Power Supply System Requirements - ABB OmniCore V250XT Type B Product Manual

3.5.3 Power supply system requirements

Definition of the power supply system
IEC 60364 defines three different types of mains grounding using the two-letter
codes. These are TN, TT, and IT.
First letter
T
I
Second letter
T
N
In the following section the transformer configuration refers to the transformer
secondary side. Configuration of the transformer primary side is not discussed in
this context.
Allowed power supply systems
Only the following systems are allowed by ABB:
TN−S system
PE and N are separate conductors that are
connected together only near the transformer.
xx1700001310
Isolation transformer
A three-phase isolation transformer between the mains supply and the control
cabinet is required for any of the below conditions:
Product manual - OmniCore V250XT Type B
3HAC087112-001 Revision: A
Type of ground connection
Direct connection of one point to ground.
Not connected to ground or connected to ground via a high impedance.
Connection between ground and the device being supplied
Direct connection of one point to ground.
Direct connection to neutral at the origin of installation, which is connec-
ted to the ground
Note
The networks must be symmetrical with respect to protective earth.
• If the available grid do not comply with the above described allowed power
systems, as mentioned in
• When the mains supply is shared with a pressing machine, frequency
converter, or other large industry equipment that may cause the power supply
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3 Installation and commissioning
3.5.3 Power supply system requirements
TN−C system
A combined PEN conductor is used as both
a PE and an N conductor.
L1
L2
L3
N
PE
xx1700001311
Allowed power supply systems on page
L1
L2
L3
PEN
79.
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