Question 1. What Is Slip In An Induction Motor?
Slip can be described as the distinction between the flux pace (Ns) and the rotor speed (N). Speed of the rotor of an induction motor is usually less than its synchronous velocity. It is commonly expressed as a percentage of synchronous velocity (Ns) and represented with the aid of the symbol 'S'.
Question 2. What Are The Various Kind Of Cables Used For Transmission?
Cables, that are used for transmitting energy, can be categorised in 3 bureaucracy:
Low-anxiety cables, that can transmit voltage upto one thousand volts.
High-anxiety cables can transmit voltage upto 23000 volts.
Super anxiety cables can transmit voltage sixty six kV to 132 kV.
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Question three. How Can You Relate Power Engineering With Electrical Engineering?
Power engineering is a sub department of electrical engineering. It offers with technology, transmission and distribution of energy in electrical form. Design of all strength equipments additionally comes beneath power engineering. Power engineers may work at the layout and preservation of the electricity grid i.E. Called on grid structures and they may work on off grid systems that are not connected to the machine.
Question four. Why Star Delta Starter Is Preferred With Induction Motor?
Star delta starter is preferred with induction motor due to following motives:
Starting contemporary is reduced 3-four times of the direct modern-day because of which voltage drops and for this reason it causes less losses.
Star delta starter circuit is available in circuit first at some stage in starting of motor, which reduces voltage three instances, this is why present day also reduces up to a few instances and consequently less motor burning is caused.
In addition, starting torque is elevated and it prevents the damage of motor winding.
Question five. Explain State Thevenin's Theorem?
According to thevenin's theorem, the contemporary flowing thru a load resistance
Connected throughout any terminals of a linear lively bilateral community is the ratio open circuit voltage (i.E. The voltage across the two terminals while RL is removed) and sum of load resistance and inner resistance of the community. It is given through Voc / (Ri + RL).
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Question 6. Tell Me What Are The Different Methods For The Starting Of A Synchronous Motor?
Starting strategies: Synchronous motor can be started out by the following two methods:
By approach of an auxiliary motor: The rotor of a synchronous motor is turned around by way of auxiliary motor. Then rotor poles are excited due to which the rotor subject is locked with the stator-revolving field and continuous rotation is obtained.
By imparting damper winding: Here, bar conductors are embedded inside the outer periphery of the rotor poles and are short-circuited with the short-circuiting rings at each aspects. The device is started as a squirrel cage induction motor first. When it alternatives up speed, excitation is given to the rotor and the rotor starts offevolved rotating constantly as the rotor area is locked with stator revolving area.
Question 7. Explain State Norton's Theorem?
The Norton's theorem explains the fact that there are two terminals and they're as follows:
One is terminal energetic community containing voltage resources
Another is the resistance that is considered from the output terminals. The output terminals are equal to the regular source of current and it lets in giving the parallel resistance.
The Norton's theorem additionally explains approximately the steady modern this is same to the modern-day of the quick circuit positioned across the terminals. The parallel resistance of the community can be considered from the open circuit terminals when all of the voltage and present day sources are eliminated and replaced by way of the internal resistance.
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Question 8. Tell Me What Is Your Work Experience As Electrician Assistant?
Employers are searching out constant paintings employment and no longer brief term assignments and large gaps among jobs. You should be organized to provide an explanation for any gaps among jobs. Another piece of recommendation is to recognition on paintings experience applicable to the position you are presently applying for as well as your most latest paintings records.
Question 9. Explain Advantages Of Storage Batteries?
Few advantages of storage batteries are noted under:
Most efficient shape of storing power portably.
Stored electricity is available right away because there is no lag of time for delivering the stored power.
Reliable source for supply of power.
The strength may be drawn at a reasonably steady fee.
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Question 10. How Does Zener Phenomenon Differ From Avalanche Breakdown?
The phenomenon whilst the depletion area expands and the capacity barrier increases leading to a totally high electric field throughout the junction, due to which unexpectedly the opposite modern-day will increase underneath a completely excessive opposite voltage is called Zener impact. Zener-breakdown or Avalanche breakdown can also arise independently or both of these may occur simultaneously. Diode junctions that breakdown below 5v are due to Zener Effect. Junctions that enjoy breakdown above 5v are due to avalanche-impact. The Zener-breakdown occurs in closely doped junctions, which produce slim depletion layers. The avalanche breakdown occurs in lightly doped junctions, which produce huge depletion layers.
Question eleven. Name Some Types Of Motors Used In Vacuum Cleaners, Phonographic Appliances, Vending Machines, Refrigerators, Rolling Mills, Lathes, Power Factor Improvement And Cranes?
Following cars are used: -
Vacuum cleaners- Universal motor.
Phonographic appliances - Hysteresis motor.
Vending machines - Shaded pole motor.
Refrigerators - Capacitor break up section vehicles.
Rolling mills - Cumulative motors.
Lathes - DC shunt vehicles.
Power element development - Synchronous cars
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Question 12. Explain The Forward Resistance, Static Resistance And Dynamic Resistance Of A Pn Junction Diode?
Forward Resistance: Resistance presented in a diode circuit, while it's miles forward biased, is known as ahead-resistance.
DC or Static Resistance: DC resistance may be explained as the ratio of the dc-voltage throughout the diode to the direct contemporary flowing through it.
AC or Dynamic Resistance: It can be defined because the reciprocal of the slope of the forward characteristic of the diode. It is the resistance supplied by a diode to the changing ahead present day.
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Question 13. Why Ac Systems Are Preferred Over Dc Systems?
Due to following reasons, AC structures are desired over DC structures:
It is straightforward to preserve and trade the voltage of AC strength for transmission and distribution.
Plant value for AC transmission (circuit breakers, transformers and so on) is plenty lower than the equal DC transmission
From energy stations, AC is produced so it's far higher to use AC then DC rather than converting it.
When a huge fault happens in a community, it is less difficult to break in an AC gadget, because the sine wave cutting-edge will evidently tend to 0 sooner or later making the contemporary easier to interrupt.
Question 14. Explain Thin Film Resistors And Wire-wound Resistors?
Thin film resistors- It is constructed as a thin film of resistive material is deposited on an insulating substrate. Desired outcomes are received with the aid of both trimming the layer thickness or through cutting helical grooves of suitable pitch alongside its length. During this process, the cost of the resistance is monitored closely and slicing of grooves is stopped as soon because the desired price of resistance is obtained.
Wire wound resistors - length of twine wound around an insulating cylindrical middle are called wire wound resistors. These wires are fabricated from substances together with Constantan and Manganin due to their high resistivity, and occasional temperature coefficients. The whole wire wound resistor is covered with an insulating fabric together with baked tooth.
Question 15. Explain And Compare Jfet's And Mosfet's?
Comparison of JFET's and MOSFET's:
JFET's can handiest be operated within the depletion mode while MOSFET's can be operated in both depletion or in enhancement mode. In a JFET, if the gate is forward-biased, extra-provider injunction occurs and the gate-modern is widespread.
MOSFET's have enter impedance much higher than that of JFET's. Thus is due to negligible small leakage current.
JFET's have function curves more flat than that of MOSFET is indicating a higher drain resistance.
When JFET is operated with a reverse-bias on the junction, the gate-cutting-edge IG is bigger than it might be in a comparable MOSFET.
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Question 16. Explain Cmrr, And What Is A Differential Amplifier?
Differential Amplifier: The amplifier, which is used to amplify the voltage distinction between two input-lines neither of which is grounded, is known as differential amplifier. This reduces the amount of noise injected into the amplifier, because any noise acting simultaneously on each the input-terminals because the amplifying circuitry rejects it being a commonplace mode signal.
CMRR: It may be defined because the ratio of differential voltage-advantage to not unusual made voltage benefit. If a differential amplifier is best, CMRR might be limitless due to the fact if so commonplace mode voltage advantage would be 0.
Question 17. Explain The Application Of Storage Batteries?
Storage batteries are used for numerous purposes, some of the applications are stated under:
For the operation of protecting gadgets and for emergency lighting at producing stations and substations.
For beginning, ignition and lighting of cars, aircrafts and many others.
For lighting on steam and diesel railways trains.
As a deliver power source in smartphone change, laboratories and huge casting stations.
For emergency lights at hospitals, banks, rural areas where energy supplies aren't feasible.
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Question 18. State The Difference Between Generator And Alternator?
Generator and alternator are devices, which converts mechanical power into electrical strength. Both have the same principle of electromagnetic induction, the simplest difference is that their construction. Generator persists stationary magnetic subject and rotating conductor which rolls at the armature with slip earrings and brushes driving against every other, as a result it converts the precipitated emf into dc cutting-edge for outside load whereas an alternator has a stationary armature and rotating magnetic area for high voltages however for low voltage output rotating armature and stationary magnetic discipline is used.
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Question 19. Why Are You Interested In The Electrician Trade?
If you are new to the electrical change or are applying for an apprenticeship, you'll probably be requested this question. Employers ask this question because they want to pay attention your motivations and dreams so that may be positive that you absolutely have an interest within the subject.
Question 20. Explain State Maximum Power Transfer Theorem?
The Maximum strength transfer theorem explains approximately the weight that a resistance will extract from the community. This consists of the most electricity from the community and in this case the load resistance is being is identical to the resistance of the network and it additionally permits the resistance to be same to the resistance of the network. This resistance can be considered by way of the output terminals and the strength resources can be eliminated by way of leaving the internal resistance behind.
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Question 21. Why Back Emf Used For A Dc Motor? Highlight Its Significance?
The precipitated emf advanced when the rotating conductors of the armature between the poles of magnet, in a DC motor, reduce the magnetic flux, opposes the contemporary flowing thru the conductor, while the armature rotates, is referred to as back emf. Its cost depends upon the speed of rotation of the armature conductors. In starting, the value of lower back emf is zero.