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Checking the matching transformers
The three matching transformers of the relay are
checked one by one. Apply voltage to the relay
and compare the voltage value read from the
display of the relay with the voltage value shown
by the voltmeter. The measurements can be
performed at the rated voltage of the relay.
Checking the overvoltage stage U>
Set the switches of the SGR switchgroup as
follows before starting the test:
Switch Position
11
20
31
40
50
60
71
80
The following relay functions are obtained:
Output relay Function
(terminals)
A (65-66) Trip signal of stage U>
B (68-69) (Trip signal of stage U<)
C (80-81) Signal on operation of
stage U>
D (77-78) Start signal of stage U>
E (70-71-72) Self-supervision signal
Checking the start function
Apply test voltage to terminals 13-14 or 13-15
depending on the used energizing input. Close
switch S1 and increase the voltage slowly until
the overvoltage stage starts and indicator L2 is
lit. Read the start voltage value from the voltme-
ter.
Operate time t>
Definite time characteristic
If possible, set the test voltage at 2 x the set start
voltage of the overvoltage stage. Note! The
maximum voltage withstand of 2 x U
n
must not
be exceeded. The timer is started by switch S1,
when it is closed and stopped by contact 65-66,
when output relay A picks up.
The operation of output relay C is indicated
with indicator L3, when it is lit.
When the relay starts the LED indicator U> in
the lower right corner of the front panel is lit
with yellow colour. When the overvoltage stage
operates the LED indicator turns red.
Inverse time characteristic
When the relay has been set for inverse time
characteristic, the test is performed by mea-
suring the operate time at two voltage values,
e.g. 1.1 x U> and 1.4 x U> and by comparing the
operate times with the operate times obtained
from the characteristic curves.
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