YOKOGAWA CW140, User Manual, Page: 40 / 292

IM CW140-E
3-18
Conductor
cable
Power supply side
(SOURCE)
Load side
(LOAD)
Clamping CT
Joint section
3.7 Performing Measurements with Higher
Precision
To perform measurements with higher precision, use the CW140 under the
following environmental conditions.
Ambient temperature: 23 ±5°C
Ambient humidity: 35 to 75% RH (no condensation)
If installing the CW140 in a location where the ambient humidity is 30% or
less, use such equipment as an anti-static mat to prevent electrostatic
discharge.
If you move the CW140 from an area of low temperature and humidity to an
area of high humidity and temperature or if there is a sudden change in the
ambient temperature, condensation may occur in the meter. If this happens,
let the meter stand still for at least one hour to allow it to adapt to the new
ambient temperature and for condensation to dissolve. Then, begin operating
the meter.
●
Relationship between Clamp and Conductor
1 When performing a
measurement, hold the
clamp-on probe so that the
conductor cable runs
through the center of the
clamping CT.
2 Ensure that the orientation
of the clamp to the
direction of the conductor
cable (from the power
supply to the load) is
correct, as shown on the
right.
3 Ensure that the clamping
CT is properly closed.