DC GENERATOR THEORY
DC Generators
Summary
DC generator theory is summarized below.
DC Generator Theory Summary
The three conditions necessary to induce a voltage into a conductor are:
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Magnetic field
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Conductor
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Relative motion between the two
The left-hand rule states that if you point the index finger of the left hand in the
direction of the magnetic field and point the thumb in the direction of motion of
the conductor, the middle finger will point in the direction of current flow.
The terminal voltage of a DC generator is adjusted by varying the field strength.
The voltage rating of a DC generator is based on the insulation type and design
of the machine.
The current rating of a DC generator is based on the size of the conductor and
the amount of heat that can be dissipated in the generator.
The power rating of a DC generator is based on the mechanical limitation of the
device that is used to turn the generator.
The upper speed rating of a DC generator is determined by the speed at which
mechanical damage is done to the machine. The lower speed rating is based on
the limit for field current.
There are four internal losses that contribute to lower efficiency of a DC
generator.
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Copper losses
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Eddy-current losses
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Hysteresis losses
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Mechanical losses
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