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What is slip power and slip recovery ?
guthajimmy
- May 3rd, 2011
SLIP-POWER: A PART OF THE AIR-GAP POWER WHICH IS NOT CONVERTED INTO MECHANICAL POWER IS CALLED SLIP POWER. IT IS REPRESENTED BY sPg. &n...
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How to run three phase induction motor as a generator
Abushama
- May 29th, 2011
Since the induction motor and Generator have the same constructor then running a motor as a generator is possible . if we want to run ?induction motor as a generator two things should be done , First...
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Ferroresonant transformer
What is a ferroresonant transformer and what is its working principle?
Nishant Choudhary
- Jun 3rd, 2011
Ferroresonant transformer are constant voltage transformer they maintain the output power to constant for any variation in input
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Relay setting details
How to set the various setting value of a relay depend upon the electrical motors ?
Nishant Choudhary
- Jun 3rd, 2011
Its very simple first note the current rating of the motor on the name plate then adjust the current setting just above the name plate motor of the motor
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Explain how direct current is produced in single-loop d.c. generator?
Nishant Choudhary
- Jun 3rd, 2011
The current produced in the armature is ac current but the commutator segment and the brushes acts as mechanical rectifier which converts ac voltage to dc voltage
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Power Generation
What measures will take for cost saving in utility and power generation
bittu123
- Nov 9th, 2011
POWER GENERATION 1. Try to increase "Diversity factor" as much as u can. 2. Try to increase "Load factor" 3. Try to decrease "Maximum demand" UTILITY : 1. Use Power factor improvement instrument lik...
Nishant Choudhary
- Jun 3rd, 2011
The first thing always be remembered that for economical purpose the power factor should always be kept around unity or close to unity this u can do by avoiding light loads or by using APFC panels to improve power factor
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What should be power angle for 11KV AC generation ?
For 600 MW Generation Purpose.
raviiisc
- Jun 9th, 2011
It will be 30 to 45 degrees.We wont allow the generator to operate at its maximum power transfer such as 90 degrees.At this the reactive power supplied by generator is the leading reactivepower. But w...
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Large Size Synchronous Machines
Why almost all large size synchronous machines are constructed with rotating field system type?
Rhombus
- Jun 11th, 2011
All the large size synchronous machines have rotating field winding because in the other case where armature is rotating we require four slip rings.. but in case of rotating field we can do with only..2 slip rings..!! :):)
veerateja
- Jul 11th, 2010
Large size synchronous machines or Alternators have rotating field winding on rotor for many reasons of them the important reasons are:- 1. The rotor can rotate at very high speeds. 2. The voltage reg...
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How torque is developed in motor ?
raviiisc
- Jun 9th, 2011
It is due to the interaction of one flux and one current.For example in Motor (induction motor 3-phase), the stator flux interacts with the rotor current leads to torque development.Somebody also says...
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On what basis is the power rating of the generator decided??
bittu123
- Nov 9th, 2011
The core criteria for deciding rating of machine is LOSSES. while this may ultimately justify all the reason specified by above person. Because temperature rise of machine depend on losses. Insulatio...
raviiisc
- Jun 9th, 2011
For any electrical equipment the power rating is decided by the thermal rating.orThe temperature withstanding capability of the machine.For generator the power rating depends on temperature, volume of rotor.
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Power Factor
What do you mean power factor?What is the use of Power Factor?
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rahulr30- Member Since May-2008 | May 30th, 2008
Power factor is the ratio of Active ppwer to apparent power in sysytem,It is an index to see how much of the energy is actually being utilized to do useful work
veerateja
- Jun 11th, 2011
pf is the co-sine of phase angle b/w voltage and current.Generalley it is leading or lagging depanding on the load whether it is inductive(lag) or capactive(lead).Take voltage as reference the current...
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At what condition a synchronous motor acts as a synchronous condenser?
arun uday rana
- Aug 8th, 2008
A synchronous motor act as a synch. Condenser when the its field winding is overexcited and there is no load attached with it. The basic application of this phenomenon can be seen in the hydro power p...
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In a synchronous motor armature current flows due to revolving flux which in turn rotates the load,but in no load condition armature current is zero hence thr is no revolving flux then how motor rotates? pls give books referance.
saginala13
- Jun 19th, 2010
Synchronous motor: we will give dc supply to the armature as a excitation, which causes revolving flux, so that motor will rotate at synchronous speed.if there is no excitation and the armature coils ...
GeeK_Percy
- Oct 4th, 2009
Armature winding is 3 phase winding and is supplied with 3 phase supplyField is supplied with DC supplied First motor is run at syn speed to lock rotor in syn speed now load is applied Questioner is confused actually the rotating field is produced by armature not by field.
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What are the technical reasons for soaking transformers for various times before allowing them to pick load after a fault or maintenance outage or as a new installation.
niceashwin79
- Dec 21st, 2010
I believe it is not soaked in water but is soaked in oil.It kept for some time because to remove all moisture and air if any trapped in insulating material and windings.
SAMIR K CHATTERJE
- Nov 17th, 2007
To improve IR value of the transformer so that it would have higher dielectric strength indeed.
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What is meaning by the SKIN effect in electrical circuits
veerateja
- Jun 2nd, 2011
In ac electrical circuits due to varying magnetic fields they induce eddy inside the center of conductor .Due to the induced eddy currents they restrict the current flow on the center and pushes the c...
ravs42
- Aug 8th, 2010
When alternating current flows thru the conductor, magnetic field intensity in the inner side is more, as a result flux concentrated on the inner conductor is very high. Since inductance of the coil i...
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Current Transformer
Explain why the secondary terminal of current transformer should not be lift open circuited.
ravs42
- Aug 21st, 2010
Due to high ratio,if the secondary is left open a very large voltage will be developed at the secondary.As a result the core vl be saturated n operator working nearby vl face severe accidents.
deepanshu_jadon
- Mar 10th, 2010
In CT secondary side is not open because it has large voltage difference
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Change in Frequency
Why do we maintain 50hz frequency? What happens when we change this frequency to any other value?
maxandrean
- Jul 5th, 2010
AC Electrical Network need to have a syncron phase for them to work. Any differences in term of frequency will shift out this syncronisation and lead the whole system to fail.
sankar_jkpm
- Feb 3rd, 2010
In our India, all the electrical power generation is based on 50 Hz. (50 cycles per second) with respect to the production of flux in alternator. So the electrical utility products are designed f...
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Measure Earth Resistance
How earth resistance is measured? What should be its value?
soulzangel
- Oct 4th, 2010
Earth resisitance can be measured using megger or earth tester and thr resisitance of proper earthing must always be less than 10 ohms and for sensitive installations such as very sensitive communication and computer systems about 2 ohms is recommended.
veerateja
- Jul 9th, 2010
Earth resistance is measured by means of earth tester or megger. The earth resistance must and should be less than 0 to 5 ohms. If it is above the 5 ohms we say earth resistance is not good.
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How do you detect the exact location of a cable fault if its cable puncture
suresharon
- Dec 27th, 2008
If it is a buried HT cable, you can avail the use of HT Cable fault locator which inject hi volt pulse into the cable and a person with an instrument can identify the exact location of the cable joint...
ramesh
- Jul 26th, 2007
You can find the fault by using murray loop test or wheatstone bridge test.
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