Answer / yashpal

plug setting is = 3.75 means pick up= 3.75 A.Relay
operating time will depends on the charecteristic of relay.
(invese,normal inverse).if the fault current is 8000A then
current in the sec will be 10 A which is three times of
3.75A(connected plug setting),now just watch the relay
charteristic written on relay u can get the time required
for relay operation.(ex- for inverse charecteristic relay
for 3 time current & tms = 1 ,timing is 6.25 sec,so for
our problem timing will be 6.25 * 0.15=0.9375 sec.

Answer / yvb

your PSM set for 3.75 means 3.75 times of your py.
current. if fault current is 3.75 times of 4000 i.e 3.75 x
4000 = 15000 A. your relay will operate in 0.15 sec.(
Primary Injection.)on Secondary we can say 5 x 3.75 =
18.75A flows through ur relay.
Now comming to ur case if fault current is 8000A ie. 2
times of 4000 or u can say 2 times of 5 A.
Then your relay will operate in 0.282 seconds.

how to reduce the magnetizing current in distribution transformers

1 Answers  

---

can anybody find out the result. I am lil bit confused about my equation.

1 Answers   Student,

---

Logic using 1 kV or 1,1 kV grade in house wiring Low voltage cable. Explain/suggest? some use 1kV and some prefer 1.1kV grade insulation low voltage cable why??

0 Answers  

---

what is accuracy ? in any meters , coils accuracy . how can u defined that ?

0 Answers   Adani,

---

what is real power and reactive power?

3 Answers  

---

---

What is use of starter and choke in tube light

0 Answers  

---

BRIEFELY EXPLAIN MEGGAR PRINCIPLE

2 Answers  

---

What are pre paid energy meters ? How it works ?

1 Answers   Siemens,

---

Two liquids hot and cold in two vessels are there and an metal bar acts as a conductor of heat between the two vessels. what happens then. what happens after 24 hrs?

0 Answers  

---

we done magnetic balance test for 33KV /440V transformer in our company , but the ratio out is confusing us Voltage applied in RY = 440 , at RB = 320 and YB = 60 RY 440 = ( RB + YB ) 380 only Please let me know what type of problem is it.

2 Answers  

---

what is diff between Fourier series and Fourier transform?

2 Answers  

---

State uses of different types of stsrters with different capacities of motors as below: a. up to 5HP b. above 5hp to 10hp c. above 10hp to 20hp d. above 20hp

0 Answers  

---