3
connecting line.
5.7 Don't use or have the storage in the place of sun
、
high
temperature
、
humidity etc.
5.8 The short circuit time of the testing end should be less than
60s.
5.9 The continuous testing time should be less than 3 hours one
time.
6.Work theory
The high voltage part of the instrument is applied with the
Pulse Width Modulate(PWM), via the inner double voltage output
cathode DC high voltage, with the characteristic of energy saving,
good voltage linearity, stabilization and small ripple coefficient.
The high voltage produced by the instrument line terminal
goes to the instrument earth terminal via the load resistance Rx,
then transformation via V/I to display the digit.
7.Testing
Danger
●
Before testing, please sure there is no charge existing in the
tested circuitry that the high voltage instrument is connected
with.
●
Please put on a pair of the high voltage insulation gloves.
●
If the battery cover is open, please don't carry on any
measurement.
7.1 testing end connection
Insert the plug of the testing line with the testing stick into the L
terminal socket of the instrument, then insert the plug of the testing
line with the testing clip to the E terminal socket of the instrument
and connect well separately.
7.2 testing connection
The connection of terminal E plug(black test lead with the big
testing clip) is for the Earth, connect the testing clip to one side of
the item ; the connection of terminal L plug(red test lead) is
circuitry line, can connect the testing clip to the other side of the
item ; the connection of terminal G plug is shielding line, and is
connected to the surface of the tested object to avoid the surface
leakiness which will influence the testing impedance. Connect the
testing clip to one end of the tested object, and the small clip of the
test lead to the surface of the tested object to avoid the current
leakiness.(Picture A and B)
7.3 Rated voltage selection
Select the rated voltage according to the test requirements:
HDT20A can choose 250V 500V 1000V
HDT20B can choose 500V 1000V 2500 V
7.4 Testing operation
Please pay attention to safety operation:
Connect the test lead of the test stick to one end of the tested
object, press down the high voltage startup button [TEST], then the
red indication light HV ON turns on to show that the high voltage
output gets through. When the high voltage indicator is on, it
means the instrument work normally. If it is off, it shows maybe
the battery is low voltage or battery connection is abnormally.
When the measurement is begun, there is reading on the meter
header which is the insulation resistance value of the tested object
under the current voltage.
For the HDT20A, when the test value is less than 200M
Ω
,suggest pressing the
“
”
button, using 200M
Ω
range
can make the readings more accurate. For the HDT20B, when the
test value is less than 2G
Ω
,suggest pressing the
“
”
button, using 2G
Ω
range can make the readings more accurate.
When the testing is out of range (the digit only display
“
1
”
), you
can check the
“
”
or
“
”
button is in the raised
state or not, if not you can press it to let it in the raised state; if yes
show the measured value of insulation resistance measurement is
beyond the scope of this instrument, pls consider using a higher
resistance of tester.
If you need more convenient readings, you can press the
“
HOLD, LIGHT
”
button, the display digit will be locked and
backlight is on for easy reading. Press that button again to restore
the normal measurement state and the backlight is off.
7.5 Backlight
Press button, backlight is on; press the button again, the
backlight is off.
7.6 Power off
After finish the measurement, press down the high voltage
button [TEST], HV ON red indicator turns off slowly, showing the
high voltage output has disconnected. Set the switch to the position
[OFF], there is no display on the LCD. For the capacitive load, you
should completely release the residual charge in the tested object to
avoid the residual charge release electricity to injury people.
8. AC Voltage Test
8.1 Using the rotary switch select the
“
ACV
”
position
8.2 Insert the red test lead into the
“
ACV
”
jack, insert the black
test lead into the
“
G
”
input jack
8.3 Contact the two test leads with the both ends of the voltage
to be measured, then the digital display show the AC voltage in
volt.
Note:
1.
The measured voltage can
’
t exceed 750V AC RMS, the
frequency of the ACV is 40Hz to 400Hz. If exceed this
frequency range, the data errors will exceed the technical
specifications of this instrument.
2.
For the earth voltage to be measured at the both ends can
’
t
exceed 750V AC RMS, otherwise will meet the danger of
electric shock.
3.
AC voltage test, don
’
t need to transfer the high voltage
and range, so at that time the
“
TEST
”
and
“
”
button are disabled.
9.Battery replacement
If there is the symbol " " on the LCD, it indicates low battery,
please replace the battery.
Before replacing the battery, please sure the testing connection
has been disconnected and power is cut off.
