Which type of motor is most suitable for computer printer device?

A $$4$$ pole dynamo with wave wound armature has $$51$$ slots containing $$20$$ conductors in each slot. The induced $$emf$$ is $$357$$ volts and the speed is $$5800$$ $$rpm$$. The flux per pole will be

A differentially compounded d.c. motor with interpoles and with brushes on the neutral axis is to be driven as a generator in the same direction with the same polarity of the terminal voltage. It will then

A cumulative compounded long shunt motor is driving a load at rated torque and rated speed. If the series field is shunted by a resistance equal to the resistance of the series field, keeping the torque constant.