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4 Installation and Testing
4.7.5
Instantaneous Overcurrent Pickup Test
The phase current pickup of the relay will be set at the factory
to operate on one of the two available ranges: HIGH or LOW. If
ground current is monitored , it will also be set for one ofthe two
ranges. Determine which range your relay is set for by the
indication of the tap range on the front panel. (One for phase and
one for ground.)
A
When testing the instantaneous element, the
thermal rating of the relay must mot be
exceeded . The maximum continuous cur
rent rating for each input is five times tap or
20 A, whichever ·is Jess . The one-second
current rating for each input is 50 times tap
or 500 A, whichever is less. For ratings at less
than one second, refer to formula on Page
41 .
Verify instantaneous overcurrent pickup as follows:
1 .
After performing the "Preliminary Steps" (Page 1 9), con
nect the input current source to terminals 7 and 8 on the
relay case (Phase A).
2 .
Load .50 into the Phase Instantaneous #1 register. (Ap-
pears as Pin 1 in the display, and in Table 3, on Page 1 1 .)
3 .
Set the PHASE TAP switch t o position A .
4 .
Starting from 0 A, slowly increase the input current source
until the INST 1 output contact closes. This should occur at
3/4 the value shown on the front panel table for TAP A.
5.
Adjust the current source so that the JNST 1 relay opens.
The current applied should be above 71 .25% of the TAP
value (reference the front panel table}.
6.
Repeat steps 3 through 5 above with the PHASE TAP
switch set to B, C, D, E, F, G, H , I, and
7 .
I f Option 1 -2 i s present and i s used as lnst 2 , , follow the
procedures of steps 2 through 6 for testing the Instanta
neous 2 pickup and output.
C AUTION
J
successively.
NOTE
If this is a single-phase relay, this completes the
Instantaneous Overcurrent Pickup Test. If this is a
three-phase relay, perform steps 8 through 1 2 below.
If a two-phase-with-ground relay, perform steps 8, 9,
1 2 , and 1 3 . lf three-phase-with-ground, perform all of
the following steps.
8.
Disconnect the input current source from terminals 7 and
8 (Phase A) and connect it to terminals 1 4 and 1 5 (Phase
B).
Repeat steps 2 through 7 above for Phase B.
9.
10. Disconnect the input current source from terminals
1 5 (Phase B) and connect it to terminals 1 7 and 1 8 (Phase
C).
1 1 . Repeat steps 2 through 7 above for phase C.
1 2. Disconnect the input current source from terminals 1 7 and
1 8 (Phase C) and connect it to terminals 1 3 and 1 6
(Ground).
1 3. Repeat steps 2 through 7 above for ground.
4.7.6
Testing of Option 1 -2 Command C lose
Function
This function can only be used and tested if the Communications
Option is present, and a Power Monitor unit or Power Monitor
PC unit is present.
Close the 52b contact input on the relay (terminals 3 and 9)
1 .
which simulates the open breaker.
Select the "Command Close" command in the Power
2 .
Monitor. For detailed instructions refer to the Siemens
Power Monitor™ Display and Monitoring Unit (Manual SG-
401 8-01 }.
3.
You should observe the closure of the programmable
output contact (terminals 5 and 6).
4.
Open the 52b contact input. You should observe the
programmable output contact open.
Repeat step 2 . Terminals 5 and 6 should not close.
5.
Page 24
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