Page 822 - Din prodcuts 2020

8/82 ELECTRICAL INSTALL ATION SOLUTIONS FOR BUILDINGS 2CHC 420 001 C0201

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Energy efficiency
CT measurement current transformers with through primary

Technical features
CT… CTO TRFM
Standard secondary current [A] 5 A
Max. voltage for operation [kV] 1,2
Test voltage [kV] 3 a 50 Hz/1min
Residual current voltage at < 25 V rms
secundary terminals when security
CT circuit intervenes (only SELV
versions)
Short circuit rated thermal current [IpN] 40 per 1 sec. 60 per 1 sec. 40 per 1 sec.

Short circuit rated dynamic [Ith] 2,5 per 1 sec.
current
Permanent overload [IpN] 1,2
8
Safety factor [Fs] from ≤ 2 to ≤ 10 depending on the type and capacity
Frequency [Hz] 50-60
Air insulation class Class E B E
Terminals primary P1 - P2 (K - L); secondary s1 - s2 (k - l)
P1 (K) primary winding input
s1 (k) secondary winding input
P2 (L) primary winding output
s2 (l) secondary winding output
Housing Self-extinguishing thermoplastic resin V0
Protection degree IP30 IP20 IP20
Operating temperature [°C] -5...+50 -5...+50 -25...+50
Max. temperature on bars [°C] 70°C
Storage temperature [°C] -20...+80 -20...+80 -40...+80
Relative humidity 80%
Reference standard IEC EN 60044-1, IEC EN 61010-1
Secondary protection circuit IEC60364;
reference standards (only SELV IEC473.1.4; IEC556.3;
versions) CEI64-8-4;
CEI411.1.4.3;
CEI411.5.2; CEI411.2;
CEI473.1.4;
CEI473.2.3

CT and CTA current transformers
Used to transform primary currents (max. 6000 A) into .../5 A low secondary currents
indirectly supplying power to analogue and digital measurement devices. They are available
both with wound and through primary. In the first case they are provided along with the bar or
the primary terminal; in the second case they have a hole to insert in the bar or the cable which
forms the primary.
The rated current to the secondary windings is 5 A, in line with the offer of measuring devices.
CT ../1 are not employable with ABB mono-function and multifunction measuring devices. The
use of CT ../1 is needed in case of long wirings from CT secondary windings to the measuring
device; nowadays, the wide use of communication protocols doesn’t require the instrument to
be installed far from the line to measure.
The new SELV versions of the CT PRO XT and CT MAX guarantee maximum safety against
overvoltage and switchboard internal overheating thanks to the innovative electronic
protection circuit which automatically short-circuit the CT secondary winding in case
of accidental disconnection of its secondary terminals.