1-4 Installation/Wiring
Ungrounded Distribution Systems
Disconnecting MOVs
To prevent drive damage, the MOVs connected to ground shall be 
disconnected if the drive is installed on an ungrounded distribution 
system where the line-to-ground voltages on any phase could exceed 
125% of the nominal line-to-line voltage. To disconnect these devices, 
remove the jumper shown in the Figures 1.1
 and 1.2.
1. Turn the screw counterclockwise to loosen.
2. Pull the jumper completely out of the drive chassis.
3. Tighten the screw to keep it in place.
Figure 1.1   Jumper Location (Typical)
Figure 1.2   Phase to Ground MOV Removal
AC Supply Source Considerations
ATTENTION:  PowerFlex 40P drives contain protective MOVs that 
are referenced to ground. These devices must be disconnected if the 
drive is installed on an ungrounded or resistive grounded distribution 
system.
Important:
Tighten screw after 
jumper removal.
R/L1
S/L2
T/L3
123
4
Three-Phase
AC Input
Jumper