MF DIGITAL 5907-VL Specifikace stáhnout pdf (Strana 20)

3WL Air Circuit Breakers

3WL Air Circuit Breakers/Non-Automatic Air Circuit Breakers up to 6300 A (AC)

General data

Siemens · 2012

Measurement method

Vectorial summation current formation (measurement method 1)

The three phase currents and the N conductor current are mea-

sured directly.

The electronic release determines the ground-fault current by

means of vectorial summation current formation for the three

phase currents and the N conductor current.

Direct measurement of the ground-fault current (measurement

method 2)

A standard current transformer with the following data is used for

measurement of the ground-fault current:

1200 A/1 A, Class 1 (the internal load of the 3WL circuit breaker

is 0.11

). The current transformer can be installed directly in the

grounded neutral point of a transformer.

3-pole circuit breakers, current transformers in the N conductor

3-pole circuit breakers, current transformers in the grounded neutral

point of the transformer.

4-pole circuit breakers, current transformers in the grounded neutral

point of the transformer.

Setting

How the module is set depends on the measurement method

used (see above):

Measurement method 1: in position .

Measurement method 2: in position .

This setting can be implemented for the electronic release ver-

sion ETU76B with Menu/Comm.

Ground-fault protection with

t characteristic curve

With the exception of the ETU27B electronic release, all

versions of the ground-fault modules are supplied with an

characteristic curve which can be activated.

Selection criteria for 3WL circuit breakers

Basic criteria for selecting circuit breakers are:

• Max. short-circuit current

at place of installation of circuit

breaker

″

k max

This value determines the short-circuit breaking capacity or

short-circuit current carrying capacity of the circuit breaker.

• It is compared with the value

of the circuit breaker

and essentially determines the size of the circuit breaker.

See illustration "Overview of 3WL Circuit Breakers/Non-Auto-

matic Air Circuit Breakers".

• Rated current

which is to flow through the branch circuit.

This value must not be greater than the maximum rated circuit

breaker current of the circuit breaker.

The rated current for the 3WL circuit breaker is specified using

the rated current module. See illustration "Overview of 3WL

Circuit Breakers/Non-Automatic Air Circuit Breakers" in "De-

sign".

• Ambient temperature

for the circuit breaker.

This is usually the control cabinet internal temperature.

•Design

of the circuit breaker

• Minimum short-circuit current

which flows through the switching device. The release must

still detect this value as a short-circuit and must respond by

tripping.

Protection functions

of the circuit breaker.

These are determined by the selection of the

corresponding electronic release, see the table

"Functions of the Electronic Releases" under "Functions".

NSE 00946

SENTRON WL

NSE 00947

SENTRON WL

T6: 1200 A/1 A

NSE 00948

SENTRON WL

T6: 1200 A/1 A

1 2 ... 15 16 17 18 19 20 21 22 23 24 25 ... 61 62

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