Hioki IM3536 - External Noise; X84; Countermeasures against Incorporation of Noise from the Power Line

Appx.5
Countermeasures Against Incorporation of External Noise
Appx. 4 Countermeasures Against Incorporation of
External Noise
The instrument is designed to be resistant to errors caused by interference from the test cables or
the power supply line. However, if the level of the interference is particularly large, this can cause
measurement errors or faulty operation.
Refer to the examples given below for examples of countermeasures which can be taken against
interference which has caused faulty operation etc.
Countermeasures against incorporation of noise from the power line
You can use the following countermeasures to reduce the effect of noise being incorporated from
the power line.
(1) Ground the protective ground wire.
The instrument is structured so that the ground wire of the power cord can be used as protective
grounding for the instrument. Protective grounding plays an important role in not only the preven-
tion of electrical accidents but also the use of an internal lter to eliminate the incorporation of noise
from the power line. Use the supplied power cord.
(2) Insert a noise lter into the power line.
Connect a commercial plug-in noise lter to the power
outlet and then connect the instrument to the output of
the noise lter in order to suppress the incorporation of
noise from the power line.
Plug-in noise lters are commercially available from vari-
ous specialist manufacturers.
(3) Attach an EMI ferrite-core lter to the power cord.
Pass the power cord through a commercially available
EMI suppression ferrite core and secure the core as
close as possible to the AC power inlet of the instrument
in order to suppress the incorporation of noise from the
power line.
Suppression is even more effective if you also attach an
EMI suppression ferrite core close to the power plug of
the power source.
If a toroidal ferrite core or split ferrite core with a large
enough internal diameter is used, the amount of noise
can be decreased by passing the power cord through
the core several times. EMI ferrite cores and ferrite
beads are commercially available from various specialist
manufacturers.
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