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GEK-90636
DESCRI PTION
The type SUP relays are digital frequency relays that measure the system
frequency. Three versions of the 5FF are available providinç one, two, or four
frequency setpoints. Each S the frequency measuring elements is independent, and
can be independently set for under frequency, over frequency, or restore operation,
and has I form C output contact. Each element may be set for any freQuency over the
ranse of 40 to 79.9 Nz in 0.1 Hz steps in the SFF2O(-)A and 0.01 Hz steps in the
SFF2O(-)B. If a frequency setting outside of the acceptable range is made, that
frequency will be prevented from operating.
A simple rate-of-change (ROC) feature can be enabled on the multi-frequency
models. When this feature is enabled, an output will be produced at the higher set
frequency if the next lower frequency setpoint is reached before the timer associated
with the higher set frequency can time out. For example, assume that a two setpoint
relay is set to operate at 59 Hz with an 0.75 second delay. and at 58 Hz with a I second
delay. If 58 Hz is reached 0.5 seconds after 59 Hz is reached, the output relay
associated with the 59 Hz setting will operate at that time rather than waiting until
the full 0.75 seconds has expired. Similar performance can be obtained between the
second and third setpoints and between the third and fourth setpoints in the four
setpoint relay.
The minimum operating time for an under frequency, over frequency, or restore
output to occur is 3 cycles. In addition, an adjustable timer is provided for each
frequency setpoint wherein a delay can be added to the output. When used in the
under frequency or over frequency mode this time is used to delay the output,
whereas it is
used
to prolong the output when the function is used in the restore mode.
Timer ranges are shown below:
Mpdel
Timer Ranae
SteDs
Sfl20(-)A:
0 to 1.55 seconds
.05 second
SF'F20(-)B:
1.0 to 255 milliseconds
1 millisecond
0.lto 25.5
seconds
0.lsecond
The AC undervoltage cutoff function operates to block all outputs whenever the
input voltage is less than the undervoltage cutoff setting. The function has a dropout
time Sapproximately one-half(1/2) cycle and a pickup time dapproximately one (1)
cycle. The function is adjustable over the range 535 to 95
percent
inS percent stçps.
Note that the percentage is
based
on 120 volts, the nominal rating d'the relay. For
example, if the input voltage is 110 volts, and the cutoff level is set to 50
percent,
cutoff will occur at 60 volts (50 percent of 120) rather than 55 volts (50 percent of
These instructions do not purport to cover all details or variations in equipment nor to prouide for
evely possible contingency to be met in connection with installation, operation or maintenance.
Should funher information be desired or should particular problems arise which are not covered
sufficiently flu' the purchaseri purposes. the matter should be referred to the General Electric
Company.
To the extent required the products described herein meet applicable ANSI, IEEE and NEMA
standards, but no such assurance is given with respect to local codes and ordinances because they
vaiy gnat4y.
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