Page 23 - SACE Tmax XT - Technical Catalogue

INSTALL ATION 1/19
01

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Special applications

Use of direct current apparatus

Variation in magnetic tripping
The thermal-magnetic trip units of the SACE Tmax XT circuit-breakers are suitable for use in direct cur-
rent applications. For the protection thresholds against short-circuits, correction values (Km) must be
used, according to the type of distribution network and to the number of poles to be connected in series
(the thermal threshold does not undergo any alteration).
The correction value to be used can be found in the following tables.
Connection diagrams of poles in an insulated network
Insulated network
Un ≤250 ≤500 ≤750
+ – + – + – + – + –

Protection + insulation function LOAD LOAD LOAD LOAD LOAD

XT1 1.6 1.6
XT2 1.5 1.5
XT3 1.35 1.35
XT4 1.5 1.5 1.5
XT5 1.1 1.1 1.1
XT6 1.1 1.1 1
Connection diagrams of poles in a network with one grounded polarity

Network with one grounded polarity
Un ≤250 ≤500 ≤750
+ – + – + –

Protection + insulation function LOAD LOAD LOAD

+ – + – + –
Protection function

XT1 1.6 LOAD LOAD LOAD
XT2 1.5 1.5 1.5
XT3 1.35 1.35 1.35
XT4 1.5 1.5 1.5 1.5
XT5 1.1 1.1 1.1
XT6 1.1 1.1 1
Note: in the considered connections, the earthed polarity is the negative one.