Description : Which of the following converts electric energy into mechanical energy: a. Transformer b. DC generator c. Motor d. AC generator
Last Answer : d. AC generato
Description : Turn ratio of a transformer is 5. If 220 V AC is applied to its primary coil, voltage in the secondary coil will be: a. 44V b. 4.4 V c. 220V d. 1100V
Last Answer : c. 220V
Description : The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply
Last Answer : Answer: C
Description : What are the parts of a brushless AC generator?
Last Answer : Yoke, armature, stator, rotor, primary exciter, main exciter, rotary diode rectifier assembly, impeller, bearing & housing, end cover, terminal block, AVR.
Description : The only difference between construction of DC generator and Ac generator is that of: a. carbon brush b. Bar magnet c. electromagnet d. Horseshoe magnet
Last Answer : b. Bar magnet
Description : In the plane of AC generator coil is parallel to the field, then emf induced in coil is: a. maximum b. minimum c. zero d. intermediate
Last Answer : b. minimum
Description : Which one is not present in AC generator: a. Armature b. magnet c. slip ring d. commutator
Last Answer : c. slip ring
Description : The principle of AC generator is: a. Mutual induction b. self induction c. electromagnetic induction d. Induction
Last Answer : b. self induction
Description : A circuit which develops voltage across the horizontal deflection plates is known as a) Time base generator b) Electron gun c) Thermionic diode d) Zener diode
Last Answer : a) Time base generator
Description : Where is a rotor wound AC motor used?
Last Answer : For starting heavy torques, mostly used on portable machines and small winches.
Description : How can the direction of rotation of an AC motor be reversed?*
Last Answer : By interchanging any two supply lines.
Description : Explain what happens if a DC motor is fed with AC supply
Last Answer : Motor will run at low speed, sparking at brushes, heat due to eddy current will finally burn the motor.
Description : The output from a full wave rectifier is (a) A pulsating uni-directional current (b) A DC voltage (c) Zero (d) An AC voltage
Last Answer : a) A pulsating uni-directional current
Description : Why are motor ratings given in KW and that of alternator and transformer given in KVA?
Last Answer : kW is the output mechanical power of a motor and is expressed in kW. kVA is the net (apparent) power input to the transformer. This input power is the output + losses. kW = kVA x system power factor
Description : The application of mutual induction is: a. TV b. Radio c. Transformer d. Motor
Last Answer : c. Transformer
Description : What is a current transformer and voltage transformer?*
Last Answer : In electrical engineering, a current transformer (CT) is used for measurement of electric currents. Current transformers, together with voltage transformers (VT) (potential transformers (PT)), ... transformers are commonly used in metering and protective relays in the electrical power industry.
Description : The illustrated motor controller _________. EL-0023 A. is a low voltage release controller because the motor will stop when voltage falls below a certain value and automaticly start when normal voltage ... with a generator or transformer bank that is 'wye' wound with T2 connected to the neutral
Last Answer : Answer: B
Description : On AC vessels, which of the following statements represents the most difficult problem involved in obtaining a DC potential suitable for use by computer components? A. A stepdown transformer is ... voltage must be rectified and made ripple free. D. Rectifiers cannot operate with voltage regulators.
Description : What is the voltage available from each cell in a lead acid battery?
Last Answer : 2 V DC.
Description : Moisture accumulating in electric motors and generator windings having a cold insulation resistance greater than 50,000 ohms may be baked out with internal heat. This heat can be developed by ____________. ... an electric welder and feeding it into the armature while running the motor at full speed
Last Answer : Answer: A
Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections
Description : The most common source of excitation for synchronous motors is a/an ______________. A. stepup transformer B. half-wave rectifier C. DC supply D. AC supply
Description : What is a shaft generator?
Last Answer : A shaft generator is coupled to the main engine. It uses the main engine as its prime mover and has a frequency converter (thyristor controlled) that converts the variable engine speed to near constant speed and ... speed (full speed) and not at manoeuvring speed. Ask E/O and 2/E for more details.
Description : How does the emergency generator start automatically?
Last Answer : It is activated by a under voltage relay. When there is blackout, the under voltage relay senses loss of voltage and starts up the emergency generator. Similarly when the power is restored, the relay stops the emergency generator. Ask E/) for more details.
Description : After a black out the emergency generator comes on; On restoring the main supply we are closing the circuit breaker of the main generator without bothering about synchronizing. How is this possible?
Last Answer : There is a power link connection breaker between the main generator and the emergency generator. During black out, this breaker trips. The emergency generator starts and its breaker closes and feeds only ... , there is no paralleling between main and emergency generator. Ask E/O for more details.
Description : If the AVR, is defective, when additional loads come on will the generator be able to take it?
Last Answer : No. Ask E/O and refer to Dennis T Hall.
Description : If you press the ACB Close button on an idle generator what will happen?
Last Answer : Ask E/O. Normally, the breaker won’t close until you synchronise, so even if you press the breaker close, it will not close. The breaker has under-voltage protection which will not let you close it.
Description : Which component is mainly used in a DC generator: a.slip ring b. commutator c. magnet d. coil
Last Answer : b. commutator
Description : In the plane of the A.C generator coil is perpendicular to the field, then induced emf in the coil is: a. Maximum b. minimum c. zero d. intermediate value
Description : Alternating current generator converts.......... energy into electrical energy? a. mechanical energy b. chemical energy c. solar energy d. potential energy
Last Answer : a. mechanical energy
Description : The Principle of an alternating current generator is based on: a. Coulomb’s law b. Ampere’s law c. Faraday’s law d. Lenz’s law
Last Answer : a. Coulomb’s law
Description : The output waveform produced due to time base generator in a CRO is a) saw tooth b) sinusoidal c) linear d) helical
Last Answer : a) saw tooth
Description : Briefly explain how an electrical generator converts mechanical energy into electrical energy.
Last Answer : Working principle of DC generator: * Working principle of DC generator is the principle of dynamically induced emf or electromagnetic induction. * According to this principle, when flux is cut by a conductor, an ... , the flux is cut by the armature winding and an emf is dynamically induced in it.
Last Answer : Primary Idea : - First Home Type Understand AC To buy Will be That In the room AC Put it on In that If The window Stays However Likes According to Good Brand See ' window AC ' Bought To take Can. Of ... go 45 From 60 Thousands Money In The same Price In ' Gree ' Of the brand Window AC Found Will go
Description : What do we use for welding on ships? AC or DC?
Last Answer : Ask E/O on your ship.
Description : What is meant by phase in AC?
Last Answer : Two or more AC voltages or currents that are out of step with each other. Their peaks and zero points do not match up at the same points in time. This is meant by phase.
Description : Capacity of battery fuse in AC Coaches a. 315 A & 400 (HRC ) c. 16 A (HRC ) b. 63 A (HRC ) d. 5 A (HRC )
Last Answer : a. 315 A & 400 (HRC )
Description : In a half wave rectifier the rms value of AC component of the waves (a) Zero (b) Equal to DC value (c) More than DC value (d) Less than DC value
Last Answer : b) Equal to DC value
Description : The process of conversion of AC into DC is called (a) Amplification (b) rectification (c) purification (d)magnification
Last Answer : (b) rectification
Description : Alternating current (AC)
Last Answer : AC stands for Alternating Current meaning voltage or current that changes polarity or direction respectively over time. An Alternating Current (AC) is an electric current whose magnitude ... energy are known as alternators and are simpler construction than DC electromechanical generators.
Description : To couple a coaxialline toa parallel-wire line,itisbesttouse a a. slotted line b.balun c. directional coupler d. quarter-wave transformer
Last Answer : b.balun
Description : The induced current in transformer which produced in the direction perpendicular to flux, is known as: a. Conventional current b. electronic current c. Perpendicular current d. Eddy current
Last Answer : c. Perpendicular current
Description : A transformer steps down 220V to 40 volts. If the secondary turns are 40 then primary turns will be: a. 20 b. 40 c. 120 d. 220
Last Answer : d. 220V
Description : The loss of energy over each A.C cycle magnetization and demagnetization of transformer, is called: a. Magnetization loss b. Hysteresis loss c. Demagnetization loss d. energy loss
Last Answer : c. Demagnetization loss
Description : An ideal transformer always obeys the law of conservation of........: a. energy b. momentum c. charge d. Flux
Last Answer : b. momentum
Description : A transformer: a. Works on A.C. only b. Works on D.C only c. Works on A.C. and D.C d. Has no hysteresis loss
Last Answer : a. Works on A.C. only
Description : To construct a step down transformer, the condition is: a. Ns > Np b. Np > Ns c. Np = Ns d. Np . Ns = 1
Last Answer : c. Np = Ns
Description : Eddy currents produced in the core of transformer are responsible for: a. heat loss b. Step up process c. Step down process d. induction phenomena
Last Answer : d. induction phenomena
Description : Explain the electrical characteristics of transformer.
Last Answer : Transformer electrical characteristics: Area of primary and secondary conductors, Apri and Asec: Winding loss Pw: Flux density and core loss: Leakage inductance: ... transformer span. The rise in temperature may breakdown insulation which may cause failure of the transformer.
Last Answer : The efficiency of transformer is Greater than electrical Machine because there is no rotational losses in transformer and there is no air gap losses in transformer so losses is less in transformer compare to electrical machine so efficiency is higher in case of transformer.