Answer / raghavendran

MCB's have tripping curves like B,Cand D.

Curve B type of MCB's are used where maximum sensitivity is
needed and the initial starting current is 3 to 5 times the
rated current.

curve c MCB's are used where close protection is not
required and the starting current is 5 to 10 times the rated
current.these may be used while tripping the circuit due to
high starting inrush current.

curve D MCB's are used where the starting current is very
high 10 to 20 times the rated current, like high capacity
motor installation where initial starting voltage dip may be
very high.

Answer / anil tandon

The MCBs are classified as per the Holding Currents and thus their usage are define accordingly,

B-Curve MCB:- They have a Holding current of 2 times of rated current and are used for Lighting Loads

C-Curve MCB:- They have a Holding current of 5 times of rated current and are used for motoring Loads.

The MCBs are classified as per the Holding Currents and thus their usage are define accordingly,

B-Curve MCB:- They have a Holding current of 2 times of rated current and are used for Lighting Loads

D-Curve MCB:- They have a Holding current of 10 times of rated current and are used for High Inrush currents E.g -Control Transformer etc

Answer / arshath

B curve using for domestic
C curve using for industrial

400kw, 3.3Kv motor want to fix 1000km away from substation. What is full load current? and what is the cable size for motor? I amp expecting answer and advice from your side.. thanks...

4 Answers   Kuwait Oil Company, Weatherford,

---

1.why motor rating in kw instead of KVA? 2.why alternators rating in KVA instead of KW?. 3.why transformer rating in KVA instead of KW?.

6 Answers  

---

What is EMC filter in VVVF Drive ?

0 Answers   Bengal Energy,

---

how test transfomer(3 phase75kva) by megger

0 Answers   HPL,

---

what is the differnce between high impedance relay and low impedance relay

4 Answers   Areva,

---

If the Supply voltage is increased by n times, the cross section of conducter will [increase/decrease] by ________ times ?

4 Answers  

---

transformer test

4 Answers  

---

Can you explain operating principle of Inverse Definite Minimum Time” (IDMT) relay

2 Answers  

---

what is the working principle of soft-starter & how it diff. from VFD ?????????

5 Answers   L&T,

---

What does the term power factor shows?

0 Answers  

---

how to calculate bus-bar sizes? (copper bus-bars)

2 Answers  

---

What is formula of capacitor for 1-phase power connection.how to improve PF. Suppose I want to connect capacitor in refrigerator to reduce power consumptions.

0 Answers  

---