<6. Maintenance>
6-4
IM 21B03D01-01E
Inspection after Amplifier Replacement
After replacing the amplifier, perform the insulation
resistance test and withstand voltage test. Be
sure to perform them according to the following
procedure, referring to the corresponding tester
instruction manuals.
CAUTION
• Overvoltage of the test voltage that is so
small that it does not cause an dielectric
breakdown may in fact deteriorate insulation
and lower the safety performance; to prevent
this it is recommended that the amount of
testing be kept to a minimum.
• The voltage for the insulation resistance test
must be 500V DC or lower, and the voltage
for the withstand voltage test must be 500V
AC or lower. Failure to heed these guidelines
may cause faulty operation.
• Where a built-in arrester is provided (suffix
code: /A), the voltage for the insulation
resistance test must be 100V DC or lower,
and the voltage for the withstand voltage test
must be 100V AC or lower. Failure to heed
these guidelines may cause faulty operation.
Follow the steps below to perform the test, the
wiring of the communication line must be removed
before initiating testing.
Insulation resistance test procedure
1. Lay transition wiring between the + terminal and
the - terminal.
2. Connect the insulation resistance meter (with
the power turned OFF) between the transition
wiring of Step 1 above and ground terminal.
The polarity of the input terminals must be
positive and that of the ground must be
negative.
3. Turn the power of the insulation resistance
meter ON and measure the insulation
resistance. The duration of the applied voltage
must be the period during which 100 MΩ
or more is confirmed (or 20 MΩ if the unit is
equipped with a built-in arrester).
4. Upon completion of the test, remove the
insulation resistance meter, connect a 100
kΩ resistor between the transition wiring, and
allow the electricity to discharge. Do not touch
the terminal with your bare hands while the
electricity is discharging for more than one
second.
Withstand voltage test procedure
Testing between the input terminals and the
grounding terminal
1. Lay the transition wiring between the + terminal
and the - terminal, and connect the withstand
voltage tester (with the power turned OFF)
between the transition wiring and the grounding
terminal.
Connect the grounding side of the withstand
voltage tester to the grounding terminal.
2. After setting the current limit value of the
withstand voltage tester to 10 mA, turn
the power ON, and gradually increase the
impressed voltage from 0 V to the specified
value.
3. The voltage at the specified value must remain
for a duration of one minute.
4. Upon completion of the test, carefully reduce
the voltage so that no voltage surge occurs.
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