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GEK-90636
Relay Contacts
The relay contacts consist of normally open (NO) and normally closed (NC)
contacts for each of the frequency measuring units.
Tests
For the following test.s refer to figure 9 for test connections, and to figure 17 and 20
for the front views of the SFF2O1, and 204 respectively. For the SFF202 refer to the
SFF204 front view.
Test the relay in accordance with the function it is set for. Such as Over Frequency,
Under Frequency, Rate of Change or Restore.
Note: The trip LEDs will only light and seal in if lOOma of current flows through the
output contacts.
Over Frequency Relay Tests
The relay will trip when the frequency under test exceeds the frequency setpoints for
more than three cycles.
Table IV
Switch Settings
Set
Under
Point
t Frequency
Mode
ROC
Time
Voltage
Delay
Cutoff
SFF2O1
Fl
5Oor6Ohz
over
-
1.5sec
35%
SFF2O2
Fl
50 or 60hz
over
out
1.5sec
35%
F2
50 or 60hz
over
-
1.5sec
SFF2O4
Fl
50 or 60hz
over
out
l.5sec
35%
F2
50 or 60hz
over
out
1.Ssec
F3
50 or 60hz
over
out
1.5sec
F4
50 or 60hz
over
-
1.5sec
T The relay can be tested at other frequencies if desired. To do so, set the frequency
and adjust the inputs based on that setting.
Over Frequency Test With Variable Frequency Generator
1. Apply the rated supply voltage between stud(1) and stud(2) (either polarity).
2. Set the frequency generator at (0.5hz) below the setpoints. For example, set
the frequency to 59.5hz for 60hz and 49.5hz for 50hz rated setpoints. Apply the
frequency source at 115 Vrms between stud(5) and stud(6). Then increase the
frequency (0.5hz) above the setpoint. Maintain the frequency at the higher
setting for 3 cycles plus 1.5sec to produce an output.
Verify that the following occurs during the over frequency. The test target
LEDs "Fl" to "F4" light. The "TB" test targets and the trip target LEDs "Fl"
to "F4" light after the
1.5
second time delay. And the output relay contacts
have tripped, as indicated by the trip targets.
12
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