Circuit breakers provide intelligent protection

An ABB Automation Tech (LV Products) product story

Edited by the Engineeringtalk editorial team Apr 6, 2005

The Emax range of air circuit breakers provides protection, network analysis and communications for virtually any electrical application with rated uninterrupted currents from 800 up to 6300A.

A new range of air circuit breakers with improved electrical performance has been launched by ABB.

The Emax range provides protection, network analysis and communications for virtually any electrical application with rated uninterrupted currents from 800 up to 6300A.

The range is available in five frame sises (E1,E2,E3,E4 and E6) with breaking capacities up to 150kA at 415V in fixed and withdrawable versions.

At the heart of the Emax's improved performance are three re-engineered protection releases (PR121, PR122 and PR123).

The current sensors within the protection release have been updated to incorporate a high level Rogowsky coil.

The Rogowsky coil provides the circuit breaker with a linear response over its entire range of currents thus providing faster responses times.

The in-built CT, on the other hand, has been optimised to power the trip alone and reduce the energy transmitted to the trip at high current levels.

A combination of these two features means improved performances for the circuit breaker are possible.

For instance, the Emax E1 model now offers current ratings up to 1600A (previously 1250A) and the E2 model is enhanced with a version S that offers a breaking capacity of 85kA at 440V.

The new trip units include additional protection functions such as: residual current protection up to 3200A; "double S" protection used to obtain discrimination in critical conditions; "double G" protection to differentiate between restricted and unrestricted earth faults; and even complete double settings allowing transfer from one set of protection parameters to another.

ABB has incorporated protection features into the Emax range that are normally supplied by external relays.

Features such as directional and reverse power protection, restricted earth fault and metering including harmonics information are now included within the circuit breaker.

This means that panelbuilders no longer need to add additional CTs or external wiring to accommodate these features within switchboards.

In this way, they can reduce their labour costs as well as reduce the size of their switchboards.

The Emax range of ACBs is the first on the market to include protection units incorporating a datalogger function that allows users to get a full picture of what happens during a trip event.

The information stored in the trip unit allows users to carry out comprehensive fault analysis including what happened before, during and after the trip.

The inclusion of a high-definition low power consuming graphic display means the data is easier to read.

Responding to customer demands for greater access to trip information more quickly and remotely, ABB has added a wireless communication module to the Emax range based on Bluetooth technology.

This enables users to connect to and communicate with the circuit breaker via a PDA or laptop from up to 10m away and without the constraints of wiring.

The addition of a communication module also means Emax can be connected to any major fieldbus network (when combined with ABB's fieldbus plug), allowing the remote supervision and control of the circuit breaker.

It is also possible to control and monitor devices outside the circuit breaker with the addition of new external input/output modules.

The metal housing for the protection releases has been replaced with polycarbonate making it recyclable and 70% lighter.

The protection releases are also easier to install thanks to the use of a modular structure that allows the external modules to be "snapped" into the housing.

Standard accessories are available for the entire range and can be used with both alternating and direct current.

Assembly of accessories is always carried out from the front of the circuit break and without any cabling required for easy installation.