Siemens 3VT MCCBs Up To 1600A

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3VT2 Molded Case Circuit Breakers up to 250 A

Overcurrent releases

3/15

Siemens LV 36 · 2008

3

■

Overview

The electronic overcurrent release consists of a separate and

interchangeable unit, which is supplied with the 3VT2 switching

unit. By exchanging the overcurrent release, the range of the

rated current of the circuit breaker can be easily changed.

Overcurrent releases for 3VT2 switching units are produced with

current values of

I

n

= 100, 160 and 250 A

. The ETU LP are pro-

duced with rated currents of 160, 200 and 250 A. The releases

(including regulation of -60%) cover a current range

from 40 to

250 A

.

Tripping characteristics

Depending upon the needs for adjusting the tripping character-

istic to the protected device and to the variability of the charac-

teristic with regard to selectivity, the following releases are avail-

able:

ETU LP

They have one type of characteristic and fixed-set

I

r

and

I

i

settings.

ETU DP

They have one type of characteristic with adjustable

I

r

and

I

i

.

ETU MP

They have more kinds of characteristics with adjustable

I

r

, t

r

and

I

i

.

ETU MPS

They have more kinds of characteristics with adjustable

I

r

, t

r

,

I

i

and t

v

.

ETU LP, DP, MPand MPs overcurrent releases are intended for

3-pole 3VT2 725-.AA36-0AA0 switching units and 4-pole 3VT2

725-.AA46-0AA0 switching units with disconnecting of the N

pole.

ETU DPN

They are intended for 4-pole 3VT2 725-AA56-0AA0 switching

units with protected N pole. They have more characteristics with

adjustable

I

r

, t

r

,

I

i

and

I

N

.

NSO0_00502

t

I

L

I

NSO0_00506

t

I

L

I

I

r

I

i

t

r

NSO0_00215

t

I

L

I

I

r

50 ms

0 ms

I

i

NSO0_00214

t

I

L

S

I

I

r

I

sd

t

sd

t

r

NSO0_00531

t

I

L

I

I

r

t

r

I

i

I

N