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WARNING!: failure to observe test connection precautions may result in severe injury or death to the operator. The
display will prompt the user to press the HV enable key as follows:
HIGH VOLTAGE ENABLE
REQUIRED
Once the test connections have been verified, press the HV enable button. After pressing the high voltage enable key the final
prompt is:
PRESS ENTER TO
START TEST
Upon pressing the enter key the 944i will sound a number of warning beeps while flashing the HV enable indicator. If the user
has enabled the auto-ground test feature of the 944i, the unit will automatically check the chassis of the DUT for earth ground
continuity before applying high voltage to the DUT.
Whenever any voltage greater than 80 volts is applied to the output terminals, the high voltage present indicator will automatically
illuminate. The starting point for all direct high voltage tests is at 100V. The test display is arranged with the top row indicating
the output voltage in both digital read-out and bar graph formats. The multi-segment bar graph represents the proportion of output
voltage relative to the preset voltage limit. For example, if the output setting was 500 volts and the preset voltage limit was 2500
volts approximately 20% of the bar graph segments will be illuminated.
Adjacent to the bar graph is a digital display of the output voltage setting. The display is a four-digit display with a resolution of
one volt. The digit that is blinking is the digit that is presently subject to modification by the up/down cursors. To increase the
output voltage, press the up arrow. To decrease the output, press the down arrow. To move the blinking digit to the left or right,
use the left/right cursors.
If at any time during direct output control the preset maximum current limit is exceeded, the
test is automatically aborted and a
maximum current exceeded message will be displayed. When the user has completed direct mode testing, press the High Voltage
Disable/Stop key to remove the high voltage output. ALWAYS verify that the high voltage present indicator has extinguished
prior to handling the test leads.
.........................................................................................
AC Dielectric Strength Function
AC dielectric strength testing is performed to evaluate a materials ability to resist the flow of alternating current in the presence of
high voltage. The AC dielectric strength test is also commonly referred to as: AC Hipot, AC Voltage Breakdown and AC Voltage
Withstand.
To begin an AC dielectric test press VAC. The 944i will respond with the following message:
AC DIELECTRIC TEST
DIRECT AUTOMATIC
This message confirms that the AC function has been selected and offers two different operating modes. By using the left/right
cursor arrows, one can alternatively highlight either Direct mode or Automatic mode.
Direct mode permits manual operation and is highlighted when the Direct/Automatic menu pops up. To select DIRECT mode,
simply press enter. The following prompt will appear:
ENTER MAX VOLTAGE
1000 VOLTS
This prompt allows the operator to set a maximum test voltage. This limit prevents the user from inadvertently exceeding the
intended range of output voltage. The 1000 VAC shown is the default limit. To enter another limit, simply press the number keys
for the desired value. The range of limits for the VAC function may be as low as 100 VAC or as high as 5000 VAC. Once the
desired voltage limit is displayed, press enter to advance to the next step.
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