Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control - Manual (Page 275)

Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014 275
Component Definition and Maintenance Chapter 5
5. Replace the MOV (polarity is not an issue).
6. Continue by replacing the screws and connecting links.
Surge Arresters Description
Heavy duty distribution class surge arresters are used for transient overvoltage
protection in the drives with AFE rectifiers. The arresters are certified as per
ANSI/IEEE Std C62.11-1993.
The surge arresters are basically MOVs, with or without an air gap in series,
packed in sealed housing. They provide overvoltage protection similar to what
the TSN module does. They differ from the TSN in that fusing is not required
for the operation of surge arresters.
There are 3 types of surge arresters depending on the voltage class of the drive as
shown in the table below:
The most severe temporary overvoltage occurs when one phase is grounded in an
ungrounded system. The full line-to-line voltage is applied to the arrester in this
case. The arresters are designed to operate under this condition continuously
without any problems as shown by their Maximum Continuous Operating
Voltage (MCOV) rating.
There are three Y-connected surge arresters attached to the incoming MV lines.
The neutral point of the arresters is connected to the ground bus.
IMPORTANT Each MOV panel is grounded. Ensure that one MOV (see Figure 226 for
location) is connected to the grounding lead.
Drive voltage 2.4 kV 3.3 kV, 4.16kV, 4.8 kV 6.0-6.9 kV
Arrester rating (RMS) 3 kV 6 kV 9 kV
Arrester MCOV (RMS) 2.55 5.10 7.65