-
Delta and Star Connected Capacitor Bank
Why do we use delta connected capacitor bank in a self excited induction generators and not star connected capacitor bank?
-
What is the name of sound when we start the D.G.Sets
-
T/F Differential Protection
Can differential protection operate while its only one side is energized or being energized (HT side in this case)? When trying to energize a 132/11KV t/f from HT side when its differential protection operated while its LT side breaker was still open? Was it because of starting inrush current or t/f tap position?(It has an auto tap changer on HT side & while it was being energized tap position was...
pashwuee
- Apr 2nd, 2010
Transformer tripped due to inrush not because of tap changerNumerical relays take care of harmonics during inrush current so transformer does not trips.If it is tripping setting needs to be checked
-
Motor
What is the testing of h.t and l.t. motors before erection and commissioning?
Raman Jain
- Sep 28th, 2008
Mainly IR value has been taken at site.Proper alignment has to be checked.No load run for 6 hours for temp. rise .
-
Fuse Rating
Dear AllI wan to know that we are using large type of cable like 300sqmm and other and our load also in much kw but we are using a small type fuse in main supply (not HT Side) how can it bear load.
Abhijit_atrangi
- Aug 7th, 2008
Fuse rating and cabel selection is depend upon the load current and fuse current is always greater than the load current. Suppose? your load is motor then the starting current of motor is 3 times gre...
-
DC Machine as Generator
It is possible to run one DC machine as a generator or motor purposely? What adjustment we have to do for that operation?
arun uday rana
- Aug 1st, 2008
We can operate a electromechanical energy conversion device as generator as well as motor. It depends how we want to operate the machine. A machine works as an motor when we provide electrical energy ...
-
Indian Standard Generation
Why Indian Standard Generation voltage is 11kv?
rrajput
- Aug 10th, 2008
The form factor of ac sine wave is 1.1107 so the generation of ac is to be done in multiple of 1.11 and hence 11 is chosen as an standard.
-
PLC
What is PLC? Outline its working Principal.
upendra.sachan1
- Sep 1st, 2008
Generly PLC is stand for programming logic control. Its principle based on switching theory of GATE and conditional circuit. It is widely used in every type of industry for the controlling of everything and this procees is called automation.
-
D.C Motor Rheostat
If the position of rheostat is changed from minimum position to maximum position in D.C shunt motors speed is increased, how?
Abhijit_atrangi
- Aug 19th, 2008
In D.C shunt machine by inserting the rheostat in the field we can increase the speed above the base speed in the ratio 3:1 but above that machine get overheated. When we increase the resistance field...
-
Transmission Line
What is Transmission Line? How it is used? Give examples.
Abhijit_atrangi
- Aug 19th, 2008
Line which is used to trasmit the high voltage or high power is called transmission line, high voltage E.g. 220kv, 132kv, 66kv etc. all this voltage are of transmission voltage range. Example of transmission line is : D.C line of +/- 800kv from Chandrapur to Padage in India
-
Syncronous Generator Flying Off
One advantage of syncronous generator is that there is no possibility of armature conductors flying off. What do you mean by flying off?
-
High Rating Motor
Why soft starter is provided for higher rating motor?
luvvictor
- Aug 29th, 2008
For a high rating motor the torque is very high. We require a high starting curent in the very begining to develop this torque, so the starter is kept soft so that it does not make the motor off for increasing value of current but the process is done upto?a certain limit of current.
-
Series Shunt Motor
Can we recognise if motor is series or shunt by visual inspection? If yes how?
Abhijit_atrangi
- Sep 1st, 2008
Yes, we can in the lab, theire is a winding denotes on the machine panel where it is the series or shunt motor, where series motor having less no. of turns of field in seies with armature and shunt has more no. of turns of field in shunt with armature.
-
Pure Sine Wave Inverter
What are the applications of pure sine wave inverter?
engineerfaisal
- Apr 13th, 2009
Pure Sine Wave Inverters will: Allow inductive loads like microwave oven and motor driven products to run faster, quieter and cooler. Reduce or eliminate audible and electrical noise in fans, flo...
-
Electrical Transducer
What is the fuction of electrical current transducer, voltage transducer in control panel?
Raman Jain
- Oct 22nd, 2008
Tranducers are used to convert Electrcal Quantities to standard signal of 4-20mA or 0-10 V etc. The main advantage of using them that possibility of opening of CT when changing ammeters , damage(burnt...
-
PNPN Thyristor
Why PNPN is used as thyristor NPNP is not used?
bittu123
- Nov 8th, 2011
Funny, what differences PNPN & NPNP makes? If you have PNPN thyristor, its kept on table, U are seeing PNPN, right? Now, keep its back in front, whats this now? NPNP......isn't that? its not transist...
-
Current Carrying Capacity
What is the current carrying capacity of Moose conductor? What are the factors detrmine the current carrying capacity of any conductor?
ramakrishnan1951
- Nov 29th, 2008
APPROX. CURRENT
APPROX. CURRENT IN AMPS AT 40?C AMBIENT OVER THE TEMP. RISE OF
IN AMPS AT 40?C AMBIENT OVER THE RISE OF 40?C 45?C 960Amps 1000Amps -
Sine Wave
Why we use sine wave in supply system rather than square and triangular wave?
-
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
-
Motor starters
When is star-delta, Dol or VFD starters used for the motor? How many times the current rating of the motor wil be drawn on a Dol starter if no OLR used?
ibicelectrical
- Oct 31st, 2008
If there is a load like conveyor belt, chain drive, etc. then there is considerable time required by the motor to start and come to required load, so there is large current requirement at the tim...
Electrical Engineering Interview Questions
Ans