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The following shows the case when testing DSEF1F.
• Select "Logic circuit" on the "Test menu" screen to display the "Logic circuit" screen.
• Enter the signal number to be observed at monitoring jack A as shown in Section 6.5.1.
• Apply the rated voltage VT (= V 0 ) and single-phase test current IT (= I se ).
Set IT to lag V 0 by DSE characteristic angle DSE θ . (The default setting of DSE θ is 0°.)
•
Changing the magnitude of IT while retaining the phase angle with the voltages, and measure
the current at which the element operates. Check that the measured current magnitude is
within ± 5% of the current setting.
6.5.1.4
Thermal overload element THM-A and THM-T
The testing circuit is same as the circuit shown in Figure 6.5.2.
The output signal of testing element is assigned to the monitoring jack A.
The output signal numbers of the elements are as follows:
To test easily the thermal overload element, the scheme switch [THMRST] in the "Switch" screen
on the "Test" menu is used.
• Set the scheme switch [THMRST] to "ON".
• Enter the signal number to observe the operation at the monitoring jack A as shown in
Section 6.5.1.
• Apply a test current and measure the operating time. The magnitude of the test current
should be between 1.2 × I s to 10 × I s , where I s is the current setting.
CAUTION
After the setting of a test current, apply the test current after checking that the THM% has
become 0 on the "Metering" screen.
• Calculate the theoretical operating time using the characteristic equations shown in Section
2.1.4. Check that the measured operating time is within 5%.
Element
Signal No.
THM-A
177
176
THM-T
⎯
⎯
260
6 F 2 S 0 8 4 2
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