Acceptance Tests; Visual Inspection; Mechanical Inspection; Electrical Tests - GE STD15C Instructions Manual

the relay has not been

VISUAL INSPECTION

Check the nameplate stamping
relay received agree with the
Remove the relay from its case and chock by visual Inspection that there are no broken
molded parts or other signs of physical damage and that all screws are tight.
INSPECTION
Check the
that they operate smoothly without noticeable friction or binds.
units which should agree with values given under the section on
It is
1. Minimum pickup of main operating unit.
2. Minimum pickup of the Instantaneous overcurrent unit.
3. A single check
A single check point on the slope characteristic curve for
4.

TEST FACILITIES

In order to facilitate tests, the following test
1. Two load boxes for regulating the test currents.
2. Three
3. A test rectifier for checking the relays response to the second harmonic.
4. One indicating lamp.
5. single pole double
6. A double pole single throw line
Chock the
switches and are open and current passes through the differential circuit only. For example, with
a relay with a 25 percent slope and at the 2.9 ampere ratio matching taps, the main unit should pick
at of tap rating plus or minus 10 percent, or the pickup should be between 0.78 and 0.96
To check that the main unit has picked up a source of DC pwer at rated voltage should
amperes.
connected shown Fig. 12, and the Indicating lamp will provide a signal showing that the main unit
has operated.
For an additional pickup test, the pickup should be 1.5 amperes with current flowing
and 6 and the tap plugs in the 5 ampere tap, and the 25 percent slope tap position. If the pickup is
between 1.35 and 1.65 amperes, no adjustment should be made.
variations than most protective relays, but due to the relay design and application, the relay accuracy
is entirely adeuqate under all conditions even during transformer magnetizing inrush or severe fault
the selector switch,
the section on INSTALLATION PROCEDURE.
The instantaneous
The pickup should be about 8 times tap rating.
Check through current restraint as described under section on INSTALLATION PROCEDURE.
Courtesy of NationalSwitchgear.com
the relay an inspection and acceptance test
in and that the relay calibrations are unchanged.
insure that the model number. rating and calibration range of
of the telephone type relay and instantaneous overcurrent unit manually to see
that the electrical tests be
on the restraint characteristic.
(2 A.C. and O.C.) for measuring the test currents.
switch selector.
unit connections shwn In Fig. 12.
in the A position,
unit should be chocked by passing a high current through the 5-6

ACCEPTANCE TESTS

Check the contact gap and
is
The pickup of the relay-has wider
check the
14
be to insure that
upon receipt of
slope to be used.
this test. the selector
terminals 5
current restraint described
cracked
of these
relay.
a