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?
A :
B :
C :
D :
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
90 : How shunt field is connected to armature in DC shunt motor?
A : Series
B : Parallel
C : Series parallel
D : Combination
91 : Which is torque expression of DC series motor?
A :
B :
C :
D :
92 : What is the name of part marked as X?
A : Series field
B : Shunt field
C : Armature
D : Compensating winding
93 : Which motor is to be started with load?
A : 3 Phase induction motor
B : Slip ring induction motor
C : DC series motor
D : DC shunt motor
94 : Where the series motor is used?
A : Lathe
B : Hoist
C : Pumpset
D : Welding
95 : Which motor is used in heavy construction trucks?
A : Differential compound motor
B : Cumulative compound motor
C : DC shunt motor
D : DC series motor
96 : Which motor has both shunt field and series field winding?
A : Compound motor
B : Shunt motor
C : Series motor
D : Capacitor motor
97 : Which motor is used in steel rolling machinery?
A : DC Differential compound
B : DC cumulative compound motor
C : DC series motor
D : DC shunt motor
98 : Which protect DC motor from over load?
A : Commutator
B : Field diverter
C : Armature diverter
D : Starter
99 : How starting current is reduced in DC motors?
A : By using armature diverter
B : By using field diverter
C : By using starters
D : By controlling speed
100 : Which part of DC motor starter hold the handle in ON position?
A : OLR
B : No volt coil
C : Protective resistor
D : Spiral spring
101 : How the starting resistance is connected with armature of DC motor?
A : Parallel with armature
B : Series with armature
C : Series with field
D : Across with field
102 : Which starter is used for starting a DC compound motor?
A : Two point starter
B : DOL starter
C : Four point starter
D : Star-Delta starter
103 : What is the function of protective resistor in DC four point starter
A : To limit current in holding coil
B : To limit armature current
C : To limit field current
D : To limit the speed
104 : Which type of starter is used for DC series motor
A : DOL starter
B : Four point starter
C : Two point starter
D : Three point starter
105 : Which relation gives the speed of a DC motor?
A :
B :
C :
D :
106 : Which method of speed control of DC motor?
A : Supply voltage control
B : Field tapping
C : Field diverter
D : Armature diverter
107 : What is the part marked as X?
A : Diverter
B : Field coil
C : Starting resistor
D : Armature
108 : Which method of speed control used in DC shunt motor to control the speed below normal?
A : Field control
B : Armature control
C : Field tapping method
D : Field diverter method
109 : Which method of speed control used in DC motor to control the speed above normal
A : Field control
B : Armature control
C : Supply voltage control
D : Tapped field control
110 : Which method of speed control used for variation of speed from zero to above normal?
A : Supply voltage
B : Armature control
C : Shunt field control
D : Ward-Leanard system
111 : Which motor has this speed – torque characteristic?
A : DC series motor
B : DC shunt motor
C : Cumulative compound motor
D : Differential compound motor
112 : Which motor is used for traction purpose?
A : DC shunt motor
B : DC compound motor
C : DC series motor
D : Capacitor motor
113 : Which motor is used for grinders and polishers?
A : DC series motor
B : DC shunt motor
C : Differential compound motor
D : Cumulative compound motor
114 : Which instrument is used to measure insulation resistance of DC motor?
A : Earth tester
B : Megger
C : Voltmeter
D : Ammeter
115 : Which is the major reason for open circuit in armature circuit of DC machine?
A : Over voltage
B : Low voltage
C : Over load
D : Loose commulator segments
116 : Which test is conducted to determine the winding earth leakage of a DC motor?
A : Continuity test
B : Ground test
C : Short circuit test
D : Open circuit test
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