7 rotating dc machines - montana
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Sarah LukesEELE 250/Fall 2011 Montana State University
Basic principles of rotating dc machines are the same as those of the linear dc machine
A rotating dc machine can be modeled by an equivalent circuit
Magnetization curve
Sarah LukesEELE 250/Fall 2011 Montana State University 2
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Sarah LukesEELE 250/Fall 2011 Montana State University 3
Sarah LukesEELE 250/Fall 2011 Montana State University 4
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Sarah LukesEELE 250/Fall 2011 Montana State University 5
Sarah LukesEELE 250/Fall 2011 Montana State University 6
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Sarah LukesEELE 250/Fall 2011 Montana State University 7
Only a few conductors commutated (switched) at a time, so voltage fluctuations are less pronounced.
Field Circuit
Sarah LukesEELE 250/Fall 2011 Montana State University 8
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Resistance of armature windings and brush
Induced armature voltageor back EMF:
Torque:
Does not include losses
Sarah LukesEELE 250/Fall 2011 Montana State University 9
Developed power:
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A rotating dc machine can be modeled by an equivalent circuitequivalent circuit
Magnetization curve provides relationship between the armature voltage EA and the field current IF
Sarah LukesEELE 250/Fall 2011 Montana State University 11