TESTING OF D.C. MACHINES
Objective Questions Short notes Objective questions (Answers are given below)
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D.C. MOTOR
Objective Questions Short notes Objective questions (Answers are given below) In a d.c. motor, undirectional torque is producedwith the help of(a) brushes (b) commutator(c) end-plates (d) both (a) and (b) The counter e.m.f. of a d.c. motor(a) often exceeds the supply voltage(b) aids the applied voltage(c) helps in energy conversion(d) regulates its armature voltage The … Read more
SEMICONDUCTOR PHYSICS
Objective Questions Short notes Objective questions (Answers are given below) The total energy of a revolving electron in anatom can(a) have any value above zero(b) never be positive(c) never be negative(d) not be calculated. An atom is said to be ionised when any one ofits orbiting electron(a) Jumps from one orbit to another(b) is raised … Read more
SINGLE-PHASE MOTORS
Objective Questions Short notes Objective questions (Answers are given below) The starting winding of a single-phase motoris placed in the(a) rotor (b) stator(c) armature (d) field. One of the characteristics of a single- phasemotor is that it(a) is self-starting(b) is not self-starting(c) requires only one winding(d) can rotate in one direction only. After the starting … Read more
TRANSFORMER: THREE PHASE
Objective Questions Short notes Objective questions (Answers are given below) Which of the following connections is best suitedfor 3-phase, 4-wire service ?(a) Δ − Δ (b) Y − Y(c) Δ − Y (d) Y − Δ In a three-phase Y-Y transformer connection,neutral is fundamental to the(a) suppression of harmonics(b) passage of unbalanced currents due tounbalanced … Read more