KYORITSU 4202 - Manual (Page 12)

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7. Measuring method
# DANGER
Never make measurement on a circuit in which the electrical potential
exceeds AC300V.
Transformer jaws are made of metal and their tips are not completely
insulated. Be especially careful about the possible shorting where the
equipment under test has exposed metal parts.
Never make measurement with the Battery cover removed.
Do not measure a current over 30A. Transformer jaws may heat to cause
a fire or deformation of molding parts, which will degrade insulation. When
clamping the conductors on which over 30A flowing and " " is displayed
on the LCD, stop measurement immediately and take off the instrument
from the conductor under test.
# CAUTION
Take sufficient care not to apply shock, vibration or excessive force to the
jaw tips.
Otherwise, precisely adjusted Transformer jaws will be damaged.
This instrument performs self-calibration for about 3 seconds when
it is turned on. ("
" is displayed on the LCD.) Do not clamp onto
any conductor or open the jaws in this period. Otherwise, inaccurate
measurement may occur.
When foreign substances are stuck in the jaw tips or they are not properly
engaged, the Transformer jaws do not fully close. In such a case, do not
release the jaw trigger abruptly or attempt to close the Transformer jaws by
applying external force. Make sure that the jaws close by themselves after
removing the foreign substance or making them free to move.
The size of a conductor can be tested is 30mm in diameter. Accurate
measurement cannot be made on a conductor larger than this, because the
Transformer jaws cannot fully close.
Never attempt to apply excessive force to close the jaws.
When measuring large current, the Transformer jaws may buzz. This has no
effect on the instrument's performance or safety.
Sensitive Transformer jaws are used for this instrument. Because of the
characteristics of Transformer jaws, which can be opened and closed,
it is impossible to eliminate the interference of external magnetic field
completely. If there are something, which generating large magnetic field, at
a nearby site, current value can be displayed (“0” may not be displayed)
before clamping on the conductor. For such a case, please use the
instrument at a location far from the thing, which generating magnetic field.
Following are the typical things generating magnetic field.
* Conductor fed large current
* Motor
* Equipment which has magnet
* Integrating wattmeter