― 11 ―
Note:
¡
Some circuits have an unstable insulation resistance, which causes
the reading to vary during measurement.
¡
The instrument may generate a high pitch tone during
measurement. This is not a failure.
¡
If the circuit under test has a large capacitive load, it may take
some time before the final reading can be obtained.
¡
On insulation resistance range, DC voltage is supplied through
earth and Line probes, with earth probe having positive polarity.
Earth probe should be connected to the earth conductor in the circuit
under test. Such connection is known to be more suitable for
insulation tests since an insulation resistance value measured with
the positive side connected to earth is typically less than that taken
through the reversed connection.
DANGER
¡
When the Test button or Remote control switch is pressed with the
Range selector switch set to an insulation resistance range
position, take care not to touch the tip of the test probe or the
circuit under test where a high voltage is present in order to avoid
possible shock hazard.
¡
Do not make measurement with the Battery cover removed.
CAUTION
¡
Ensure that the circuit under test is de-energized prior to any
insulation testing.
(1) Check the maximum voltage that may be applied to the circuit
under test. Set the Range selector switch to a desired insulation
resistance range. Keep the Safety key pressed down when turning
the Range selector switch to 500V and 1000V position. (Only the
500V range is available on KEW3022.) The message "no" is
displayed on the LCD when turning the Range selector switch
without pressing the Safety key.
¡
Buzzer sounds when the Safety key is pressed down.
Keep the Safety key pressed down when switching 500V and 1000V.
Fig. 5
