Wireman 2nd year mcq
Wireman – Semester 3 Module 3 – DC Generator
34 : What is the working principle of DC generator?
A : Amperes law
B : Faradays law of electro magnetic induction
C : Faradays law of electrolysis
D : Lenzs law
35 : What type of Emf is induced in DC generator?
A : Dynamically induced
B : Statically induced
C : Self induced
D : Mutually induced
36 : What rule is used to find the direction of induced emf in DC generator?
A : End rule
B : Flemings right hand rule
C : Cork screw rule
D : Flemings left hand rule
37 : Which generator the field winding is connected across the armature?
A : Series generator
B : Pulse generator
C : Magneto generator
D : Shunt generator
38 : Which type of DC generator can be called as a constant voltage generator?
A : Series generator
B : Shunt generator
C : Differential compound generator
D : Under compound generator
39 : Which part of a DC generator is laminated?
A : Winding
B : Shaft
C : Armature core
D : Yoke
40 : Which material is used for commutator segment?
A : Copper
B : Hard-drawn copper
C : Carbon
D : Brass
41 : Identify the part marked as X in figure?
A : Teeth
B : Slot
C : Key way
D : Air duct
42 : What is the function of commutator in DCgenerator?
A : To convert AC to DC
B : To convert DC to AC
C : To rotate the armature
D : To collect current
43 : Where the brushes are housed in DC generator?
A : Yoke
B : Terminal box
C : Shaft
D : Brush holder
44 : Which part of the DC generator helps tospread out field flux in the air gap?
A : Pole shoes
B : Yoke
C : Armature
D : Commutator
45 : What is indicated by letter N in this formula?
A : Number of conductor
B : Speed in rpm
C : Number of parallel path
D : Number of poles
46 : Which is the formula of emf equation in wave wound DC generator?
47 : What will happen, if shunt field resistance is too large?
A : Fails to build up voltage
B : Build up voltage
C : Generator doesnt run
D : Voltage increases
48 : Which determines the polarity of induced emf in DC shunt generator?
A : Number of conductor
B : Number of parallel path
C : Direction of rotation of armature
D : Number of field poles
49 : Which type of DC generator is used as booster generator?
A : Series generator
B : Separately exited generator
C : Shunt generator
D : Compound generator
50 : Which type of compound generator is illustrated?
A : Short shunt compound generator
B : Long shunt compound generator
C : Differential compound generator
D : Separately excited generator
51 : Which generator has both shunt and series field winding?
A : Compound generator
B : Shunt generator
C : Series generator
D : Separately excited generator
52 : What is the name of DC generator?
A : Short shunt compound generator
B : Long shunt compound generator
C : Differential compound generator
D : Shunt generator
53 : Which generator, shunt field flux is opposed by series field flux?
A : Differential compound generator
B : Cumulative compound generator
C : Shunt generator
D : Series generator
54 : Which DC compound generator the shunt field is connected in parallel to armature only?
A : Shunt generator
B : Short shunt generator
C : Series generator
D : Long shunt generator
55 : What is the function of series field winding in cumulative compound generator?
A : To oppose the shunt field
B : To oppose main field
C : To assist the shunt field
D : To oppose armature
56 : What is the full form of TPT?
A : Trailing Pole Tip
B : Temporary Pole Tip
C : Topmost Pole Tip
D : Temporary Present Tip
57 : What is the full form of GNA?
A : General Neutral Axis
B : Geometrical Neutral Axis
C : Geographical Neutral Axis
D : Geometrical Numerical Axis
58 : How the effect of cross magerising effect is nullified?
A : By changing commutator
B : By reversing direction
C : By shifting the brush position
D : By changing armature
59 : What is the function of compensating winding in DC machine?
A : Reduce armature reaction
B : To produce flux
C : To reduce humming
D : To reduce friction
60 : What is the function of interpole in DC machine?
A : To reduce humming
B : To improve commutation
C : To reduce magnetic locking
D : To reduce vibration
61 : What is the name of part marked as X?
A : Main pole
B : Interpole
C : Compensating winding
D : Pole shoe
62 : What is the full form of MNA?
A : Micro Neutral Axis
B : Minimum Neutral Axis
C : Miniature Neutral Axis
D : Magnetic Neutral Axis
63 : How the compensating winding is connected with the armature of DC machine?
A : Series
B : Parallel
C : Series – Parallel
D : Between armature and field
64 : How the inter poles are connected to the armature of a DC machine
A : Parallel
B : Series
C : Series – Parallel
D : Between armature and field
65 : What is the effect of rough commutation in DC generators?
A : Heavy sparking in the brushes
B : Terminal voltage reduces to zero
C : Voltage drop at brushes increases
D : Terminal voltage reduces considerably
66 : Which generator has very high value of voltage regulation?
A : Shunt generator
B : Compound generator
C : Series generator
D : Magneto generator
67 : Which of the following is the voltage equation for DC series generator?
68 : Which type of DC generator is used for welding purpose?
A : Differential compound generator
B : Cumulative compound generator
C : Shunt generator
D : Series generator
69 : Which type of DC generator is used for
centrifugal pump?
A : Series generator
B : Shunt generator
C : Differential compound generator
D : Under compound generator
70 : Which type of DC compound generator is used for light and power load?
A : Flat compound
B : Under compound
C : Differential compound
D : Differential long shunt generator
71 : Which of the following generator does not build up voltage if load is not connected?
A : Series generator
B : Shunt generator
C : Long shunt compound generator
D : Short shunt compound generator
72 : What is the condition of voltage while operating DC generators in parallel?
A : Must be more
B : Above 250V
C : Must be the same
D : Must be less
73 : Where the positive terminal of the generator is connected while parallel operation?
A : -ve bus bar
B : Neutral point
C : +ve bus bar
D : Phase wire
74 : How load is shifted from one generator to other when DC generators are operating in parallel?
A : Adjusting speed
B : Adjusting armature resistance
C : By stopping the generator
D : Adjusting excitation
75 : Which of the following is the necessity of parallel operation of DC generators?
A : Continuity of supply
B : Reduce cost
C : Easy operation
D : Easy connection
76 : What is the cause for the fault, that brush makes chattering noise?
A : Over loading
B : Insufficient brush tension
C : Excessive brush pressure
D : Insufficient brush spring pressure
77 : What is the cause for the fault that bearing over heating in DC generator?
A : Unbalanced armature
B : Foreign material in air gap
C : More current in armature
D : Incorrect grade of bearing grease
78 : What is the cause for the fault that heavy sparking in light loads in DC generator?
A : Oily commutator surface
B : Defective alignment
C : Defective bearing
D : Wrong alignment
79 : Which machine converts electrical power to mechanical power?
A : Alternator
B : DC motor
C : DC generator
D : Transformer
80 : Which rule is used to find out direction of rotation of DC motor?
A : Flemings left hand rule
B : Flemings right hand rule
C : Cork screw rule
D : End rule
81 : Which type of magnetic field is necessary for working of DC motor?
A : Pulsating magnetic field
B : Alternating magnetic field
C : Rotating magnetic field
D : Uniform magnetic field
82 : What is the value of angle between fingers in Flemings left hand rule?
A : Right angles to each other
B : 40 degrees to each other
C : 45 degrees to each other
D : 60 degrees to each other
83 : Which formula is used to find out back emf in DC motor?
84 : What is the unit of torque in DC motor?
A : Joule
B : Newton
C : Newton – metre
D : Watt
85 : Which represent the turning or twisting moment of force in an axis?
A : Centrifugal force
B : Speed
C : Twisting
D : Torque
86 : Which motor has very high starting torque?
A : DC series motor
B : DC shunt motor
C : DC differential compound motor
D : DC cumulative compound motor
87 : What is the name of DC motor?
A : Short shunt compound motor
B : DC Series motor
C : DC Shunt motor
D : Long shunt compound motor
88 : What are the field winding terminals of a DC shunt motor?
A : E1 and E2
B : A1 and A2
C : D1 and D2
D : F1 and F2
89 : Which type of motor considered as constant speed motor?
A : DC shunt motor
B : DC series motor
C : AC series motor
D : Universal motor
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