Description : Magnetic flux linked with a coil can be changed by using an: a. Permanent magnet b.Bar magnet c. Electromagnet d. Horseshoe magnet
Last Answer : b.Bar magne
Description : Which component is mainly used in a DC generator: a.slip ring b. commutator c. magnet d. coil
Last Answer : b. commutator
Description : Which one is not present in AC generator: a. Armature b. magnet c. slip ring d. commutator
Last Answer : c. slip ring
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 : In an AC generator, direct current from a separate source is passed through the windings of the rotor _____________. A. by means of slip rings and brushes B. by means of a commutator C. by means of rotating bar magnet D. to minimize the danger of arc over
Last Answer : Answer: A
Description : The most common type of AC service generator found aboard ship is the stationary _____________. A. electromagnetic field, revolving armature type B. electromagnetic field, oscillatory armature type C. armature, oscillatory electromagnet field type D. armature, rotating electromagnetic field type
Last Answer : Answer: D
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 : 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 : The most common source of AC voltage is: a. motor b. generator c. cell d. transformer
Last Answer : c. cell
Description : The principle of AC generator is: a. Mutual induction b. self induction c. electromagnetic induction d. Induction
Last Answer : b. self induction
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 : What do we use for welding on ships? AC or DC?
Last Answer : Ask E/O on your ship.
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 : 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 : On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above this are obtained by _____________. A. rotating brush ... B. raising the generator engine speed C. lowering the generator engine speed D. decreasing excitation
Last Answer : Answer: B
Description : What is a brush less alternator?
Last Answer : A brushless alternator is composed of two sections: main alternator and the smaller exciter. The exciter has stationary field coils and a rotating armature (power coils). The main alternator ... has a rotating field as described above and a stationary armature (power generation windings).
Description : How is an electromagnet different from a permeant magnet?
Last Answer : Mainly in that the electromagnet is NOT permanent. In otherwords, it can be switched on and off.Another relevant difference isthat the electromagnet constantly requires power, at least while itis on.
Description : Induced current in coil by a magnet turns it into an A. straight wire B. magnet C. ammeter D. electromagnet
Last Answer : electromagnet
Description : What is permanent magnet and electromagnet?
Last Answer : Permanent magnet: A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. As the name suggests, a permanent magnet is 'permanent'. ... an electric current passes through the coil. If the current is interrupted, the magnetism is lost.
Description : Write one application of each: i) Permanent Magnet ii) Electromagnet
Last Answer : i) Applications of Permanent Magnet: 1) Field of DC motors 2) Tacho-generators 3) In stepper motors. 4) Field of two wheeler and car dynamo 5) In magnetic therapy 6) ... Motors, Generators, Transformers, Electromagnetic Relays, Circuit breakers, Traction, Measuring instruments, Electrical Bell etc.
Description : In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings
Description : What is the function of brush in DC generator ?
Last Answer : The brush on the DC generator looks a lot like a rectangle. The brush is used for contacts that supply the output. It is made of carbon graphite.
Description : Insufficient brush pressure on a DC motor may cause _______. A. generator overload B. excess residual magnetism C. water vapor absorption D. sparking of the brushes
Description : The direction of magnetic lines of force is (a) from south pole to north pole (b) from north pole to south pole (c) from one end of the magnet to another (d) none of the above
Last Answer : (b) from north pole to south pole
Description : A permeable substance is one (a) which is a good conductor (6) which is a bad conductor (c) which is a strong magnet (d) through which the magnetic lines of force can pass very easily
Last Answer : (d) through which the magnetic lines of force can pass very easily
Description : The most suitable metal for making permanent magnet is a) Iron b) Steel c) Silver d) Copper
Last Answer : a) Iron
Description : In motor a permanent magnet provides: a. Electric field b. electric flux c. magnetic field d. gravitational field
Last Answer : d. gravitational field
Description : The pole faces of U-shaped magnet in a moving coil galvanometer are made concave to a) decrease the strength of magnetic field b) create a non-uniform magnetic field c) make the magnetic field radial d) All of these
Last Answer : c) make the magnetic field radial
Description : 4. The essential difference between an AC generator and a DC generator is that -Physics-10
Last Answer : AC generator has slip rings while the DC generator has a commutator. AC generators have two rings known as the slip rings while DC generators have two half rings known as the commutator. This is main difference between AC generator and DC generator.
Description : What is the difference between an AC and DC generator?
Last Answer : The generator which generates DC voltage is called DC generator and generator which generates AC voltage is called AC generator (or) Alternator. In DC generator armature is rotated and field winding ... generator. A DC generator can generate low voltages but an AC generator can generate upto 11kv.
Description : Why is it necessary that incoming alternator frequency is more than bus bar?
Last Answer : Prior to paralleling alternators together, the frequency of the incoming alternator is made slightly higher. This is to ensure that the incoming generator will take some of the bus load. If the incoming ... onto the bus. If this happens it is possible to cause other generators to trip off line.
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 : 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 : 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 : 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.
Description : What are the basic parts of a DC motor?*
Last Answer : Rotor and stator, field poles, commutator, brushes, fan impeller, bearing & housing, end covers and name plate.
Description : How is the speed of a DC motor varied?
Last Answer : To vary the speed of a DC motor we need a constant voltage power supply with a series POT resistor of higher watt rating. A Pulse Width Modulator (PWM) can be used.
Description : Why is DC not much in use now?
Last Answer : AC generators are a better technology and voltage transformation (by transformers) is easy is possible in AC and not DC.
Description : Is there phase in DC?
Last Answer : No
Description : Direct Current (DC) Next Topic : Alternating current (AC)
Last Answer : Direct Current (DC) is the unidirectional electric current. Uni meaning is one. And the flow of charge in same direction. We know that conventional current flow from positive terminal of battery to ... The magnitude of DC may constant or vary but direction do not change with respect to time.
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
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