Ac Current Measurements - Extech Instruments MA443-NIST User Manual

AC Current Measurements
WARNING: Do not handle the meter above the finger/hand guard barrier.
CAUTION: Observe CAT III 600V with respect to Earth Ground for the Jaw.
Rotate the function switch to the AC Current position ( for MA443 and MA445 or 4 /40
1.
/400 for the MA440). For the MA440 start with the highest range setting (400A) and
step down to lower ranges as needed, especially for signals that are of an unknown range.
2. The A and the AC symbols will appear on the display indicating AC Amperes (Amps). The
display icon AUTO will also appear indicating automatic ranging.
3. Press the jaw trigger to open the clamp jaw.
4. Position the clamp around only one conductor. See Fig. 2 for correct and incorrect clamp
technique.
5. Read the current in the display. The display will indicate the proper decimal point and
value.
NOTES:
To ensure maximum accuracy, place the conductor at the center of the clamp head, otherwise
additional error (± 1.0%) may apply.
Do not release the trigger suddenly; the impact may lead to a change in readings since the Hall
element is sensitive not only to magnetism but also to heat and mechanical stress to some extent.
A
AC
Fig. 2 – Correct and Incorrect ACA Clamping
A
AC
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