Rockwell Automation 1336T Wiring and Grounding Guide, (PWM) AC Drives - Manual (Page 28)

28 Rockwell Automation Publication DRIVES-IN001M-EN-P - March 2014
Chapter 2 Power Distribution
TN-S Five-wire System
TN-S Five-wire distribution systems are common throughout Europe, with the
exception of the United Kingdom and Germany. Leg-to-leg voltage (commonly
at 400V) powers three-phase loads. Leg-to-neutral voltage (commonly at 230V)
powers single-phase loads. Neutral is a current conducting wire, and connects
through a circuit breaker. The fifth wire is a separate ground wire. There is a
single connection between ground and neutral, typically in the distribution
system. Do not make connections between ground and neutral within the system
cabinets.
AC Line Voltage In general, all Allen-Bradley drives are tolerant to a wide range of AC line voltage.
Check the individual specifications for the drives you are installing.
Incoming voltage imbalances >2% can cause large unequal currents in a drive. Use
an input line reactor when line voltage imbalances are >2%.
AC Line Impedance To prevent excess current that can damage drives during events such as line
disturbances or certain types of ground faults, provide a minimum amount of
impedance in front of the drives. In many installations, this impedance comes
from the supply transformer and the supply cables. In some cases, an additional
transformer or reactor is recommended. If any of these conditions exist, consider
adding impedance (line reactor or transformer) in front of the drive:
• Installation site has switched power factor correction capacitors.
• Installation site has lightning strikes or voltage spikes in excess of 6000V
peak.
• Installation site has power interruptions or voltage dips in excess of
200V AC.
• The transformer is too large in comparison to the drive. See impedance
recommendations on
Table 4 on page 30 through Table 13 on page 41 .
L1
L2
L3
PEN or N
PE
IMPORTANT Tables 4 through 13 define the largest transformer size for each product
and rating based on specific differences in construction, and is the
preferred method to follow.