SMY133-SMY134-SMP133 Operating Manual
For safety reasons, the instrument must be grounded before connection of other signals!
2.3.2 Power Supply
The supply voltage (in range according technical specifications) connects to terminals
AV1
(No. 9) and
AV2
(10) via a disconnecting device (switch – see wiring diagram). It must be located at the
instrument’s proximity and easily accessible by the operator. The disconnecting device must be
marked as such. A two-pole circuit breaker with the C-type tripping characteristics rated at 1A makes a
suitable disconnecting device. Its function and working positions, however, must be clearly marked.
In case of DC supply voltage the polarity of connection is generally free, but for maximum
electromagnetic compatibility the grounded pole should be connected to the terminal
AV2
.
Recommended wire type :
H07V-U (CY)
Recommended minimum conductor cross-section : 1.5 mm
2
Maximum conductor cross-section :
2.5 mm
2
2.3.3 Measured Voltages
The phase voltages measured are connected to terminals
U1
(12),
U2
(13),
U3
(14), the common
terminal to connect to the neutral wire is identified as
N
(11; it stays free at delta- (3-D) and Aron- (A)
connections). It is suitable to protect the voltage lines measured for example with 1A fuses. Measured
voltages can also be connected via instrument voltage transformers.
Recommended wire type :
H07V-U (CY)
Recommended minimum conductor cross-section : 1.5 mm
2
Maximum conductor cross-section :
2.5 mm
2
2.3.4 Measured Currents
The instruments are designed for indirect current measurement via external CTs only. Proper current
signal polarity (S1 & S2 terminals) must be observed. You can check the polarity by the sign of phase
active powers on the instrument display (in case of energy transfer direction is known, of course).
It is necessary to set the CT-ratio – see example below.
The I2 terminals stay free in case of the Aron (A) connection.
2.3.4.1 Current Type Current Inputs Instruments ( Models „X/5A“,
„X/100mA“ )
The current signals from 5A or 1A (or 0.1A for the „X/100mA“ models) instrument current transformers
must be connected to the terminal pairs
I11
,
I12
,
I21
,
I22
,
I31
,
I32
(No. 1 ÷ 6). At the “134” model, you
can connect the 4
th
current signal too to the terminals
I41
,
I42
(No. 7 ÷ 8).
Recommended wire type:
H05V-U (CY)
Recommended minimum conductor cross-section :
•
“X/5A” instruments :
2.5 mm
2
•
“X/100mA” instruments :
0.75 mm
2
Maximum conductor cross-section :
2.5 mm
2
10
