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Why Transistors are not used as switching devices?
Dr. Raman
- Jul 28th, 2006
This is not a correct question. If an interviewer asks you, you should ask in return what kind of transistor are you talking about? Is it MOSFET, BJT, THYRISTOR etc. All semiconductor transistors are used as switching devices depending upon the application.
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What is the main Electrical IS rules?.
yuvaraj moorthy
- Mar 25th, 2010
ISO is international standard organisation and IS is Indian standarad ...ISO has IEC which is International Electrotechnical Commision will do the standarad for all equipments and each national interp...
vishwas_deshmukh
- May 6th, 2008
IS rules is international standrds rule adopted for any comissioning,erection,or any work we want to perform.They have some certain standads according to study of researcher by comparing all geographical and availabe technical parameteres in that concerning area.Which is suitable for any work.
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How to Simulate an Induction motor?
jatin patel
- Oct 16th, 2007
Transformer with secondary shorted is simulation of sq. cage induction motor
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What is the resistance between neutral and earth.
RAJA.P
- Dec 29th, 2011
The difference between the earth and neutral is 0.8 or below 1
bittu123
- Nov 8th, 2011
If neutral is grounded, resistance bet earth and neutral will be ideally 0 (zero). or very low depends what conductor is used to connect neutral with earth.
If neutral is not grounded, resistance will depend on atmospheric condition and air density, will be very high, tends to infinity -
What is the difference between P,PI,PID CONTROLLER?
harry4u
- Sep 8th, 2008
The difference lies in the action of the controllerspd-helps in achieving steady state conditions quickly.pi-helps in reducing steady state errorpid-helps in reducing sready state eror and also getting steady state conditions quickly
nagaseshareddy
- Sep 19th, 2007
The difference is shows the name itselfP-proportional controlPI- proportional with integral controlPID-proportional with integral and dervitave controlHope this help you
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What is the effect of pole slipping in generator and how it will slip?
Hashim
- Jan 19th, 2017
What happens on generator connected with grid if grid frequency increases or decreases
expertnayak
- Jun 12th, 2009
Pole slipping typically occurs under severe fault conditions which cause a transient torque on the generator which exceeds the ability of the field to hold the generator rotor synchronised to the stat...
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How much should be the insulation resistance value of a 5KW motor and 50KW motor?
AJAY KUMAR PANDEY
- Jan 12th, 2009
IR value does not depend on KW. IR value depends on supply voltage.
haveasafeday
- Feb 5th, 2008
Insualtion resistance(IR) value of a motor does not depend upon rating(i.e. KW). It is depend upon Voltage label in which it applied.There is a example:If V=415v then IR should be min. 1.415 MohmAnd if V=6.6kv IR should be min. 7.6 Mohm
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Explain the operation of a transistor
behera.tapan
- Nov 22nd, 2009
Generally there are three mode of transistor operation .1. Common emmiter2. Common collector.3. Common base.For example in common base connection make base is common with respect to (wrt)emmiter and c...
behera.tapan
- Nov 19th, 2009
Generally there are three mode of transistor operation .1. Common emmiter2. Common collector.3. Common base.For example in common base connection make base is common with respect to (wrt)em...
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What is the use of control panels in transmission systems?
RAVI KUMAR
- Sep 14th, 2011
control panels are used in substations ... use is for monitoring of power system... controlling of real and reactive power flow is also done from the control panel... in case of occurrence of fault...
rahulr30
- Jun 8th, 2008
Control Panels literally help in controlling power supplied. It helps in protection and cntrols the various CBs and other protection Equipments. It hac Current relays etc to sense the current.I also helps to pinpoint the location of faults in feeders.
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Tranmission and Distribution
Why are we employing star type transformer at transmission end and delta type transformer at receiving end?
luckwithme
- Jul 11th, 2008
Delta star transformer used in distribution purpose because of earthfault on star side do no reflect on delta side of winding. Zero phase current is eleminated in delta side of transformer and another...
chinnakalupukuri
- Apr 11th, 2008
by having the y-type on receiving end, we can get 3-phase,3-wire supply or 3-phase,4-wire supply.we can also get 1-phase supply.b'coz in y-type we have neutral point.whereas in delta type transfor...
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Potentiometer and Rheostat
What is difference between potentiometer and rheostat?
bittu123
- Nov 9th, 2011
Rheostate is variable resistance has only two leads. potentiometer differs in working principal as it has three leads and works on potential divider method
s.v.vijayaraj
- Mar 31st, 2008
The difference between potentiometer and rheostat is that the potentiometer can be used for high range of?voltage and current but the rheostat cannot be used for high range of voltage or current.?Size of the potentiometer is large, rheostat is less.byS.V.Vijayaraj
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Traction System
What do you mean by traction system, What type of traction system is used in electric train.
anindam_07
- Jul 20th, 2008
the electric traction system is the sysatem by which traction motor is moved with loads.now a days ac 25kv,50hz.1-ph system is universaly adopted for traction movement.power comes from ohe equipment v...
tiwarianjanikumar
- Jul 4th, 2008
Traction systemmeans the system which provide the means of transportationtraction may be of a.c or d.c motor employes a.c & d.c motor respectivly
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Motor Frame Size
What is meaning of "Motor Frame Size"? What is use to determine the motor H.P?
ashish srivastava
- Sep 29th, 2014
This means the distance between the horizontal center axis of motor and ground.
sindhejs
- Feb 18th, 2009
For the coupling (motor to any other devices) purpose the motor frame come into picture. Its very important to match the frame size, otherwise motor may damage. To calculate the motor rating, it is required to have motor voltage rating and current rating.
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Ceiling Fan Rotation
The ceiling fan rotates in anticlockwise direction, Why?
pinkugkc
- Dec 16th, 2008
Motor always rotate in anticlockwise?direction?but motor shaft rotates both side?we use as a?clockwise direction or anticlock wise direction.
vijayasankarj
- Sep 9th, 2008
This is basically depends upon the angle of the blades, there is no specified reasson for that, if we change the direction without changing the angle then the air will be sucked inside.
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LPF and AC Wattmeter
What is the constructional diffrence between LPF wattmeter and ordinary AC wattmeter?
jaydeepmodi
- Dec 18th, 2008
Power is the quantity which depends on the product of current and voltage and if any-one of them is -ve then power will be -ve but if both are -ve then Power will be +ve.
jaydeepmodi
- Dec 18th, 2008
An ordinary wattmeter cant be used for the ckt which has low power factor but with some modifications it can be used and this modified form is known as LPF wattmeter.. In this wattmeter there is one c...
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Generator Breakdown
What are the major causes of a generator breakdown?
Nwannaa
- Jan 22nd, 2009
A generator is made of the drive and the driven. The drive is the engine and the driven is the alternator. Breakdown can be from the engine or the alternator.If the engine is weak due to worn out ring...
naveen.rangu
- Nov 28th, 2008
These are the following reasons for failure of Generator:1) Failure in prime mover2) Failure in field windingThe above reasons are the basic requirements for to run Generator Major Problems due to:...
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DC Circuit in AC MCB
Does using a AC MCB in a DC circuit affect the tripping time or the perfromance?
bittu123
- Nov 9th, 2011
No, it wont affect, since MCB works on heating effect.
It will get heat-up at same time, whether its DC or AC does not mattersaisln
- Dec 14th, 2008
Yes defenitly affect the tripping perfomence of MCB (AC) because DC has uni directional flow , the contact area of the contacts in DC MCBs is in higher ratings. There are chances of welding of contacts may also happened in some occasitions.
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Brush Alternator
What is a brush alternator?What is a brushless alternator?What is the difference between brush and brushless alternator?Which is better between brush and brushless alternator?
saisln
- Dec 14th, 2008
Compared to brush alternator, brushless alternator?is? best because voltage difference in the stator due improper?brush contact in slip-ring units cause more unbalance during loading of generator.
saisln
- Dec 14th, 2008
Brushless Alternator: In brushless alternator armature winding as a stator and field winding as a rotor. by this arrangement slip rings are not required to collect induced voltage because the armature part is?a stationary one.
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Purpose of Earthing
What purpose does an earth serve on a generator terminals if the generator was started accidentally.This a true incident when the generator was started it blew the earth wire because the terminals were shorted and then earthed to ground. What is the point of earthing if it cannot save the generator or the personnel.
nrathi.thb
- Dec 23rd, 2009
The earthing wire was not of proper size to bear the fault current & may be also the earthing was not done as per specification.
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Power Factor
Why the Voltage rises when Leading Power Factor is occurs?
shobhit bansal
- Apr 3rd, 2009
When there is a case of leading power factor, that means synchronous generator works in over excitation mode, reactive power will be generated, and as we know that change in voltage is directly prop...
SURAJTHEGREAT
- Mar 18th, 2009
We know flux is 90 degree ahead of voltage...If leading p.f. load is connected,the armature flux and main flux aid each other,Bcoz current(field current=flux)is 90 degree ahead of voltage. (Thus 2 fluxes aid each other)and since voltage propotional to flux,voltage increases..
Electrical Engineering Interview Questions
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