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This set of Electrical and Electronics Engineering Multiple Choice Questions & Answers (MCQs) focuses on Electrical And Electronics Engineering Set 2
Q1 | The basic requirement of a dc armature winding is that it must be
- a closed one
- a lap winding
- a wave winding
- either b or c
Q2 | The sole purpose of a commutator in a dc generator is to
- increase output voltage
- reduce sparking at brushes
- provide smoother output
- convert the induced ac into dc
Q3 | In a dc generator, the generator, the generated emf is directly proportional to the
- field current
- pole flux
- number of armature parallel paths
- number of dummy coils
Q4 | Voltage equation of a dc motor is
- v = eb + iara
- eb = v + iara
- v = eb/iara
- v = eb + ia2ra
Q5 | which of the following motor has the constant speed?
- series motor
- shunt motor
- cumulatively compound motor
- all of the above
Q6 | The usual test to find the efficiency of the traction motor is
- field\s test
- retardation test
- hopkinson\s test
- swinburn\s test
Q7 | A DC series motor is best for driving
- lathes
- cranes and hoists
- shears and punches
- machine tools
Q8 | In a DC series motor increasing the load current will
- decrease the speed
- increase the speed
- better commutation
- increase the back emf
Q9 | The DC motor, which can provide zero speed regulation at full load without any controller is
- series
- shunt
- cumulative compound
- differential compound
Q10 | In 8 - pole wave connected motor armature, the number of parallel paths are
- 8
- 4
- 2
- 1
Q11 | The speed of a dc motor can be controlled by varying
- its flux per pole
- resistance of armature circuit
- applied voltage
- all of the above
Q12 | The d.c. series motor should always be started with load because
- at no load, it will rotate at dangerously high speed.
- it will fail to start.
- it will not develop high starting torque.
- all are true.
Q13 | In a d.c. machine, the armature mmf is
- stationary w.r.t. armature.
- rotating w.r.t. field.
- stationary w.r.t. field.
- rotating w.r.t. brushes.
Q14 | In a DC motor, unidirectional torque is produced with the help of
- brushes
- commutator
- end-plates
- both a and b
Q15 | The counter emf of dc motor
- often exceeds the supply voltage
- aids the applied voltage
- helps in energy conversion
- regulates its armature voltage
Q16 | The Eb/V ratio of a dc motor is an indication of its
- efficiency
- speed regulation
- starting torque
- running torque
Q17 | The induced emf in the armature conductors of a dc motor is
- sinusoidal
- trapezoidal
- rectangular
- alternating
Q18 | A dc motor can be looked upon as dc generator with the power flow
- reduced
- reversed
- increased
- modified
Q19 | The Ta/Ia graph of a dc series motor is a
- parabola from no load to overload
- straight line throughout
- parabola throughout
- parabola upto full load and a straight line at overloads
Q20 | When load is removed, .......motor will run at the highest speed.
- shunt
- cumulative - compound
- differential compound
- series
Q21 | In Fleming's right-hand rule, the thumb point towards
- direction of flux
- direction of induced e.m.f.
- direction of motion of conductor, if fore finger points along the lines of flux
- direction of motion of the conductor\ if fore finger point in the direction of generated e.m.f.
Q22 | . The armature of a dc machine is made of____.
- silicon steel
- wrought iron
- cast steel
- soft iron
Q23 | The yoke of a d.c. machine is made of ____.
- silicon steel
- soft iron
- aluminum
- cast steel
Q24 | . The coupling field electrical and mechanical systems of dc machine is____.
- electric field
- magnetic field
- both electric and magnetic fields
- mechanical field
Q25 | The real working part of a dc machine is the ___.
- commutator
- field winding
- armature winding
- none of the above