Q31. A separately excited DC motor runs at 1500 rpm under no-load with 200 V applied to the armature. The field voltage is maintained as its related value. The speed of the motor, when it delivers a torque of 5 N-m, is 1400 rpm as shown in figure. The rotational losses and armature reaction are neglected. For the motor to deliver a torque of 2.5 N-m at 1400 rpm, the armature voltage to be applied is

Q32. The critical resistance of a DC machine refers to which of the following component!?

Q33. A DC shunt generator has an induced voltage of 220 V on open circuit. When the machine is on load the terminal voltage is 200 V. Find the load current if the field resistance is 100 \(\Omega\) and armature resistance is 0.2 \(\Omega\).

Q34. A 240 V d.c. series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 ohm. What resistance must be added to obtain the rated torque at starting?

Q35. Two DC series motors connected in series draw current I from supply and run at speed N. When the same two motors are connected in parallel taking current I from the supply, the speed of each motor will be

Q36. A long shunt DC compound generator delivers 110 KW at 220 volts. If \(R_a = 0.01\) ohms, \(R_{se} = 0.002\) ohms and shunt field resistance is of 110 ohms, calculate the value of induced EMF. (consider up to one decimal place)

Q37. Armature reaction in DC motor is increased \(_{-----------}\)

Q38. In lap winding, the number of brushes is equal to

Q39. A 4 pole, lap-wound DC shunt generator has an armature winding consisting of 220 turns each of 0.004 Ω. The armature resistance is

Q40. An eight-pole wave-connected armature has 600 conductors and is driven at 625 rev/min. If the flux per pole is 20 mWb, determine the generated emf.