Description : The direction of rotation of an inverter fed 3-phase ac motor is reversed by (A) a mechanical reversing switch (B) reversing the input dc link voltage (C) operating the inverter as a rectifier (D) changing the sequence of switching
Last Answer : The direction of rotation of an inverter fed 3-phase ac motor is reversed by changing the sequence of switching
Description : If the connections for the field and the armature on a DC motor are reversed, _____________. A. the motor will run as a generator B. the motor will not run C. the direction of rotation will be the same D. the direction of rotation will be reversed
Last Answer : Answer: C
Description : Which of the listed conditions will occur if the polarity of the field poles and the direction of current to the brushes of a DC motor were both reversed? A. The motor would not start. ... direction of rotation of the armature would be unchanged. D. The field pole windings would become overheated.
Description : The direction of rotation of a DC propulsion motor can be reversed by __________. A. reversing the field connections B. reversing the field and the armature connections C. wiring the field and armature in parallel D. wiring the field and armature in series
Last Answer : Answer: A
Description : Which of the following statements describes what will happen when both the polarity of the field poles, and the direction of current to the brushes of a DC motor are reversed? A. The motor will ... of rotation of the armature will remain the same. D. The field pole windings will become overheated.
Description : The direction of rotation of hysteresis motor is reversed by (A) Shift shaded pole with respect to main pole (B) Reversing supply lead (C) Either A or B (D) Neither A nor B
Last Answer : Ans: A This motor used single phase, 50Hz supply and stator has two windings. These are connected continuously from starting to running.
Description : Direction of rotation of three phase induction motor can be reversed by (a) interchanging connections of any two phases (b) disconnecting any one phase (c) (a) and (b) both (d) None of the above
Last Answer : The direction of rotation of 3-phase induction motor is reversed by Changing the phase sequence of supply. OR The direction of rotation of 3-phase induction motor is reversed by inter-changing any two phase connections of motor terminals with supply terminals.
Last Answer : The direction of rotation of universal motor can be reversed the by reversing the flow of current through either armature winding or field winding.
Last Answer : Direction of rotation of a split phase motor can be reversed by reversing the connection of either running winding or starting winding.
Description : How is the direction of rotation varied?
Last Answer : By changing the phase sequence (from say R-Y-B to R-B-Y)
Description : When 220V dc shunt alternator generating the voltage at rated value. If direction of rotation is reversed, then alternator will a) Build up its voltage with same polarity b) Build up its voltage with opposite polarity c) No build up of voltage d) None
Last Answer : Ans: No build up of voltage
Description : What two receiver leads are reversed to reverse the rotor's direction of rotation?
Last Answer : 1 and S3.
Description : To reverse the direction of rotation of a three-phase AC induction motor, do one of the following: w) reverse any two of the three-phase connections x) change the frequency of the applied AC power y) operate the motor below the stall torque at very high slip z) none of the above
Last Answer : ANSWER: W -- REVERSE ANY TWO OF THE THREE-PHASE CONNECTIONS
Description : A light emitting diode emits light only when (a) Reversed biased (b) forward biased (c) unbiased (d) none
Last Answer : (b) forward biased
Description : P-n junction when reversed biased acts as a (a) Capacitor (b) inductor (c) on switch (d) off switch
Last Answer : d) off switch
Description : Where is a rotor wound AC motor used?
Last Answer : For starting heavy torques, mostly used on portable machines and small winches.
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 : 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 : The most common source of AC voltage is: a. motor b. generator c. cell d. transformer
Last Answer : c. cell
Description : Which statement is true concerning a split-phase induction motor? A. Motor rotation can be reversed without changing the windings or leads. B. Motor speed can be readily adjusted from zero to full ... proper wiring. D. Motor rotation can be reversed by reversing the leads on the starting winding.
Last Answer : Answer: D
Description : The rotation of a three-phase induction motor can be reversed by _____________. A. interchanging any two of the three line leads to the stator B. disconnecting one of the three line leads to the ... the shunt field coil leads D. permanently disconnecting any two of the three line leads to the stator
Description : How the speed of rotation of a split phase induction motor is reversed?
Last Answer : The terminal connections of the starting windings are reversed with respect to main running windings..
Description : Indicatewhich one ofthe followingterms appliestotroposcatter propagation: a. SIDs b.Fading c. Atmospheric storms d. Faraday rotation
Last Answer : b.Fading
Description : How does this cause a rotation to change?
Last Answer : Due to the change in phase sequence, the rotating magnetic field changes direction and the rotor rotates in the opposite direction.
Description : How is the direction of a capacitor start Induction motor be reversed?
Last Answer : The direction of rotation can be reversed by interchanging the terminals of either the main winding or the starting winding.
Description : Which of the synchroscope illustrations depicts the appropriate direction of rotation and position for closing the circuit breaker when paralleling AC generators? EL-0053 A. A B. B C. C D. D
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 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 : 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 : 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 : 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 : 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 : 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 : The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, ... and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor
Last Answer : (d) current, magnetic field and direction of force on a conductor
Description : Fleming's left hand rule is used to find (a) direction of magnetic field due to current carrying conductor (b) direction of flux in a solenoid (c) direction of force on a current carrying conductor in a magnetic field (d) polarity of a magnetic pole
Last Answer : (c) direction of force on a current carrying conductor in a magnetic field
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 : Electromagneticwaves are refractedwhen they a. pass into a medium of different dielectric constant b. are polarized at right angles to the direction of propagation c. encounter a perfectly conducting plane d. pass through a small slot in a conducting plane
Last Answer : a. pass into a medium of different dielectric constant
Description : The direction of induced EMF can be found with the help of -
Last Answer : Lenz’s Law
Description : Sometimes, when you change the running direction of a E/R blower (from supply to exhaust) it trips. Why?
Last Answer : If the flaps of the blower are not set or opened properly or the filters are clogged, the air supply is affected and the blower may be overloaded causing it to trip. Ask E/O for more information.
Description : How is the direction varied?
Last Answer : A general purpose DC motor can be reversed by changing the polarity of either the armature or the field but not both.
Description : The emission in which the atom emits a photon of energy hf = E2 – E1 , in any arbitrary direction is a) Spontaneous emission b) stimulated emission c) induced emission d) both a & c
Last Answer : d) both a & c
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 magnetic field acts on a charged particles so as to change its: a. speed b. energy c. direction of motion d. all of these
Last Answer : Only direction of motion will change ...it means velocity will change but speed same