Toshiba GRT100 Series, Instruction Manual

Page: 121 / 270

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120
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6 F 2 S 0 7 8 9
6.5.1.3 5F element
The testing circuit is shown in Figure 6.5.6.
Current
source
TB 1
DC
voltmeter
TB 4
-1
-2
- A16
- A17
GRT100
DC
power
supply


Monitoring
jack
A
0V




Current
source
50 or 60Hz
250 or 300Hz


I a
I 2
I 1
Figure 6.5.6 Testing 5F Element (Model 100s, 200s)
The output signal number of the 5F element is as follows:
Element Signal number
5F 123

Set the fifth harmonic restraint setting k5f to 30%.(= default setting)

Press 4 (= Logic circuit) on the "Test" sub-menu screen to display the "Logic circuit"
screen.

Enter a signal number to observe the 5F output at monitoring jack A and press the
ENTER
key.

Set the fundamental frequency current I
1
to 3 times of ik setting. Change the magnitude of
the fifth harmonic current I
5
and measure the value at which the element operates.

Calculate the percentage of the fifth harmonic by I
5
/I
1
when the element operates. Check
that the percentage is within 7% of the k5f setting.