Megger PPX30, Руководство пользователя, Страница: 61 / 84

NOTE: The HiPot overcurrent trip indicator detects any arc-over in the insulation and puts an immediate stop to
testing. The overcurrent trip will remove the high voltage from the test leads, stop the test, and display a HIPOT
TRIP message on the front panel display. If you release the Test button, it resets the trip circuitry, removes the HIPOT
TRIP message, and readies the tester for a new test.
Interrupt this test by releasing the Test button any time you observe a fast and sharp rise in current.
The overcurrent trip levels that activate the HiPot trip on the power pack are 12 times the µA/division setting on the
PPX. For example, on the 10 µA/division setting, overcurrent trip will occur at 120 µA.
5. If a HiPot trip occurs, a message dialog like the one shown below will also appear. Release the Test (PTT) button
to reset the overcurrent trip
Fig 49: Overcurrent message dialog.
Table 18: Overcurrent trip levels for DC HiPot testing.
PPX Function Selector Switch Setting Overcurrent Trip Occurs at
1 µA/div 12 µA
10 µA/div 120 µA
100 µA/div 1200 µA
6. Adjust the
Function Selector
switch on the power pack to select a practical µA/div setting for monitoring the
leakage current (for example, if the signal is < 50 µA, switch to 10 µA/division; < 5 µA switch to 1 µA/division).
Typically, the leakage current should rise initially then fall and remain at a constant level. This level is the measure
of the leakage current.
7. Set the power pack Test Select switch to HiPot .
NOTICE: To avoid damage to the unit under test, do not change either the Function Selector switch or the Test
Select switch out of HiPot mode during the performance of a HiPot test.
You must predetermine the necessary values to input during the test before the test start (refer to the
“Recommended Test Voltages” section in “Appendix C— DC and Surge Tests Voltages”).
For this example, let’s assume that we are testing a 6600-volt motor. The value for the DC HiPot would be:
ƒ 2 x (VLL) + 1,000 = 14,200 volts for this example. 14,000 volts is a practical level.
Typical guidelines for DC voltages applied during insulation resistance (IR) testing are 3300 volts for this example
motor.
If a Step Voltage test is run, the increments for each step are based on a starting voltage of 3300 (level for running
Megohm, IR, and DA/PI tests).
Two more increments of 3300 volts each will be used for each step (6600 and 9900).
The final step will increment 4100 volts (14000) and will be run as a DC HiPot test.
Using Power Packs with Baker DX Testers
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