Study and operation of the DC speed and position control setup 
1. Mark the wrong option. Which of the following cause and effect behaviour in speed control is correct when field resistance is increased.
2. Small dc motors have best speed control by _________
3. Consider the following statements regarding speed control of dc motor.
1) Field control method is used to vary the speed of the motor above the rated speed.
2) Armature resistance control method is used to vary speed both below and above the rated speed.
which one is correct?
1) Field control method is used to vary the speed of the motor above the rated speed.
2) Armature resistance control method is used to vary speed both below and above the rated speed.
which one is correct?
4. In armature voltage control method or rheostatic control method for speed control in dc shunt motor, a variable resistance is ____
5. The most economical method of electrical braking is
6. The torque constant (Km), of a permanent magnet dc motor is 0.25 V sec/radian and armature resistance is 2 Ω. If the applied armature voltage is 90 V, then its zero speed torque is
7. For a dc shunt motor if exitation is changed, then ____
8. What will happen if the back emf of a dc motor vanishes suddenly?
9. A 250 V dc series motor has armature and series-field resistances of 0.25 Ω and 0.15 Ω respectively. Calculate the current for developing a torque of 80 Nm at 1200 rpm.
10. With the increase in temperature, the speed of series and shunt motor will ______, ______ respectively.