User Manual V 1-4.XX User guide

2-26 Mounting and Wiring Your 1336 IMPACT Drive
Unbalanced Distribution Systems
The drive is designed for use with conventional three-phase supplies
that are symmetrical with respect to ground. Surge suppression
devices are included to protect the drive from lightning-induced
overvoltages between line and ground. For this reason, we
recommend a neutral grounded system. The drive works with a
grounded phase, but you may want to use an isolation transformer to
provide a supply balanced with respect to ground.
Ungrounded Distribution Systems
All 1336 IMPACT drives are equipped with a MOV (Metal Oxide
Varistor). The MOV provides voltage surge protection and
phase-to-phase plus phase-to-ground protection which is designed to
meet IEEE 587. The MOV circuit is designed for surge suppression
only (transient line protection), not continuous operation.
With ungrounded distribution systems, the phase-to-ground MOV
connection could become a continuous current path to ground. MOV
line-to-line and line-to-ground voltages should not exceed the input
voltage rating shown in Appendix A, Specifications. Exceeding these
values may cause physical damage to the MOV.
Figure 2.7
MOV Ratings
!
ATTENTION: To guard against personal injury and/or
equipment damage caused by improper fusing, use only
the recommended line fuses specified in the tables in the
frame-specific chapters. Branch circuit breakers or
disconnect switches cannot provide this level of
protection for drive components.
1234
Joules = (B)
Ground
Three-Phase
AC Input
T
S
R
Joules = (A)
Joules = (A)
Joules = (A)
Line-to-Line MOV Rating
Energy Rating = 2 x Line-Line Rating (A)
Line-to-Ground MOV Rating
Energy Rating = Line-Line (A) + Line-Ground (B)
Frame Reference
Device Rating (V)
Line-Line (A)
Line-Ground (B)
B - C
240 480 600
160 160 160
220 220 220
A
240 480 600
160 140 NA
220 220 NA
D - H
240 480 600
140 140 150
220 220 220