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INSTANTANEOUS UNIT
Select the desired range by making the proper connections at the rear of the relay (See Internal
Connections Diagram).
rating.
Set the instantaneous unit to pick up at the desired current level.
2.
Unit�, ion the "Acceptance Test Section."
All the tests described above under Installation Tests must be performed at the time of installation.
In addition, if those tests described under the "Acceptance Tests Section" were not performed prior to
installation, it is recommended that they be performed at this time.
�
In view of the vital role of protective relays in the operation of a power system , t t is important
that a periodic test program be followed.
will vary depending upon environment, type of 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 of from one to two
years.
These tests are intended to e nsure that the relays have not deviated from their original setting.
deviations are encountered, the relay must be retested and serviced as described in this manual.
If
TIME OVERCURRENT UNIT
1.
Perform Pick-up test as described in the "Installation Section" for the tap in service.
2.
Perform the Time Tests as described in the "Installation Section."
INSTANTANEOUS UNIT
c
Check that the Instantaneous Unit picks up at the
"Acceptance Test Section."
TARGET AND SEAL-IN UNIT
1.
Check that the unit picks up at the values shown in Table
Check that the units drops out at
2.
CONTACT CLEAN lNG
For cleaning relay contacts, a flexible burnishing tool should be used.
strip of metal with an etched-roughened surface resembling in effect a superfine file.
action is so delicate that no scratches are left, yet is will clean off any corrosion thoroughly and
rapidly.
Its flexibility e nsures the cleaning of the actual points of contact.
abrasive paper or cloth of
SYSTEM TEST
0
Although this Instruction Book is primarily written to check and set the lAC relay, overall functional
tests to check the system operation are recommended at intervals based on the customer's experience.
TIME OVERCURRENT UNIT
If it is found during installation or periodic testing that the time overcurrent unit is out of
limits, the unit may be recalibrated as follows:
1.
Rotate time dial to No.
Where the
conta � ts
.
means of 1ts adJust1ng screw.
With the contacts just closin� at No. 0 time setting, there should be sufficient gap between the
stationary contact brush and 1 ts metal backing strip to ensure approximately 1/32" wipe.
Whenever possible, always select the higher range since it has higher continuous
PERIODIC CHECKS AND ROUTINE MAINTENANCE
It is recognized that the interval between periodic checks
or more of tap value.
30%
any kind to clean relay contacts.
0
time dial setting and check by means of a lamp that the contacts just close.
�
ust close can
be adjusted by running the stationary contact brush in or out by
.
Th1s screw should be held securely in its support.
GEK-3 40 55
desired current level, as outlined in the
XI.
SERVICING
1 1
See �setting the Instantaneous
This consists of a flexible
The polishing
Do not use knives, files,
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