Rockwell Automation 1336T FORCE Series B - Manual (Page 29)

Chapter 2
Installation/Wiring
2–9
Unbalanced Distribution Systems
The drive is designed for use with conventional three–phase supplies which
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 the drive must not be used directly with
supplies where one phase is grounded (Grounded Delta). In such cases an
isolation transformer must be used to provide a supply balanced with
respect to ground.
Ungrounded Distribution Systems
All 1336 FORCE drives are equipped with an MOV (Metal Oxide Varistor)
that 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–phase MOV
connection could become a continuous current path to ground. MOV
line–to–line and line–to–ground voltages should not exceed the values
listed below. Exceeding these values may cause physical damage to the
MOV.
1 2 3 4
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 - G
240 480 600
140 140 150
220 220 220
Line–to–Line MOV Rating
Energy Rating = 320 Joules
Turn On Voltage = 1020V (nominal)
Line–to–Ground MOV Rating
Energy Rating = 380 Joules
Turn On Voltage = 1330V (nominal)
Input Devices
Starting and Stopping the Motor