Section 8 -Circuit Breaker Automatic Tr Ipping System; General - Eaton DS-206S series Instructions Manual

Instructions for Low Voltage Power
Circuit Breakers Types DS and DSL
Section 8 - Circuit Breaker Automatic Tripping System

8.0 GENERAL

The circuit breaker is tripped on overload and short circuit
conditions by combined action of three components:
1. The sensors which determine the current level;
2. The Amptector solid-state trip unit which provides a
tripping signal when pre-determined current levels
are reached; and
3. The Actuator which actually trips the circuit breaker.
Schematically this may be represented as shown in Fig-
ure 59. This provides a very flexible system covering a
wide range of tripping characteristics. Not only is the
Fig. 59 Schematic Illustration of Tripping System.
Instruction Booklet IB 33-790-1J
Amptector trip unit adjustable but the sensors are avail-
able over a wide range of current ratings.
The automatic overload and short circuit tripping charac-
teristics for a specific breaker rating, as determined by
the sensor rating, are determined by the settings of the
Amptector solid-state trip unit. This unit also supplies a
pulse of tripping current to the actuator. Thus all tripping
functions are performed by secondary control circuitry,
with no mechanical or direct magnetic action between the
primary current and the mechanical tripping parts of the
breaker.
The Amptector solid-state trip units are available in two
basic versions; the Amptector II-A and the Amptector I-A.
EaToN CorPoraTIoN www.eaton.com
Effective November 2010
55