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 |
How to select HT/MV cable size ?
How much ampere rating on LT side of distribution transformer and also on HT side of 200KVA transformer
How to calculate Busbar Thickness for Different type of HT/LT panels
what clearance required for 4.5 mva dry type transformer?
What is the meaning of 40X8X2 busbar dimensions for carring load of 400 Amps
why the admittance matrix or y bus matrix of a large network is called sparse matrix?
why cable i burning without tripping. how can protect led street lights
why transformer do not rotate?
How turns ratio test is done in three phase transformers?
why rotor winding in induction motor is not earthed. normally we uses star winding in rotor .why?
3 Answers Anglo Platinum, TATA,
What are the weight of 800KV DA,DB and DC type tower ?
WHEN TWO ALTERNATORS ARE OPERATING IN PARALLEL, EXPLAIN WHY IT IS OBJECTIONABLE TO OPERATE ONE AT A LEADING POWER FACTOR AND ONE AT THE Lagging power factor?