Answer / asif mansoori

All 3 devices are used for protection from Earth Faults.

Earth Leakage Circuit Breaker is used for putting the circuit off in case any residual current passes out of the circuit & the difference is more than the rating of leakage current, e.g. 300mA, the circuit breaker will go off or cause the main circuit breaker to trip. Usually ELCB is comprising of one main circuit breaker and leakage breaker.
Nowadays, MCB+RCCB acts as RCBO or ELCB. If you use RCCB alone, only protection from leakage current is achieved, if you use both MCB & RCCB, then you get protection from both overload, short circuit and leakage.

ELR is earth leakage relay which is available standalone relay with dry contacts for externally tripping the main circuit breaker.

ELS is also type of ELR, but this is sensor & rating of this is lesser than ELR. For smaller leakage currents, ELS is used.

ELCB-Earth Leakage Circuit Breaker
ELR- Earth Leakage Relay
ELS- Earth Leakage Sensor

What is the output of a transformer..??

1 Answers   Jindal,

---

What is milivolt dop test in Busducts? What is its significance & procedure to do the test?

0 Answers  

---

In dc motor starter there is less voltage required for holding contactor that's may why it is called no volt coil. but in ac starter why holding contactor is called no volt coil.

2 Answers   JSW,

---

We have 2 Nos. Transformer with the capacity of 2000KVA and 1250 KVA and currently using only one 2000KVA T/R during operational hours while non- operational hous 1250 KVA T/R also used to reduce T & D losses. Similarly, 2 capacitor bank of 500KVAR and 300 KVAR also installed to balance reactive power. Now problem is around 1000 KW load PF is not maintaning 0.99 as 350 KVAR capacitor is in healty condtion. Now the PF is maintain 0.95 to 0.96.

2 Answers  

---

how the ac voltage are selected like 220v,415v,750v,1000v& 1.KV,6.6KV,11KV,33KV,66KV,132KV,220KV & why these are selected like these orders

2 Answers   Jindal, JSW,

---

---

which network topology offers the greatest level of tolerance?

0 Answers  

---

Explain why the Voltage drop will happen in 3 Phase line?

2 Answers  

---

What is the safe limit of voltage between earth and neutral in india.

2 Answers   Incepta Pharmaceuticals,

---

what is the difference between a race around condition and toggling?

1 Answers  

---

What is corona? and what is the purpose of corona belt in substation ? why they connect these end of the buses ?

2 Answers  

---

In an panel board if the outgoings are power plugs and motor equipments...what should we choose as the incomer of the of the panel board?? MCCB OR ISOLATOR?? Should we use ELCB protection??if so where??

2 Answers  

---

how can we check a fully charged battery?

6 Answers   BEML, Singareni Collieries,

---