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Product description
3.3 Configuration
3VL molded-case circuit breakers
20
System Manual, 03/2009, 110 0110 - 02 DS 01
VL160 to VL630 circuit breakers
The arrangement of current paths, contact configuration and switch mechanism of the VL160
to VL630 circuit breakers corresponds to that of the VL160X circuit breaker. The designs
diverge with regard to the overcurrent trip unit.
●
The overcurrent trip units are available in a thermomagnetic version and in an electronic
version.
●
The overcurrent trip units can be installed or replaced on-site without special tools.
●
Thermomagnetic overcurrent trip units are available with adjustable overload releases
and short-circuit releases.
VL800 bis VL1600 circuit breakers
The arrangement of the current paths and switch mechanisms is identical to that of the
VL160X to VL630 circuit breakers.
However, the VL800 to VL1600 circuit breakers are only available in the version with
electronic overcurrent trip unit. As with all electronic overcurrent trip units for the SENTRON
VL circuit breakers from Siemens, the current transformers (one per phase) are
accommodated within the overcurrent trip unit housing. They transmit a signal proportional to
the load current to the electronic trip unit.
All SENTRON VL circuit breakers with electronic trip units measure the actual effective
current. This method is the most accurate way of measuring currents in electrical distribution
systems with extremely high harmonics.
3.3.3
Thermomagnetic overcurrent trip units
Thermomagnetic overcurrent trip units
A thermomagnetic overcurrent trip unit consists of two components - a thermal release for
protecting against overload, and a magnetic release for protecting against short-circuit. Both
trip unit components are switched in series.
The thermal trip unit
consists of a temperature-dependent bimetal that heats up as a result of the flow of current.
This means the release is current-dependent. The heating of the bimetal strip depends on
the ambient temperature of the circuit breaker. All current values specified for 3VL for
thermomagnetic trip units refer to an ambient temperature of 40°C. Where ambient
temperatures deviate from this, the values in the tables in Chapter Derating factors
(Page 159) are to be used.
Summary of Contents for SENTRON 3VL series
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Page 10: ...Table of contents 3VL molded case circuit breakers 10 System Manual 03 2009 110 0110 02 DS 01 ...
Page 350: ...Correction sheet 3VL molded case circuit breakers 350 System Manual 03 2009 110 0110 02 DS 01 ...
Page 358: ...Glossary 3VL molded case circuit breakers 358 System Manual 03 2009 110 0110 02 DS 01 ...
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