YOKOGAWA EY200, User Manual

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<2> Earth Voltage Measurement (Series interference voltage): ~V
Set the range switch to Earth voltage (˜V) position in the
condition of <1>.
Earth voltage will be indicated on the display. Make sure
that the voltage is 3V or less.
When the display reads more than 3V, it may result in
excessive errors in earth resistance measurement. To avoid
this, make measurement after reducing the voltage by
turning off the power supply of the equipment under test etc.
<3> Earth resistance (
Ω
) Measurement: (Precise Measurement)
Set the range switch to 2000Ω position and press the test
button (Ω measurement.).
LED remains illuminated during testing. Turn the range
switch to 200Ω and 20Ω when the earth resistance is low.
This indicated value is the earth resistance of the earthed
equipment under test.
<Note>
• If the auxiliary earth resistance of auxiliary earth spike
C is too high to make measurement, the display reads
' . . . '. Recheck the connection of test leads and the earth
resistance of auxiliary earth spike.
#
CAUTION
• If measurement is made with the probes twisted or in touch
with each other, the reading of the instrument may be affected
by induction. When connecting the probes, make sure that they
are separated.
• If earth resistance of auxiliary earth spikes is too large, it may
result in inaccurate measurement.
Make sure to stick the auxiliary earth spike P and C into
the moist part of the earth carefully, and ensure sufficient
connections between the respective connections.
6-3 Simplified Measurement (Using 2P Test Leads)
Use this method when the earth spike cannot be stuck. In this
method, an existing earth electrode with a low earth resistance,
such as a metal water pipe, a common earth of a commercial
power supply and an earth terminal of a building, can be used
with two-pole (wire) method (E,P).
Use the simplified measurement probe attached which has a
convenient structure that both the safety alligator clip and the
test bar are available.