System Rapid Link
01/08 AWB2190-1430GB
16
Cable length
When defining the length of the power bus line, observe the
following:
• In the event of a short-circuit in a single-pole at the end of the
power bus – for example in the motor’s terminal board of the
last consumer – the upstream safety device must trip. The
magnitude of the short-circuit depends on:
– Cable lengths
– Conductor cross-section
– Short-circuit current at the incoming point
• Level of application-specific voltage drop. This depends on:
– Cable lengths
– Conductor cross-section
– Current consumption of motors
Through calculation of the short-circuit current and voltage drop
according to the IEE Wiring Regulations, ensure that the protective
functions are fulfilled.
You can calculate the cable length of the power bus as follows:
The national and regional standards (for example VDE 0113, EN
60204) must be observed and the necessary approvals (for
example UL) at the site of installation must be fulfilled.
When the device is operated in a UL-approved system, use only
UL-approved fuses, fuse bases and cables.
L =
U
0
x
1000
–
Z
v
–
Z
Stich
i
rm
z
power bus
L
=
lengt
h
u
0
= 230 V (no-load voltage 1-ph.)
i
r
m
= Tripping current of short-circuit release, e.g.
150 A for RA-DI
z
v
= e.g. 100 m
O
(series impedance of feeder)
Z
Stich
= 35,50 m
O
/m (spur line 1,5 mm
2
)
z
power bus
= 13,40 m
O
/m (power bus 4.0 mm
2
)
21,50 m
O
/m (power bus 2.5 mm
2
)
Figure 13: Demands placed on the RA-DI group protection device with
short-circuit
Precondition: The short-circuit current
I
k
must be greater than the
tripping current of short-circuit release
I
rm
.
I
k
is dependent on the impedance or length of the power bus and the
spur line (for Rapid Link about 2 m incomer plus 2 m motor cable)
h
You can obtain a calculation and engineering tool from
Moeller GmbH.
h
Attention!
When selecting the cable cross-section, take the voltage
drop under load conditions into account. The end user is
responsible for the observation of any other applicable
standards (for example IEC/EN 60204).
3
AC 400 V
h
, 50/60 Hz
RA-DI
I
rm
I
k
Q1
L
M
3
h
RA-MO
1.5 mm
2
I >
Summary of Contents for Rapid Link
Page 10: ...01 08 AWB2190 1430GB 6 ...
Page 40: ...01 08 AWB2190 1430GB 36 ...
Page 48: ...01 08 AWB2190 1430GB 44 ...
Page 70: ...01 08 AWB2190 1430GB 66 ...
Page 146: ...01 08 AWB2190 1430GB 142 ...
Page 162: ...01 08 AWB2190 1430GB 158 ...
