Publication 2098-IN003E-EN-P — April 2004
Connecting Your Ultra3000
3-7
The following examples (figures 3.7 and 3.8) illustrate grounded
three-phase power wired to single-phase Ultra3000 drives when
phase-to-phase voltage
exceeds
drive specifications.
A neutral must be connected when single-phase drives are attached to
a three-phase isolating transformer secondary. It is not necessary that
all three-phases be loaded with drives, but each drive must have its
power return via the neutral connection.
Figure 3.7
Single-Phase Amplifiers (One EMC Filter/Drive)
Note: Feeder and branch short circuit protection is not illustrated.
ATTENTION
!
Failure to connect the neutral can result in
supply voltage swings at the individual loads
(i.e., drives). This occurs when the neutral
point moves vectorially as a result of load
variations normally experienced by the
individual drives. The supply voltage swing
may cause undervoltage and overvoltage trips
on the drives, and the drive can be damaged if
the overvoltage limit is exceeded.
L1
L2
L3
L1
L2
L1
L2
L1
L2
TB1
L1
L2/N
TB1
L1
L2/N
TB1
L1
L2/N
L1
L2
L1
L2
L1
L2
E
E
E
Bonded Cabinet
Ground Bus
Transformer (WYE) Secondary
Ground Grid or
Power Distribution Ground
AC Line
Filter
AC Line
Filter
AC Line
Filter
Ground Grid or
Power Distribution Ground
Ultra3000 (System A)
Single-Phase AC Input
TB1 Terminals
Ultra3000 (System B)
Single-Phase AC Input
TB1 Terminals
Ultra3000 (System C)
Single-Phase AC Input
TB1 Terminals
Grounded Neutral
Grounded Neutral
IMPORTANT
Providing an EMC line filter for each drive is the
preferred configuration, and required for CE
compliance.
