciter armature coil move relative to one another to develop an exciter output current in the exciter armature coil;
• and
• means for connecting the exciter output current to the main generator field coil to establish the main generator magnetic field.

An excitation system for a brushless alternator driven by a source of motive power, comprising:

• a main generator coupled to and supplying power to a load having a number of armature coils, a field coil for establishing a main generator magnetic field in space occupied by the main generator armature coils and means for coupling the main generator to the source of motive power such that the armature coils and the main generator magnetic field move relative to one another to develop polyphase AC output power in the armature coils;
• an exciter having a number of exciter field coils connected in series between the number of main generator armature coils and the load so that the exciter field coils receive the polyphase AC output power to establish an exciter magnetic field, the exciter also having an exciter armature coil within the exciter magnetic field, the coupling means also coupling the exciter to the source of motive power such that the exciter magnetic field and the exciter armature coil move relative to one another to develop an exciter output current in the exciter armature coils;
• and
• means for connecting the exciter output current to the main generator field coil to establish the main generator magnetic field.

An excitation system for a brushless alternator driven by a source of motive power, comprising:

• a main generator for developing output currents having field and armature coils, one of the field and armature coils being driven by the source of motive power such that the field and armature coils move relative to one another;
• an exciter having first and second sets of field windings and first and second sets of armature windings;
• a source of direct current coupled to the first set of field windings for establishing a first exciter magnetic field in the space occupied by the first set of armature windings;
• means for coupling the second set of field windings to the output currents from the main generator armature coils to establish a second exciter magnetic field in the space occupied by the second set of armature windings;
• means for coupling the exciter to the source of motive power to move both sets of exciter armature windings and the exciter magnetic fields relative to one another to develop first and second exciter armature currents in the first and second armature windings, respectively;
• means for combining the first and second exciter armature currents;
• and
• means for coupling the combined first and second exciter armature currents to the main generator field coil.

An excitation system for a brushless alternator for energizing a load and driven by a source of motive power, comprising:

• a main generator having a rotor, a stator, a set of armature coils on the stator, a field coil for establishing a main generator magnetic field in a space occupied by the set of main generator armature coils and means for coupling the main generator rotor to the source of motive power such that the main generator magnetic field moves relative to the set of armature coils to develop main generator polyphase AC output currents in the set of armature coils;
• a source of direct current;
• an exciter having a first set of exciter field windings coupled to the source of direct current to establish a first exciter magnetic field, a second set of exciter field windings coupled in series between the main generator armature coils and the load to establish a second exciter magnetic field, a first set of exciter armature coils within the first exciter magnetic field, a second set of exciter armature coils within the second exciter magnetic field, the coupling means also coupling the exciter to the source of motive power such that the first and second sets of exciter armature coils move relative to the first and second exciter magnetic fields to develop first and second exciter armature currents in the first and second exciter armature coils, respectively;
• means for combining the first and second exciter armature currents to develop a combined exciter armature current;
• means for rectifying the combined exciter output current;
• and
• means for connecting the rectified combined exciter output current to the main generator field coil to establish the main generator magnetic field.