Monday, April 7, 2014

MCB Tripping Characteristics and applications of MCB'S

There are lot of MCB's available in the market. We can select the same according to load application.

MCB's Characteristics are discussed in detail below. You may easily select the MCB depending upon load.

‘B’ Curve: 
These type of MCB’S Short circuit release is set at 3-5 Rated current these type of MCB’S are used for protection of electrical circuits with equipment that does not cause surge current i.e. these type of MCB’S can be used for lighting and distribution circuits.

‘C’ Curve:
 These type of MCB’S Short circuit release is set at 5-10 Rated current these type of MCB’S are used  for protection of electrical circuits with equipment that causes surge current i.e. these type of MCB’S can be used for Inductive and Motor circuit loads.

‘D’ Curve: 
These type of MCB’S Short circuit release is set at 10-20 Rated current these type of MCB’S are used  for protection of electrical circuits with equipment that are having High inrush current . That Type of MCB’s can be used for Welding set Transformers, X-Ray Machines, Capacitor banks etc.

 ‘K’ Curve:
These types of MCB’S are Suitable for applications where high levels of inrush current are expected. 
These type of MCB’s used of loads which have Instantaneous trip is 8 - 12 In.
Theses have high magnetic trip point and are ideal for motors and transformers.
The narrow range (compared with the type D curve) makes it ideal for applications where nuisance tripping is not an issue.

‘Z’ Curve:

These type MCB’S have instantaneous trip at 2-3 In and are Suitable for applications where semiconductors and other components that fail open are used.
The short thermal delay and low magnetic trip point are ideal for applications where devices and components have low surge and short circuit tolerances.

‘S’ Curve:

These are suitable for applications with highly inductive loads
These type of MCB’S are especially used in control circuits with coils and light filaments.
 Instantaneous response between (13 - 17) In.