The table below shows the line-to-ground voltages in relation to the line-to-line
voltage for each grounding system.
Electrical power system typeU
L3-G
U
L2-G
U
L1-G
U
L-L
TN-S system (symmetrically grounded)0.58·X0.58·X0.58·XX
Corner-grounded delta system (nonsym-
metrical)
01.0·X1.0·XX
Midpoint-grounded delta system (non-
symmetrical)
0.5·X0.5·X0.866·XX
IT systems (ungrounded or high-resist-
ance-grounded [>30 ohms]) nonsymmet-
rical
Varying level
versus time
Varying level
versus time
Varying level
versus time
X
TT system (the protective earth connec-
tion for the consumer is provided by a
local earth electrode, and there is anoth-
er independently installed at the gener-
ator)
Varying level
versus time
Varying level
versus time
Varying level
versus time
X
￭
Disconnecting internal EMC filter or ground-to-phase varistor - frames
R1…R3
Extra screws to configure the drive for different networks are provided in the drive
shipment, see the table in page 178.
To disconnect the internal EMC filter or ground-to-phase varistor:
1. Do the steps in section Electrical safety precautions (page 24) before you start
the work.
2. Open the front cover, if not already opened, see page 186.
3. The internal DC EMC filter is disconnected by default with no screw or with a
plastic screw (3a).
4. To disconnect the ground-to-phase varistor, remove the metal varistor screw
(4a) and place it in the storage place (4b), or replace it with the plastic screw
provided in the package.
180 Electrical installation – North America
To Next Page
Loading...
