Generators need dc to stimulate its magnetic field. The field current of DC is received from a different source known as an exciter. Either static or rotating type exciters are utilized for the system of AC power generation. Two types of exciters are there and they are Brushless Exciter and brush exciter. The basic difference between Brushless Exciter and brush exciter is the procedure utilized to transfer the current into the fields of generator. In respect of the generator static excitation is offered in various forms like voltage from a solid-state components system and voltage field-flash from batteries of storage type. Direct current generators are self-excited or excited separately. Systems of excitation in present mode include gear-connected or direct-connected shaft-driven direct current generators, separate prime mover or belt-driven or DC generators of motor-driven type and provided by means of static rectifiers. The exciter of brush-type may be mounted on the identical shaft like the armature of AC generator or may be stored separately from the generator.
The Wound Rotor Motors are excellent for high inertia load driving and under the circumstance it is needed that utmost torque is exerted at the minimum possible speed so as to enable the load rotating since the increase of speed in the torque needed is reduced and therefore the resistance is lowered and is removed fully at full speed. The making of Wound Rotor Motors varies in comparison to that of the motors of squirrel cage type since in place of the bars of rotor it includes 3 windings resembling to stator. These windings, being open, are attached to 3 slip rings built up over the rotor shaft. This circuit of rotor is attached to 3 brushes to an outside star attached variable resistance. The prime difficulty in respect of wound rotor motor is maintenance of its brushes and slip rings while squirrel cage motor does not need this. It has also the advantages of being able to drive loads of high inertia, controlling of speed through resistance and the facility of manageable start-up currents for maximum capacity utilization. These are some significant features of wound rotor motor.
The Wound Rotor Motors are excellent for high inertia load driving and under the circumstance it is needed that utmost torque is exerted at the minimum possible speed so as to enable the load rotating since the increase of speed in the torque needed is reduced and therefore the resistance is lowered and is removed fully at full speed. The making of Wound Rotor Motors varies in comparison to that of the motors of squirrel cage type since in place of the bars of rotor it includes 3 windings resembling to stator. These windings, being open, are attached to 3 slip rings built up over the rotor shaft. This circuit of rotor is attached to 3 brushes to an outside star attached variable resistance. The prime difficulty in respect of wound rotor motor is maintenance of its brushes and slip rings while squirrel cage motor does not need this. It has also the advantages of being able to drive loads of high inertia, controlling of speed through resistance and the facility of manageable start-up currents for maximum capacity utilization. These are some significant features of wound rotor motor.
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