Module-6 AC Generator (2nd)

 

133 : Which working principle AC generator?

A : Faradays laws of electro magnetic induction
B : Ohms law
C : Lenzs law
D : Faradays laws of electrolysis

134 : Which Emf is induced in a AC generator?
A : Dynamically induced emf
B : Statically induced emf
C : Counter emf
D : Self induced emf

135 : Which part rotates in large alternator?
A : Field
B : Armature
C : Brush
D : Yoke

136 : Which material is used to construct armature core of alternator?
A : Spring steel
B : Mild steel
C : Silicon steel
D : Forged steel

137 : Which rotor is used in high speed alternator?
A : Smooth cylindrical
B : Salient pole
C : Projected pole
D : Squirrel cage rotor

138 : Which type of slots are used in armature core of alternator?
A : Totally closed
B : Wide open
C : Semi closed
D : Semi open

139 : What are the terminal markings of a 3 phase star connected alternator?
A : U, V, W and N
B : A, B, C and N
C : 1, 2, 3 and 4
D : X, Y, Z, N

140 : What is the phase displacement between three windings in an alternator?
A : 120°
B : 90°
C : 360°
D : 180°

141 : Which type of rotor has small diameter and large axial length?
A : Smooth cylindrical
B : Salient pole
C : Projecting pole
D : Squirrel cage

142 : What is the excitation source of a large alternator?
A : DC shunt generator
B : Rectifier
C : DC series generator
D : Battery

143 : Which type of alternator is used for high speed operation?
A : Salient pole alternator
B : Smooth cylindrical pure alternator
C : Projected pole alternator
D : Impulse turbo alternator

144 : How the alternators are rated?
A : KVA
B : KW
C : KVAR
D : KWH

145 : What is the Emf equation of an ideal alternator?
A :
B :
C :
D :

146 : What is the formula for calculating total load on 3-phase alternator?
A :
B :
C :
D :

147 : What is the formula for voltage regulation of an alternator?
A :
B :
C :
D :

148 : What is the condition for voltage in parallel operation of 3-phase alternator?
A : Must be same
B : Must be different
C : Must be low
D : Must be high

149 : Which is the condition for parallel operation of 3-phase alternator?
A : Frequency must be same
B : Voltage must be different
C : Sequence must be different
D : Polarity must be different

150 : Why parallel operation of alternators is necessary?
A : To get more voltage
B : To share more loads
C : To improve efficiency
D : To maintain constant frequency

151 : Which method of synchronising is given?
A : Dark lamp method
B : Bright lamp method
C : Synchroscope method
D : Two bright one dark method

152 : What method is used for parallel operation of alternator?
A : Dark and bright lamp method
B : Ward – leonald method
C : Over excitation method
D : Under excitation method

153 : Which is the correct time of parallel operation of alternators in lamp method illustrated?
A : All 3 lamps in dark
B : All 3 lamps in bright
C : Two lamps bright and one lamp dark
D : One lamp bright and two lamps dark

154 : How the 3 lamps glow under parallel operation of alternators in bright lamp method?
A : All 3 lamps in dark
B : All 3 lamps in bright
C : Two lamps bright and one lamp dark
D : One lamp bright and two lamps dark

155 : How many lamps are required for parallel operation of two 3 phase alternators?
A : 3
B : 6
C : 8
D : 10

156 : What is the name of the instrument used to indicate the correct time for parallel operation of alternators?
A : Megger
B : Phase sequence meter
C : Synchroscope
D : Centre zero ammeter

157 : Which is the exact instant of parallel operation of alternators in Weston synchroscope illustrated?
A : Indicating the fast direction
B : Indicating the slow direction
C : Visible at its central position
D : Oscillating in between fast and slow

158 : Which instrument is the special form of power factor method?
A : Synchroscope
B : Frequency meter
C : Wattmeter
D : Phase sequence meter

159 : Which is used in Weston type electro dynamo meter synchroscope?
A : Iron vane
B : Fixed coil
C : Transformer
D : Permanent magnet