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7000 "A" Frame
Drive input power from
line terminals
U
Figure 4.6 – Surge Arresters
Operation
The operation of arresters without a gap is the same as that of MOVs.
Depending on design, the arrester may also be gapped. Both gapped and un-
gapped arresters provide adequate overvoltage protection.
The arresters are able to withstand or ride through most commonly seen bus
transients within their capability. However, caution should be taken if there is
a harmonic filter on the MV bus to which PF7000 is connected. The filter
should 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 and
without expelling any internal components.
When the incoming energy exceeds the handling capability of the arrester and
causes arrester failure, the housing is designed to split open to vent without
causing damage to any adjacent components.
Field Test and Care
No field testing is necessary. The arresters do not require special care.
However at very dusty sites, it is suggested to clean the arrester when the
whole drive is cleaned.
Component Definition and Maintenance
W
V
Heavy duty
distribution
class surge
arrester
4-7
7000A-UM151E-EN-P - October 2018
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