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Dc motors
| 1-Dont try to cram or spend more time here just read it fast and cover syllabus then practice MCQ's cheptor of same topic to check your progress. . |
| 2-Wrong options are also given but dont concentrate there, Right answer is in bold format. |
| Q1 ⇒ Which D.C. motor has got maximum
self loading property? Differentially compotinded motor [other wrong options] [Discuss in forum] |
| Q2 ⇒ When the speed of a D.C. motor increases back e.m.f. increases and current drawn decreases [other wrong options] [Discuss in forum] |
| Q3 ⇒ Which D.C. motor is generally preferred
for cranes and hoists ? Series motor [other wrong options] [Discuss in forum] |
| Q4 ⇒ As the load is increased the speed of
D.C. shunt motor will reduce slightly [other wrong options] [Discuss in forum] |
| Q5 ⇒ If Ia be the armature current, then
speed of a D.C. shunt motor is independent of la [other wrong options] [Discuss in forum] |
| Q6 ⇒ If a D.C. motor designed for 40°C ambient
temperature is to be used for 50°C
ambient temperature, then the motor is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor [other wrong options] [Discuss in forum] |
| Q7 ⇒ Ward-Leonard control is basically a voltage control method [other wrong options] [Discuss in forum] |
| Q8 ⇒ The hysteresis loss in a D.C. machine
least depends on Rate of flow of ventilating air [other wrong options] [Discuss in forum] |
| Q9 ⇒ The retardation test is applicable to
shunt motors and generators and is
used to find the stray losses [other wrong options] [Discuss in forum] |
| Q10 ⇒ Which of the following steps is likely to
result in reduction of hysteresis loss in
a D.C. generator ? Using material of low hysteresis coefficient for armature core material [other wrong options] [Discuss in forum] |
| Q11 ⇒ D.C. generators are installed near the
load centres to reduce line losses [other wrong options] [Discuss in forum] |
| Q12 ⇒ When the armature of a D.C. motor
rotates, e.m.f. induced is back e.m.f. [other wrong options] [Discuss in forum] |
| Q13 ⇒ The speed of a D.C. shunt motor is
required to be more than full load
speed. This is possible by reducing the field current [other wrong options] [Discuss in forum] |
| Q14 ⇒ A series motor is started without load.
The effect is that the speed increases rapidly [other wrong options] [Discuss in forum] |
| Q15 ⇒ In a D.C. motor, unidirectional torque
is produced with the help of both (b) and (c) [other wrong options] [Discuss in forum] |
| Q16 ⇒ The operation of electric generators
and motors depend on the interaction
between magnetic field and electric current [other wrong options] [Discuss in forum] |
| Q17 ⇒ Which of the following statements is
correct, in case of a D.C. series motor ? It should be directly connected to the load [other wrong options] [Discuss in forum] |
| Q18 ⇒ Which of the following is not necessarily
the advantage of D.C. motors over
A.C. motors ? Low cost [other wrong options] [Discuss in forum] |
| Q19 ⇒ A D.C. motor can be easily identified by commutator [other wrong options] [Discuss in forum] |
| Q20 ⇒ Speed control of a cumulatively compounded
D.C. motor can be effected
through change of any of the above [other wrong options] [Discuss in forum] |
| Or |