1) What is the primary (external) parameter that determines the speed of an unloaded d.c. motor?
2) What is the primary external factor that determines the steady state running current of a d.c.
motor, for any given armature voltage?
3) What determines the small current drawn by a d.c. motor when running without any applied
mechanical load?
4) What determines how much the speed of a d.c. motor reduces when the load on its shaft is
increased? Why does little motors slow down more than large ones?
5) What has to be done to reverse the direction of rotation of:
(a) a separately excited motor,
(b) a shunt motor,
(c) a series motor?
6) Most d.c. motors can produce much more than their continuously rated torque. Why is it
necessary to limit continuous torque?
7) What is the basic difference between a d.c. motor and a d.c. generator?
8) From the point of view of supply, an unloaded d.c. motor running light looks like a hig