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Conductor Size of Fuse and Cable
For 63A load we can use 25/35sqmm cable. For same rating fuse conductor size is too low. How is it possible?(Its not depends on meterial, because single strand for above cable size is enough for fuse)
haveasafeday
- Mar 24th, 2009
Generally Fuse is used for short circuit protection. That means it should be higher(normally 2 to 3 times of rated current depending on design) than other installation in a perticular circuit.
sindhejs
- Feb 16th, 2009
As we know that fuse use for the safety purpose. And current will flow on the bases of resistance, as fuse?wire of small length (so it has lesser resistance), it can withstand 63A (as 25/35sq. mm cab...
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Voltmeter Measurement
If we connect a voltmeter between earth and ground wire, how much it will measure?
bittu123
- Nov 9th, 2011
there is no difference bet earth wire and ground wire, both are same thing. BUT, if U mean earth as soil (i will refer soil as earth), and U disconnected ground wire from soil and put a voltmeter in ...
p2atik
- May 16th, 2009
Since the earth and ground wires are at same potential there will be no potential displayed in the voltmeter,But on the contrary volts?may be displayed between the?NEUTRAL and the ground/earth wire.
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BusBar
What is a busbar?
manojprabu
- Mar 22nd, 2009
Busbar is nothing but just a cable in which two or more alternator or transformer are connected after synchronising them as single cable foe connecting to load
Nwannaa
- Jan 22nd, 2009
A busbar is the metal bars of copper or alluminum depending on design that are installed in panels. The bars are dimensioned according to stipulated current carring capacity and installation type.The ...
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Wattmeter
Wattmeter has two coils in it-the current coil & pressure coil, why is the pressure coil so named? How is the power being measured by the Wattmeter?
mallick.subratkumar
- Mar 21st, 2009
Current coil means it measure current of circuit & pressure coil means it measure voltage, when current coil is connected series, pressure coil connected parallel in one circuit ,as P=V*I*cos?,
So we have V, I, & ?=[1/tan(V/I)],
Now the power is being measured. -
Synchronous Generator
How and when synchronous generator acts as a synchronous condenser?
mallick.subratkumar
- Mar 20th, 2009
When synchronous generator is over exited by connecting an induction motor parallel to it, the generator gives a leading power factor which act as asynchrous condenser, it used where most of load are pure inductive (like motor).
vishweswarrao
- Mar 11th, 2009
Whenever synchronous motor is operating under over excitation it acts as synchronous condensor. This mode of operations are used for improving power factor.
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Tripper Drops
Consider you have a tripper at your house. The instant you switch on your motor, the tripper drops. What could be the problem?
mallick.subratkumar
- Mar 20th, 2009
The tripper drops because the motor is an pure inductive load & when we switch ON it, as the properties of inductive load define it oppose sudden change in current so the tripper drops when motor switch is ON.
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What is a DSM(Demand Side Management)?.
engineerfaisal
- Mar 20th, 2009
Demand-side management (DSM) programs consist of the planning, implementing, and monitoring activities of electric utilities that are designed to encourage consumers to modify their level and pattern of electricity usage.
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Current Transmission
Why is alternating current used for transmission?
bonanova
- Mar 6th, 2009
To reduce I-squared x R loss, transmission is done at voltages much higher than what is usable by consumers. Transformers can easily raise AC voltage for transmission and then lower it for consumption. The same cannot be done for DC power.
Nwannaa
- Jan 22nd, 2009
Alternating current is used for transmission because it is easier to transmit AC over high distance at high Voltage levels.It is also more flexible to handle AC at different levels of transformation t...
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Wattmeter reading
Why does wattmeter's reading go negative?
bittu123
- Nov 9th, 2011
Suppose, phase difference between V and I is "A"(angle). and wattmeter reads +ve. Now if phase difference became (A+180), wattmeter will read -ve of same magnitude.
It simply means, direction of power flow gets changed just because of changing in direction of either current or voltageSURAJTHEGREAT
- Mar 3rd, 2009
If you have seen the wattmeter ratings, it will be (300V,10A,UPF) (Voltage, Current, Power Factor) That is wattmeter needs voltage and current to measure power. So a wattmeter consists of t...
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PID control
Give brief detail on PID Control.
SURAJTHEGREAT
- Mar 3rd, 2009
A controller is a device employed to obtain a stable output. There are many controllers of that PID controller is the most widely used. A proportionalintegralderivative controller (PID...
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Magnets in Speaker
Why magnets are used in audio speaker?
SURAJTHEGREAT
- Mar 3rd, 2009
We know audio signals are going be as signals (ac signals are those whose amplitudes are constantly changing). The speaker system employs 2 magnets. 1-Electromagnet, 2-Permanant Magnet. When 2 mag...
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Neutral Earthing
What is neutral earthing and equipment earthing?What are the advantages of grounding a neutral of a transformer and gernator?
SURAJTHEGREAT
- Mar 3rd, 2009
Nuetral point is useful. Bcoz the extra current flows to the ground. Ground is always at a higher polarity than the device. For example consider your instant heater. It always is a 3 pin plug point....
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Vector Quantity
Is current a Vector quantity? If yes, then two wires on 90 degree angle must have resulting current equal to zero.
SURAJTHEGREAT
- Mar 3rd, 2009
According to me, current is neither scalar nor vector completely. It does not obey, vector law of addition. We know kirchoff's law, Current leaving = current entering. So if load is connected at the...
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Units Calculation
How many units will a 40W tube consume in 1hr 15 minutes 20 seconds?
SURAJTHEGREAT
- Mar 2nd, 2009
1 unit=1000 watts.Therefore 40 watts=0.04 units.(40/1000)If the light consumes 0.04 units for 1 hour.then for 15 min it is (0.04/4)=0.01 unitsI calculated this way(1 hr=4*15 min...Then for 15 min(divi...
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Transformer Shutdown and Trip
What is the differance between shutdown and trip?
sindhejs
- Feb 18th, 2009
Purposely making the transformer stop(down) is the shutdown,for the purpose of maitainance etc.Unevenly stop the transformer due to any faults; is the Trip.
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Busduct & Rising Main
Explain what are busduct and rising main? Where it is used?
sindhejs
- Feb 16th, 2009
Bus ducts are the mechanical protection to the bus bars, may be rectangular or square hollow boxs.
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Skin Effect
What do you mean by skin effect?
sindhejs
- Feb 16th, 2009
Tendency to concentrate the electrons towards the outer surface of the conductor is the Skin effect. It can be avoided by small dimension cables instead of large dimension.
vinod25988
- Dec 1st, 2008
As the answers given are correct. It is a loss if the diameter of the conductor is large.So skin effect have to be prevented
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Test New Electrical Installation
In residential building electrical installation has been completed. How will you test this new electrical installation of building?
Electrical Engineering Interview Questions
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