Answer / lallan chodu

there are many ratings of a cb.making capacity breaking capacity and the list goes on which one do u need

Answer / natha

International Standard IEC 60898-1 and European Standard EN 60898-1 define the rated current In of a circuit breaker for low voltage distribution applications as the current that the breaker is designed to carry continuously (at an ambient air temperature of 30 °C). The commonly-available preferred values for the rated current are 6 A, 10 A, 13 A, 16 A, 20 A, 25 A, 32 A, 40 A, 50 A, 63 A, 80 A and 100 A[3] (Renard series, slightly modified to include current limit of British BS 1363 sockets). The circuit breaker is labeled with the rated current in amperes, but without the unit symbol "A". Instead, the ampere figure is preceded by a letter "B", "C" or "D" that indicates the instantaneous tripping current, that is the minimum value of current that causes the circuit-breaker to trip without intentional time delay (i.e., in less than 100 ms), expressed in terms of In:
Type Instantaneous tripping current
B above 3 In up to and including 5 In
C above 5 In up to and including 10 In
D above 10 In up to and including 20 In
K above 8 In up to and including 12 In
For the protection of loads that cause frequent short duration (approximately 400 ms to 2 s) current peaks in normal operation.
Z above 2 In up to and including 3 In for periods in the order of tens of seconds.
For the protection of loads such as semiconductor devices or measuring circuits using current transformers.

Is it possible that Generator trip but Turbine not trip.Give explanation.

1 Answers   Essar,

---

wat s the difference between diode and capacitor

20 Answers   TCS,

---

Since phi is the angular displacement between V & I, then why we use phi in power triangle ie. when showing active, reactive & apperent power in triangular manner & if it is ok then where is V & I in the triangle.

1 Answers  

---

What we change frequency from transformer. yes or no

3 Answers   Intas,

---

Hi, I'm running plastic reprocessing company where all motors are running only in delta. Due to that when I use start my 30 hp motor my transformer gets fuse. Where it happens two times a day. I gt a suggestion from a person about Automatic Power Factor Controller APFC. Is it useful for my problem??? Or is der any other way for solving this problem?? Upgrading the transformer is difficult. Pls give Me ur suggestion. Waiting for ur reply.

2 Answers   Shree Lingaa Polymer,

---

---

what is the differance beetwen installation and errection ?

1 Answers  

---

which technique servo motor tested o.k or faulty ?

1 Answers   ABB,

---

What is Engine?

6 Answers   HSL,

---

why our indian system choose the 230 volt for single phase&415 for 3-phase voltage,in forign side 110 volt is used what is the difference

4 Answers   Jindal,

---

What is value of earth resistance required for substation and equipment earthing and what are the reference guidelines

0 Answers   Glenmark,

---

Explain the purpose of inductor in an electric circuit?

0 Answers  

---

what is the different between surgearrester and lighting arrester

4 Answers   HPCL,

---