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Explain about polarities ?
- Dec 11th, 2013
Polarization is a complex subject? But is easiest understood to me a position, location, direction, depth and etc. from a center point of refrence it is easiest understood by ceating a sphere around t...
Yasser Ali
- Nov 1st, 2013
Polarity may refer to: In science: Polarity (mutual inductance) Polarity (physics), a physical alignment of atoms Cell polarity, differences in the shape, structure, and function of cells Chemical po...
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3 phase induction motor
prove :
average power = instantaneous power
in 3 phase induction motorripplenwinder
- Dec 11th, 2013
We can define the 3-phase voltages as: 1) v1 = Vp x sin(u); 2) v2 = Vp x sin(u +120); 3) v3 = Vp x sin(u -120) 4) vn^2 = v1^2 + v2^2 +v3^2 = K 5) sin(u +/- v) = sin(u)cos(v) +/- cos(u)sin(v); 6) sin^...
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Impedance matching
Explain briefly about impedance matching and how the transformer serves in impedance matching?
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Transformer design and construction
What is shape of the coils used in a transformer ? choose the correct one from the bracket (rectangular,oval,circular,cylindrical ) & justify it with detail reason.
Is transformer a machine ?choose the correct one from the bracket (yes/no) & justify it with detail reason.
manikandan.l
- Jul 18th, 2014
Rectangular
AlHussein Abdallah
- Jul 17th, 2014
Star connected rotor of induction motor has a standstill impedance of (0.4+4j)ohm per phase and rheostat impedance per phase is (6+2j)ohm. The motor has induced voltage of 80v between slip-rings at st...
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Power System
Difference between pi and pid controller
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Path of current in domestic loads
I am confused about the path of current in domestic loads . In the negative cycle does the current flow from neutral to the phase.wont the whole system get grounded then if we use a single phase ground return?
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IES
How can I prepare for Ies from 2nd year onwards?
shailesh
- Aug 1st, 2015
By applying for IES Exam online
chandramvs
- May 29th, 2015
First of all your core subjects begin from 2nd year only.so be strong with your B.E/B.Tech subject. If you have good faculty then go on par with them and study the complete subject within the same se...
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Why star delta starter prefer to D.O.L starter for large motors?
We prefer star delta starter for reducing start voltage but Normally in D.O.L starter-motor is always connected in star - it will also start in reduced voltage.... Explain
saeed iqbal
- Jul 24th, 2015
In starting motor gets 3 to 4 times more current then its normal current. So we use star delta starter to limit the starting current of the motor with the help of star circuit.when motor will run in t...
Ahmed Elsisy
- Jul 22nd, 2015
In large motors: when motor start it draws a large current in starting , so we use star delta method to reduce this current in starting by Firstly we connect motor on Start (motor no loaded) on low v...
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Induction Motor Phase Swinging or Hunting
What is Phase Swinging or Hunting in Induction Motor?
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Measure Cross-Sectional Area of a Cable
How to measure the cross-sectional area of a cable which is 1000 sq. mm.?
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Power Electronics - Determine Resistor, Capacitor and Inductor Using a Battery, a switch and a Lamp.
you have three boxes, one has a resistor, second has a capacitor, and the third has an inductor. Find what is in each box, using a battery, a switch and a lamp. You can build any circuit you want, to figure out which box have a resistor, and which one has the inductor, etc. How can you solve that?
chandramvs
- Jan 3rd, 2016
Connect the battery, switch, lamp and the box in series and observe what happens, 1) If the lamp glows with constant brightness then the box has resistor. 2) If the lamp initially is dark and finall...
abdelmonsef
- Jan 2nd, 2016
A battery is DC, so when connecting the battery and the capacitor and the lamp in series, the lamp will not be on (as the capacitor is open circuit in DC system) and when connecting the battery and th...
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Half Controlled and Full Controlled Rectifier
What is the difference between half controlled and full controlled rectifier? Why we go for full controlled while half controlled can control voltage?
k.r.kartheeswari
- Apr 10th, 2017
In Half controlled rectifiers, the controlled output will be in one half cycle, so the efficiency is less. But in full controlled rectifies, the controlled output will be in both the half cycle since both the sides having SCRs. So efficiency also doubled compared to half controlled.
pradeep1987
- Feb 4th, 2016
Diode is uncontrolled and SCR is fully controlled element. In SCRs we can turn ON and OFF by gate pulse or by the other means. Whenever the diode is used in rectifier, the rectification is done by the...
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Input Impedance of Cascade Amplifier
The input impedance of cascade amplifier will :
a. Same as input impedance of first
b. Same as output of second.
c. Same as the entire circuit
d. Same as Stage before the last stage -
Constant Frequency Grid
Why frequency should remain constant in Grid? If it varies then what will happen to other generators?
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Harmonics Power System
What are the advantages & dis-advantages of Harmonics in Power System?
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Megger Test
Dear All,
I have a done a house hold wiring for villa, During a megger test we notice that valve between phase and neutral is good 500 Mohm when test between Phase to earth wire it is shown as less than 100 Mohm when I remove the all wire from conduit and we test it is showing correctly as 500Mohm, After that i replaced all wire as New before pulling the wire in conduit i checked it is shown... -
Strung bus
What is meant by strung bus and where is going to be used and what is purpose of it?
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Improve Power Quality
Night time load on our system street lights, one DG battery charger-24v, 6 KVA UPS. On UPS only 12v solar fencing battery. You are suffering from leading pf. Can you say how to improve pf?
Electrical Engineering Interview Questions
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