Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - ForGe Control (PanelView 550) - Manual (Page 36)

36 Rockwell Automation Publication 7000-UM151E-EN-P - January 2013
Chapter 3 Component Definition and Maintenance
Operation
Arrester operation without a gap is the same as that of MOVs in the TSN.
Depending on design, the arrester may also have a gap. Both gapped and un-
gapped arresters provide adequate overvoltage protection.
The arresters can withstand most commonly-seen bus transients within their
capability. If there is a harmonic filter on the MV bus connected to the drive, the
filter must satisfy relevant international or local standards, such as IEEE Std
1531— Clause 6.4, to avoid high inrush currents.
The surge arrester is certified as per ANSI/IEEE Std C62.11-1993. Certification
tests include high current short duration tests, low current long duration tests,
and fault current withstand tests. The fault current withstand tests consist of
different combinations of kA and number of cycles, including a 20kA 10-cycle
test, under which the arresters are non-fragmenting without expelling any
internal components.
When the incoming energy exceeds the handling capability of the arrester and
causes arrester failure, the housing splits open to vent without causing damage to
any adjacent components.
Replacing the Surge Arrester
1. Isolate and lock out all power to the drive.
2. Wait a minimum of ten minutes for the drive to discharge stored energy.
3. Observe the location of the connecting leads.
4. Use proper method to ensure the leads are at ground potential. Use
temporary grounding when necessary.
5. Detach the connecting leads.
6. Loosen the bolt that attaches the surge arrester to the ground bus. Remove
the arrester. Remove temporary ground when applicable.
7. Replace the surge arrester with an equivalent one (make sure that the
voltage rating is the same).
8. Connect the leads to the surge arrester.
ATTENTION: To prevent electrical shock, disconnect the main power
before working on the drive. Verify that all circuits are voltage-free using
a hot stick or appropriate voltage-measuring device. Failure to do so may
result in injury or death.