GEK-49865
Instantaneous Unit
Per form a pickup test at system frequency, as outlined in the
ACCEPTANCE
TESTS
section.
PERIODIC CHECKS AND ROUTINE MAINTENANCE
In view o f the vital role o f protective relays in the operation o f a power system,
it is important that a periodic test program be follo\'ied. It is recognized that the
interval between periodic checks will vary depending upon environment, type o f relay
and the user•s experience with periodic testing.
Until the user has accumulated
enough experience to select the test interval best suited to his individual
requirements, it is suggested that the points listed below be checked at an interval
o f from one to two years.
These tests are intended to make sure that the relays have not deviated from their
original settings.
I f deviations are encountered, the relay must be retested and
serviced as described in the
SERVICING
section o f this manual.
T IME OVERVOLTAGE UN IT
1.
Per form pickup test as described in the
INSTALLATION
section.
2.
Per form the time tests as described in the
INSTALLATION
section.
H IGH-SE ISM IC TARGE T AND SEA L- IN UN IT
1.
Check that the unit picks up at the values shown in Table V II in the
ACCEPTANCE
TESTS
section
)
.
2.
Check that the unit drops out at 25% or more o f tap value.
H IGH-SE ISM IC INSTANTANE OUS UNIT
Per form a pickup test at system frequency, as outlined in the
ACCEPTANCE TESTS
section.
C ONTA C T C LEAN ING
For cleaning relay contacts, a flexible burnishing tool should be used.
This
consists o f a flexible strip o f metal with an etched -roughened sur face, resembling
in e ffect a super fine file. The polishing action is so delicate that no scratches
are le ft, yet it will clean o ff any corrosion thoroughly and rapidly.
The
flexibility o f the tool ensure
s
the cleaning o f the actual points o f contact.
Do not use knives, files, abrasive paper or cloth o f any kind to clean relay
contacts.
Knives or
files may leave scratches which increase arcing and
deterioration o f the contacts. Abrasive paper or cloth may leave minute particles
o f insulating abrasive material in the contacts and thus prevent closing.
The burnishing tool described above can be obtained from the factory.
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