Control cables, Galvanic isolation barriers – TREND NX Variable Speed Drives User Manual
Page 79
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CABLING AND CONNECTIONS
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6
6.2.1.1 Control
cables
The control cables shall be at least 0.5 mm
2
screened multicore cables, see Table 6-1. The maximum
terminal wire size is 2.5 mm
2
for the relay terminals and 1.5 mm
2
for other terminals.
Find the tightening torques of the option board terminals in Table below.
Tightening torque
Terminal
screw
Nm lb-in.
Relay and
thermistor
terminals
(screw M3)
0.5 4.5
Other terminals
(screw M2.6)
0.2 1.8
Table 6-8. Tightening torques of terminals
6.2.1.2
Galvanic isolation barriers
The control connections are isolated from the mains potential and the GND terminals are permanently
connected to ground. See Figure 6-26.
The digital inputs are galvanically isolated from the I/O ground. The relay outputs are additionally double-
isolated from each other at 300VAC (EN-50178).
Figure 6-26. Galvanic isolation barriers
L1 L2 L3
U V W
RO1/1
RO1/2
RO1/3
RO2/3
RO2/2
RO2/1
10Vref
GND
GND
+24V
AI1
AI2+
AI2 -
DIN1...
DIN3
CMA
DIN4...
DIN6
CMB
AO1+
AO2 -
DO1
nk6_1 5
TI1+
TI1-
Contro l I/O
ground
Digital input
group A
Digital input
group B
Analogue
output
Digital
output
Control
board
Control
panel
Gate drivers
Power
board