What is polarisation index value?.(pi value)
Simple & brief definition of polarisation index?..
- 7 Answers
- 17130 Views
- I also Faced
- E-Mail Answers
Answer Posted / v.senthilkumar - skpcl
The ratio between IR value for 10 minutes to 1 minute.
Formula (PI) = Resistance Value 10 Min after
start/Resistance value 1 Min after start. (IR 10min / IR
1min)
The recommended minimum values for PI are based on the
thermal class of the insulating materials and apply to all
insulating materials regardless of application per IEC
60085-01:1984. The PI test is not applicable to non-
insulated field winding. The recommended minimum value for
PI are as follows:
Class A Termal Class Rating = Min PI is 1.5
Class B Termal Class Rating = Min PI is 2.0
Class F Termal Class Rating = Min PI is 2.0
Class F Termal Class Rating = Min PI is 2.0
| Is This Answer Correct ? | 8 Yes | 2 No |
Post New Answer View All Answers
how to calculate differential current when we testing differential relay..suppose we have 1000kw generator,630amp VCB,what value we should put /inject so that relay trip the VCB? PLLZ justify ur comment
ratings of lightning arrester
What should be current in the Primary and secondary side of 1000KVA (11KV Supply)Transformer.?
Is single load(eg: three phase motor) having all the components like positive,negative,zero sequence components during fault condition?
What is the difference between shortcircuit current, rated current of cable & MCB with example? What will be the size of cable required for 5.5 KW motor (Full load current 10 Amps approx.), Starting current with DOL is 120 Amps. Aprrox. Short circuit current with LLLG fault is 2000 Amps Approx.
What is a slack bus?
How we can calculate the Amps for the cable Ex:- For 1sqmm wire how many amps we can draw (calculation)
Why reactive power is needed in a power system? How is it being absorbed or delivered by alternators? For reactive power control we are changing excitation but reactive power absorbing or delivering related to stator. How these two are interlinked? i want a detailed explanation with necessary expressions and figures?
What are the advantages of stationary armature and rotating field system?
What is meant by full pitched winding?
How to calculate loses in transformer of 160 KVA ?
What happens when ac supply is given as excitation voltage instead of dc supply
i wasted one year for the job after completed my btech what can i say about 1year time in interview
Define filter?
if an insulated power and control cables of a running gas diesel gensets laid direct in an open trench i.e, trench bed is not rcc of a power house in which rain water, spillage water alwas exists and all power control cables remains submerged even when gas gensets of 480 kw each runningin on load. These power &control cables runs from power house to switchgear room through these trenches in which water remains most of the time. pl explain its merit & de-merit
