Study and operation of the DC speed and position control setup 
1. A 230 V dc shunt machine has armature circuit resistance (including brushes) of 0.5 Ω and field circuit resistance of 115 Ω. If this machine is connected to 230 V supply mains, find the ratio of speed as a generator to the speed as a motor. The line current in each case is 40 A.
2. If a resistance is added in series with the field winding of dc shunt motor, then its ____
3. The torque developed on a dc motor shaft is directly proportional to _______
4. An important type of dc motor in which the commutation is done electronically is called _______
5. If the applied voltage to a dc motor is 220 V, then the back emf for maximum power developped is,
6. A dc motor has 0.5 Ω resistance between its terminals. It runs at 730 rpm while taking 20 A from 300 V supply. Assume there is no saturation, what is the speed it will run when taking only 10 A from same supply
7. A 200 V dc generator supplies 4 kw at a terminal voltage of 200 V, the armature resistance being 0.5 Ω. If the machine is operated as a motor at the same terminal voltage with the same terminal current, find the ratio of the generator speed Ng to the motor speed Nm.
8. A 50 kw dc shunt motor is loaded to draw rated armature current at any given speed. When driven at 1.5 times the rated speed by field control, the output power delivered by the motor is approximately
9. A dc shunt motor runs at 750 rpm from 250 V supply and is taking a full-load line current of 60 amperes. Its armature and field resistances are 0.4 Ω and 125 Ω respectively. Assuming 2 V brush drop and negligible armature reaction effect, calculate the no-load speed for a no-load line current of 6 amperes
10. In which method of speed control, the dc motor acts as constant torque, variable power drive?