Answer / ashish

its a type of overcurrent - earth fault relay --
IDMT -- inverse definite min. time , having diff types--
normal inverse / long inverse / short inverse type

the relay are of 3 types
1) electro mechanical (whose opeartion way is described by
others)
2) static and latest are 3) numericals --no moving part.

the simple way to explain its principle is that
THE RELAY OPERATIONAL TIME IS INVERSELY PROPORTIONAL TO
THE FAULT CURRENT. IN NORMAL INV IDMT FOR A 2.0 TIMES
CURRENT WITH TMS (TIME MULTIPLIER SETTING) of 1.0 THE RELAY
OPERATInG TIME IS 10 SEC,.. WHEREAS FOR THIS SAME SETTINGS
IF CURRENT IS DOUBLED THE TIME REQUIRED IS ALMOST 5 SEC..

but after 20 amp(in 1 A relay) the time reqd is same.

Answer / ajay k mathew

Inverse Definite Minimum Time relay.aluminium or copper disc rotate b/w electromagnet and damping magnet.fluxes induce eddy currents and interact to produce torque.disc rotate to a point where it operates a pair of contact and remove fault

Answer / santhosh.9289

the current in the main winding produces magnectic field that displaced to closing winding,auminium disc produces eddy current that disc make rotate.as the current disc of rotation is high minimum time of operation

Insulater disk using formula for 33/66/135 line h t line

1 Answers   Hofincons, Kirloskar, KPTCL,

---

I need a 33/690V Dry type transformer.How to select IP class for this transformer.This will be an outdoor transformer located in a highly polluted environment.

3 Answers  

---

generally on the roadside v hav 11kv line which is being step down to 440v line to line....so any1 can tell me which type of transformer they r using whether it is star to delta,delta to star etc...???

9 Answers   Core Solutions,

---

a 120 60 watt incandescent lamp has to be operated from 50 c/sec 1 phase ac supply. in order to do this a circuit element has to be connect in series with the lamp. which one of the following sries element is preferable.

1 Answers   SSC,

---

Is there any problem ,if R-Y-B voltage is constant , but the air compressor taking one phase high current.what is possible causes.the said compressor is very new.(55kw).

4 Answers  

---

What is difference between insulating medium and fault current interruption medium in a switching device.

0 Answers  

---

Why Water motor is not taking a load or pressure while everything is correct. (Note: Motor running properly)

0 Answers  

---

what is the formula for transformer oil?

1 Answers  

---

What is the difference between Derived earth Fault and measured earth fault.How it works.

1 Answers  

---

i am gng to visa interview this july i have 4 backlogs gre 1010,toefl 75,pls give me the tips pls pls

0 Answers  

---

What do we use in Motor core laminations..???CRGO or CRNGO..and why..????

1 Answers  

---

i have total 8 dg sets for synchronizing and 2 buscoupler,1 sectoin dg no 1,2,3,and 2 sectoin dg no 4,5,6,and last section dg no 7,8 ....if buscupler no 1 and 2 is off mode ..than dg no 1,2,3,will synchroniz of another dg sets?

0 Answers   Crown Buildtech,

---