What is the Polarisation index value ? (pi value)and
simple definition of polarisation index ?
Answers were Sorted based on User's Feedback
Answer / shane e.
It is the ratios of of insulation resitance on a DC hi-pot test over 10 minutes. If less than 1 insulation is surely breaking down.
| Is This Answer Correct ? | 0 Yes | 1 No |
Answer / lovy
Polarization index is an indirect method of testing which may mislead about healthiness of transformer insulation
so instead of pi , capacitance and tan delta should be measured for keeping a correct check on insulation
| Is This Answer Correct ? | 13 Yes | 15 No |
Answer / josephat murusura
PI is the ratio of the 10minutes megger value to that of
the 1 minute.The minimum acceptable value is 2.Any value
below 2 is not good enough for the operation of the
electrical machine[motor or transformer]& it indicates that
the winding insulation has detoriated.
| Is This Answer Correct ? | 3 Yes | 13 No |
Answer / karthik
It's minimum acceptabce value depends on the class of
insulation also. Minimum recommended value IR(60 sec)/IR(15
sec) should be 1.3 for all classes of insulation.
| Is This Answer Correct ? | 6 Yes | 18 No |
Answer / sandipan sarkar
it is ratio of insulation resistance (IR)for 10 minutes to
insulation resistance for 1 minute.
it should be 2.5
| Is This Answer Correct ? | 35 Yes | 57 No |
Why underground cables are used to connect transformers?In addition how are they again connected to lines after step up or step down?
what is demagnetising effect & crossmagnetising effect and how it is related to electrical system?is there any more effects are available or only these two??
how to calculate fault level?
what happens if earth of 33kv cable is not connected to earthing pits? please send this query's answer to ngrm.sudha249@gmail.com
why the electric train touches only one conductor n where is the neutral n it will be running 3-phase or 1-phase?
what is the difference between PLC and embedded system
Relation between pyramids and electrical technology?
In HI POT test what is reason for applying the AC VOLTS and DC VOLTS in different applications what is the nessesity for this ?
WHAT ARE THE BELT HORMONICS IN AC MACHINE HOW TO REDUCE IT
Please give me a erda placement paper
Why magnetic flux produces an induced current?? what is the detailed procedure ?? ans plz
1.Z transform always lies around ? a) origin b) pole c) zero d) z=1. Multiples Mcqs which is bother me can’t find answers on internet. Some help required with little explanation . Note: this is not homework or related to any test. Thanks
Civil Engineering (5086)
Mechanical Engineering (4456)
Electrical Engineering (16639)
Electronics Communications (3918)
Chemical Engineering (1095)
Aeronautical Engineering (239)
Bio Engineering (96)
Metallurgy (361)
Industrial Engineering (259)
Instrumentation (3014)
Automobile Engineering (332)
Mechatronics Engineering (97)
Marine Engineering (124)
Power Plant Engineering (172)
Textile Engineering (575)
Production Engineering (25)
Satellite Systems Engineering (106)
Engineering AllOther (1379)