UPDA QATAR

SYNCHRONOUS MOTOR Synchronous Motors 1.   Synchronous motor can operate at (A) Lagging   power factor   only (B) Leading power factor only (C)   Unity power factor   only (D) Lagging, leading and unity power factor only. D 2.   An unexcited single phase   synchronous motor   is (A) reluctance motor (B) repulsion motor (C) universal motor (D) AC series motor. A 3.   The maximum power developed in the synchronous motor will depend on (A) rotor excitation only (B) maximum value of coupling angle (C) supply voltage only (D) rotor excitation supply voltage and maximum value of coupling angle. D 4.   In   case the field of a synchronous motor is under excited, the power factor will be (A) leading (B) lagging (C) zero (D) unity. B 5.   A   synchronous motor is switched on to supply with its field windings shorted on themselves. It will (A) not start (B) st...

ELECTRONICS Electronic Devices  Objective  Questions [1] For harmonic generation the amplifier used is a)Audio Amplifier b)Class-A Amplifier c)RC Amplifier d)class-C Turned Amplifier Ans:D Answer [2] Zener diodes semiconductors are a)Lightly Doped b)Heavily Doped c)Medium Doped d)Not at all Doped Ans: B Answer [3] In FET amplifiers, input is Incorrect! a)A current signal b)A voltage signal c)Either a current or voltage signal d)None of these Ans: B Answer [4] H-parameters of a transistor a)Are constant b)Vary with temperature c)Are dependent upon collector current d)None of these Ans:C Answer [5] In a voltage series feedback a)Output resistance increases while input resistance decreases b)Output and input resistances are reduced c)Output and input resistances are increased d)Output resistance decreases while input resistance increases Ans: B Answer [6]In a saturated transistor a)B-E junction is forward biased with C-B junction is re...

Electrical drives(Cranes ) 1.  The consideration involved in the selection of the type of electric drive for a particular application depends on (A) Speed control range and its nature (B) Starting torque (C) Environmental conditions (D) All of the above. Get Answer:   D 2.  Which of the following is preferred for automatic drives ? (A) Synchronous motors (B) Squirrel cage  induction motor (C) Ward Leonard controlled dc motors (D) Any of the above. Get Answer:  (Show) C 3.  Which type of drive can be used for hoisting machinery (A) AC  slip ring motor (B) Ward Leonard controlled DC  shunt motor (C) DC compound motor (D) Any of the above. Get Answer:  (Hide) D 4.  The motor normally used for crane travel is (A) AC slip ring motor (B) Ward Leonard controlled DC shunt motor (C)  Synchronous motor (D) DC differentially compound motor. Get Answer:   A 5...