SIEMENS
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Siemens D 35 · 2017
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Configuration
(continued)
5
SINAMICS G120P Cabinet, converter cabinet units
SINAMICS G120P Cabinet, 75 kW to 630 kW
SINAMICS G120P Cabinet
Current-carrying capacity according to IEC 60364-5-52 at 40 °C (104 °F)
Cables must be connected in parallel for higher currents.
Note:
The recommendations for the North American market in AWG or
MCM should be taken from the corresponding standards NEC
(National Electrical Code) or CEC (Canadian Electrical Code).
Grounding and protective conductor cross-sections
The protective conductor must be dimensioned taking into
account the following data:
•
In the case of a ground fault, no impermissibly high contact
voltages resulting from voltage drops on the PE conductor
caused by the ground fault current may occur (< 50 V AC or
< 120 V DC, IEC 61800-5-1, IEC 60364, IEC 60543).
•
The PE conductor should not be excessively loaded by any
ground fault current it carries.
•
If it is possible for continuous currents to flow through the
PE conductor when a fault occurs, the PE conductor cross-
section must be dimensioned for this continuous current.
•
The PE conductor cross-section should be selected
according to IEC 60204-1, IEC 60439-1, IEC 60364.
Note:
The recommendations for the North American market in AWG or
MCM should be taken from the corresponding standards NEC
(National Electrical Code) or CEC (Canadian Electrical Code).
Switchgear and motors are usually grounded separately via a
local ground electrode. With this constellation, the ground fault
current flows via the parallel ground connections and is divided.
In spite of the relatively small protective conductor cross-
sections used in accordance with the table above, no inadmis-
sible touch voltages occur with this grounding system.
However, from experience gained with different grounding
constellations, we recommend that the ground cable from the
motor returns directly to the converter. For EMC reasons and to
prevent bearing currents – for higher power ratings – symmet-
rical, 3-wire, three-phase cables should be preferentially used
instead of four-wire cables. For 3-wire cables, the protection or
PE wire must be routed separately or arranged symmetrically in
the motor cable. The symmetry of the PE conductor is achieved
using a conductor surrounding all phase conductors or using a
cable with a symmetrical arrangement of the three phase
conductors and three ground conductors.
Through their high-speed controllers, the converters limit the
load current (motor and ground fault currents) to an rms value
corresponding to the rated current. We therefore recommend the
use of a PE conductor cross-section analogous to the phase
conductor cross-section for grounding the control cabinet.
Cross-section 3-wire cable
Copper cable
Aluminum cable
Single routing
Several cables lying next to
one another
1)
Single routing
Several cables lying next to
one another
1)
mm
2
A
A
A
A
3 × 2.5
22
17
17
13
3 × 4
30
23
23
18
3 × 6
37
29
29
22
3 × 10
52
41
40
31
3 × 16
70
54
53
41
3 × 25
88
69
68
53
3 × 35
110
86
84
65
3 × 50
133
104
102
79
3 × 70
171
133
131
102
3 × 95
207
162
159
124
3 × 120
240
187
184
144
3 × 150
278
216
213
166
3 × 185
317
247
244
190
3 × 240
374
292
287
224
Cross-section,
line conductor
Minimum cross-section, external protective
conductor
mm
2
mm
2
up to 16
Minimum cross-section of external conductor
16 ... 35
16
from 35
At least half the cross-section of external
conductor
1)
A maximum of 9 cables may be routed directly next to one another horizon-
tally on a cable tray.
© Siemens AG 2017