1. The main objective in designing a synchronous machine is to:
(A) Obtain desired voltage, power factor, and efficiency with minimum cost and weight
(B) Increase weight and size
(C) Reduce efficiency intentionally
(D) Ignore cooling requirements
2. The two main parts of a synchronous machine are:
(A) Stator and rotor
(B) Armature and commutator
(C) Field coil and brushes
(D) Shaft and bearings
3. The stator of a synchronous machine carries:
(A) Armature winding
(B) Field winding
(C) Commutator
(D) Permanent magnets
4. The rotor of a synchronous machine carries:
(A) Field winding
(B) Armature winding
(C) Stator core
(D) End shields
5. The field winding of a synchronous machine is usually excited by:
(A) DC supply
(B) AC supply
(C) Induced voltage
(D) Permanent magnet
6. The rotor construction of a synchronous machine can be:
(A) Salient pole or cylindrical type
(B) Squirrel cage or wound type
(C) Laminated or solid
(D) Shaded pole type
7. The salient pole rotor is generally used for:
(A) Low-speed machines
(B) High-speed machines
(C) Turbo-generators
(D) DC machines
8. The cylindrical rotor is used for:
(A) High-speed alternators
(B) Low-speed alternators
(C) DC machines
(D) Servo motors
9. The air gap in a synchronous machine is kept:
(A) Small to reduce magnetizing current
(B) Large to improve cooling
(C) Large to increase reactance
(D) Variable to change flux
10. The stator core is laminated to:
(A) Reduce eddy current losses
(B) Increase flux density
(C) Increase strength
(D) Improve cooling
11. The exciter in a synchronous machine is used to:
(A) Supply DC to the rotor field winding
(B) Start the machine
(C) Control frequency
(D) Reduce copper losses
12. The synchronous speed of a machine depends on:
(A) Supply frequency and number of poles
(B) Supply voltage
(C) Excitation current
(D) Load current
13. The armature reaction in a synchronous machine affects:
(A) The main field flux
(B) The mechanical losses
(C) The insulation strength
(D) The shaft alignment
14. The voltage regulation of a synchronous generator depends on:
(A) Armature resistance and reactance
(B) Shaft speed only
(C) Load type only
(D) Air-gap size only
15. The output equation of a synchronous machine relates:
(A) Power developed to specific magnetic and electric loadings
(B) Voltage to frequency
(C) Torque to flux
(D) Current to power factor
16. The specific magnetic loading in synchronous machine design refers to:
(A) Average flux density in the air gap
(B) Armature current density
(C) Field current
(D) Power factor
17. The specific electric loading refers to:
(A) Total current per meter of armature periphery
(B) Flux per pole
(C) Armature resistance
(D) Field excitation current
18. Increasing magnetic loading generally:
(A) Reduces machine size but increases core losses
(B) Increases cooling efficiency
(C) Decreases copper losses
(D) Reduces armature reaction
19. Increasing electric loading results in:
(A) Increased copper losses and temperature rise
(B) Reduced output
(C) Improved voltage regulation
(D) Reduced losses
20. The short-circuit ratio (SCR) of a synchronous machine indicates:
(A) Stability and voltage regulation
(B) Efficiency only
(C) Speed range
(D) Cooling capacity
21. A high SCR means:
(A) Better voltage regulation and higher stability
(B) Poor stability
(C) Low excitation requirement
(D) Increased losses
22. The armature winding of a synchronous machine is usually:
(A) Three-phase distributed winding
(B) Concentrated winding
(C) DC winding
(D) Single-phase winding
23. The damper winding in a synchronous machine is provided to:
(A) Reduce hunting and assist starting
(B) Improve efficiency
(C) Increase field flux
(D) Reduce temperature rise
24. The field winding is generally made of:
(A) Copper wire insulated with varnish
(B) Aluminum wire
(C) Steel strip
(D) Carbon fiber
25. The cooling of large alternators is achieved by:
(A) Hydrogen or water cooling systems
(B) Natural air only
(C) Oil immersion
(D) Closed circuit air alone
26. The efficiency of large synchronous machines is usually:
(A) 95% to 98%
(B) 60% to 70%
(C) 75% to 80%
(D) 50% to 55%
27. The excitation system of modern alternators is often:
(A) Brushless type for reliability
(B) DC commutator type
(C) Slip ring based only
(D) Static only
28. The pole shoe in a salient pole machine is used to:
(A) Distribute flux uniformly in the air gap
(B) Support the shaft
(C) Improve commutation
(D) Increase eddy currents
29. The reactances considered in synchronous machine design are:
(A) Armature, leakage, and synchronous reactances
(B) Only leakage reactance
(C) Capacitive reactance
(D) Frequency reactance
30. The overall design goal of a synchronous machine is to:
(A) Achieve optimum efficiency, reliability, and voltage regulation at minimum cost
(B) Increase weight and cost
(C) Reduce lifespan
(D) Ignore ventilation design