© NOTES - Doc. Ing. Pavel Pivoňka, CSc. DC MOTORS ROTATING MACHINES - SAME CONSTRUCTION AS GENERATORS: MOTORIC RUN = 1 working status of DC machine SUPPLY = ELECTRIC SOURCE - electrical energy MOTOR - converts electrical DC into mechanical EVERY ROTATING MACHINE CAN WORK EITHER AS MOTOR OR GENERATOR

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. MOTOR ACTION

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. BASIC EQUATIONS OF DC MOTORS BEHAVIOR DEPENDS ON WINDINGS INTERCONNECTION SEPARATELY EXCITED (also permanent magnet) SERIES SHUNT

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. SEPARATELY EXCITED MOTOR (SEM) STEADY STATE EQUATIONS: !

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. SPEED CONTROL BY SEM constant power constant torque base speed

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. INFLUENCE OF R a ON n=f(T) CURVE base speed

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. TORQUE vs. SPEED BY SERIES MOTORS GENERATOR - only by braking advantage by start with load !

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. COMPARISON OF MOTORS

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. STARTING AND ROTATION REVERSAL SEPARATELY EXCITED AND SHUNT start: by U n is I s = 10 to 30 I n ----> variable U a or R a reversal:change polarity of U a or I f (only on not running machine - flux must not be zero !!!) SERIES start: variable U a - machine must not be unloaded !!! reversal:change polarity of U a or I f

© NOTES - Doc. Ing. Pavel Pivoňka, CSc. ENERGY BALANCE (POWER DIVISION) armature circuit 3 to 6%P in rotational losses 3 to 15%P in shunt field 1 to 5%P in MOTORGENERATOR