Specifications are subject to change without notice (19.07.06) 1
Current and Voltage Controls
•3-phase current metering transformers
for use with current control relays
•Measuring ranges:
A74-10 5: 0.5 - 5 AAC
A74-10 20: 2 - 20 AAC
A74-11 100: 10 - 100 AAC
A74-11 500: 50 - 500 AAC
Product Description
3-phase current transformer
measures on all three phases.
Output voltage proportional
Ordering Key
Type
Input current
to measured amplitude of the
rms-value of the normal
phase current.
Type Selection
Input current Type no.
5AAC A74-10 5
20 AAC A74-10 20
100 AAC A74-11 100
500 AAC A74-11 500
Input Specifications
A74-10 5 A 74-10 20 A 74-11 100 A 74-11 500
Output voltage
(TA=20°C = 68°F), RL=9.5 kΩ)
0.4 - 4 Vp0.4 - 4 Vp0.4 - 4 Vp0.4 - 4 Vp
Output impedance <700 Ω<200 Ω< 40 Ω< 10 Ω
T
olerance of output voltage
@rated input current ± 5% ± 5% ± 5% ± 5%
T
emperaturevariation ±0.1% per °C±0.1% per °C ± 0.1% per °C ± 0.1% per °C
Rated insulation voltage (cable)
250 VACrms 250 VACrms 250 VACrms 250 VACrms
Output Specifications
Current Transformer, 3-Phase
Types A 74-10, A 74-11
A74-10 5 A74-10 20 A74-11 100 A74-11 500
Current range 0.5 - 5 AAC 2-20 AAC 10 - 100 AAC 50 - 500 AAC
Max. current (continuously) 20 AAC 50 AAC 250 AAC 750 AAC
Max. overload current (t = 30 s)
40 AAC 85 AAC 325 AAC 1000 AAC
Rated insulation voltage
Input-output 1000 VACrms 1000 VACrms 1000 VACrms 1000 VACrms
Overvoltage category IV (IEC 60664) IV (IEC 60664) IV (IEC 60664) IV (IEC 60664)
Dielectric strength
Dielectric voltage 6 kVACrms 6kVACrms 6kVACrms 6kVACrms
Rated impulse withstand volt. 12 kV (1.2/50 µs) 12 kV (1.2/50 µs) 12 kV (1.2/50 µs) 12 kV (1.2/50 µs)
Power consumption <0.1 W@5 A < 0.25 W@20 A < 1.5 W@100 A < 21 W@1500 A
A74-10 5
2Specifications are subject to change without notice (19.07.06)
A74-10, A 74-11
General Specifications
Pollution degree 3(IEC 60664)
Ambient temperature
-20 to + 60°C (- 4 to + 140°F)
Housing
Dimensions A74-10 120 x 45 x 16 mm
A74-11 150 x 114 x 23
Material ABS
Weight A74-10 200 g
A74-11 750 g
Connection cable 2 m PVC, 4 x 0.4 mm2
Approval UL
CE Marking Yes
The current metering trans-
former is connected to the
current control relays H 475
as follows:
Red core to term. 5 -U1.
White core to term. 6 -U2.
Yellow core to term. 7 -U3.
Black core to term. 8.
(starpoint - neutral).
The metered conductor is
drawn through the central
hole of the current metering
transformer. Drawing the con-
Mode of Operation
ductor through the hole sever-
altimes makes it possible to
meter currents below the no-
minal range.
If the conductor is drawn
through the central hole e.g. 5
times, the metering trans-
former will register 50 A when
the current in the conductor is
10A.
In amplitude and phase the
output voltage is proportional
to the phase current metered.
Wiring Diagrams
Output voltage
A74-10 .. A74-11 ..
Input current
Red
White
Yellow
Black
U1Red
Black
U3Yellow U2White
U1Red
U2White
U3Yellow
Black
Dimensions
Correct connection
Incorrect connection
