A 240-V, 900-rpm, dc series motor takes 25 A at full load. The armature and field-winding resistances are Ra=0.2 ohm and

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A 240-V, 900-rpm, dc series motor takes 25 A at full load. The
armature and field-winding resistances are Ra=0.2 ohm and Rs = 0.3
ohm, respectively. The rotational loss is 300 W. Calculate:

a) The back emf
b) The power output
c) The output torque
d) The copper loss
e) The efficiency
f) If the motor is driving a load with a torque 46 N.m at a
speed of 800 rpm, what is the motor current?
d) calculate the efficiency
e) If a pulley of diameter 20 cm is wrap around the rim of the
motore, what is the force exerted by the motor?