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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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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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What is induction motor?
ajayyadav07
- Dec 28th, 2008
Induction motor is motor that work on the principle of INDUCTION, when the stator winding is connected to the supply mains then there is magnitic flux generated due to the flow of current in stator wd...
tarun aggarwal ymca
- Sep 28th, 2008
Inductor Motor based on the principle of induction, in this when we apply single phase AC current field is set up as motor winding are closed current is induced in them which once moved through any method (capacitor start) cut the magnetic field and force is exerted on the motor
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Inductive Load
How to design inductive load for 3 phase 440v and maximum 5 amps for star or delta?
venky_sastra
- Dec 28th, 2008
V=I*ZV=440VI=5AZ=440/5=88Z=X*LX=2*pi*Fif f=50 HZTNEN WE CAN FIND OUT THE INDUCTANCE
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Leakage Currrent
How will you calculate the leakage current?
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Limit Short Circuit Current to Twice the Full Load Current
Full load SLip of a 400vstar connected 50 hz 3ph IM is 3.5 and with locked rotor full load current is circulated if 92v is applied between lines find the necessary tapping on the autotransformer so as to limit short circuit current to twice the full load current.
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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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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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Whats is difference between Earth and Neutral
ksubbu
- Feb 4th, 2009
Earth is provided to protect the equipments and appliances. It also protects us from shock hazards. Neutral is the return path for the current.
arun uday rana
- Jul 31st, 2008
Earthing of a system is to protect the system from high surge current/voltage due to lighening while neutral provides return path to the current flowing in the tranmission line.
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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?
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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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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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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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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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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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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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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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