Technical data

16
• DOK-DIAX02-DDC01******-PRJ1-EN-E1,44 • 01.97
0.1 0.2 0.4 0.6 1 1.3 2 4 6 10 20
T (ms)
T
U
N
+∆U
U
N
U
N
∆U
∆U
2
DGUEBSPG
3
2.6
2.4
2.3
2.2
2
1.8
1.6
1.4
1.2
1.15
1.1
1
Grounded threephase
systems
3.3. Grounding Conditions
With the help of an autotransformer, voltages can be adapted to three-phase
mains witch is in reference to the ground (TN or TT mains). The DDC 1 can be
directly connected to 3 x AC 220 V mains.
There is an increased danger in ungrounded mains (IT mains) that overvoltages
will occur between the phases and the housing. The DDC 1 should only be
operated with such systems, if:
• it is connected across an isolation transformer or
• if the installation is protected with an overvoltage conductor.
3. Electrical Connections - Installation Guidelines
Connecting the DDC 1.2 across an isolation transformer offers the
best possible protection against overvoltage and the greatest
operating safety!
Permissible
overvoltage levels
The voltage between phase connections (A, B and C) and the DDC 1.2
housing can equal 230 V (effective).
Non-periodic overvoltages as per VDE 0160 between phases and housing are
acceptable for the DDC 1.2 to the extent as shown below:
Fig. 3.3: Permissible non-periodic voltages as per VDE 0160
The DDC 1.2 can be connected to 3 x AC 230 V mains.
The maximum permissible non-periodic overvoltage thus equals:
230V ⋅ 2⋅ 2.3 = 745V
Ungrounded
threephase systems