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show - - - . This sequential display repeats until a key is
pressed or Auto switch-off operates. For more details of final
display information see Appendix 1. For more detailed
information on PI ratio assessment, see 'Application of
Test Techniques'.
Dielectric Discharge Testing (DD)
This test measures the dielectric absorption of an insulator and
gives an indication of the amount of absorbed dirt and moisture.
Default settings are 500 V and 30 minutes but these may be
changed as required. The default settings will reset if the cursor
is moved away from the 'DD' position. The insulator under test is
charged at 500 V for 30 minutes (to attain a stable condition). A
quick discharge then follows, during which the capacitance is
measured. The remaining current flow is then measured after 1
minute, and the 'DD' value calculated from the formula:
Current after 1 minute (mA)
Test Voltage (V) x Capacitance (F)
1. Using the
Range keys move the right hand cursor to
'DD'.
2. Accept the default time of 30 minutes, or using the
Selector keys move the left hand cursor to the
and then set the test duration using the
Maximum test time is 90 minutes.
3. Accept the default voltage of 500 V, or using the
Selector keys move the left hand cursor to the required test
voltage.
4. Start the test by pressing the red test button for at least one
second.
5. On completion, the 'DD' value is displayed sequentially with
the corresponding insulation resistance, the PI ratio and the
capacitance value. This sequential display repeats until a key
is pressed or Auto switch-of operates. For more details
of final display information see Appendix 1. For more
detailed information on 'DD' value assessment, see
'Application of Test Techniques'.
Step Voltage Testing (SV)
This test is based on the principle that an ideal insulator will
produce identical resistance readings at all voltages while an
insulator which is being over stressed will show lower values at
higher voltages. Operating at either 2,5 kV or 5 kV, the voltage
steps up one fifth every minute for 5 minutes, and successive
measurements are taken.
1.
Using the
2.
Accept the default test time of 5 minutes.
3.
Accept the default voltage of 2500 V, or using the
Selector keys move the left hand cursor to the 5000 V
position.
position
Range keys.
4.
Start the test by pressing the red test button for at least one
second.
5.
On completion, each of the 5 separate results are
sequentially displayed followed by the capacitance value,
where available. This sequential display repeats until a key
is pressed or Auto switch-off operates. For more details of
final display information see Appendix 1.
Range keys move the right hand cursor to 'SV'.
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