1) IN ALTERNATORS THE STANDARD PRACTICE NOW A DAYS IS TO HAVE a) ROTATING FIELD b) ROTATING ARMATURE c) STATIONARY FIELD d) ALL THE ABOVE 2) FOR LOW SPEED APPLICATIONS ____________________ ALTERNATOR IS USED a) SALIENT POLE b) CYLINDRICAL c) BOTH SALIENT POLE AND CYLINDRICAL d) NONE 3) HUNTING IS KNOWN AS a) LOW VOLTAGE b) MOMENTARY SPEED OSCILLATION c) SHORT CIRCUIT CURRENT d) ALL THE ABOVE 4) HUNTING IS PREVENTED BY a) INTERPOLES b) LAMINATIONS c) CYLINDRICAL ROTOR d) DAMPER WINDING 5) IN LARGE ALTERNATORS DAMPER WINDING IS USED TO IMPROVE a) SPEED b) EFFICIENCY c) STABILITY d) POWER FACTOR 6) IF WINDING SHORT PITCHED BY 30 ELECTRICAL DEGREES THEN COUL SPAN IS a) 180 electrical degree b) 160 electrical degree c) 150 electrical degree d) 0 electrical degree 7) Air gap is uniform in a) Salient pole alternator b) Cylindrical Alternator c) Both salient and cylindrical alternator d) None of the above 8) The effect of pitch factor is a) Reduces hunting b) Reduces harmonics c) Reduces power factor d) Reduces speed 9) SALIENT POLE ROTORS ARE a) SMALL IN DIAMETER AND SMALL IN AXIAL LENGTH b) LARGE IN DIAMETER AS WELL AS AXIAL LENGTH c) SMALLER IN DIAMETER AND LARGER IN AXIAL LENGTH d) LARGER IN DIAMETER AND SMALLER IN AXIAL LENGTH 10) HYDROGEN COOLING IS USED BECAUSE IT IS a) FLAMMABLE b) HIGH DENSITY c) PRESENCE OF MOISTURE d) BETTER HEAT TRANSFER CAPACITY 11) CRITICAL SPEED OF ALTERNATOR a) OCCURS WHEN SPEED IS GREATER THAN RATED SPEED b) SPEED AT WHICH VIBRATION OCCURS c) SHOULD NOT EXCEED 120% OF RATED SPEED d) ALL THE ABOVE 12) THE DISTANCE BETWEEN TWO COIL SIDES OF A COIL IS KNOWN AS a) POLE PITCH b) COIL SPAN c) PITCH FACTOR d) COIL SPAN FACTOR 13) EMF INDUCED PER PHASE IS a) MORE IN DISTRIBUTED WINDING THAN CONCENTRATED WINDING b) MORE IN CONCENTRATED WINDING THAN DISTRIBUTED WINDING c) MORE IN FULL PITCHED WINDING THAN SHORT PICHED WINDING d) BOTH B AND C 14) METHODS TO OBTAIN SINE WAVE IN SALIENT POLE ALTERNATORS ARE a) SKEWED POLE SHOE METHOD b) INDUCED CURRENT CHANGING METHOD c) DAMPER WINDINGS d) POLE CHANGING METHOD 15) Ventilation methods in turbo alternator a) Radial ventilation b) Radial axial ventilation c) Multiple inlet system d) All the above 16) In an Alternator having short pitched and concentrated winding a) Kp= 1 and Kd=1 b) Kp< 1 and Kd<1 c) Kp= 1 and Kd<1 d) Kp<1 and Kd=1

Alternator Quiz

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