Ac/Dc Current Measurements - Extech Instruments 382075 User Manual

AC/DC Current Measurements

Current (A) + Frequency (Hz) Dual Display
WARNING:
1. When applying power to the meter, make sure the clamp jaws are not near a conductor.
2. Make sure that test leads are disconnected from the meter during current measurements.
1. Set the rotary switch to the Amps position (A).
2. Push and hold the DCA/DCW ZERO button to zero the reading.
3. Press the trigger to open the jaw and fully enclose the conductor
to be measured. The Jaws must be completely closed to make a
measurement (see Fig.4).
4. Read the current/frequency values on the LCD.
NOTE: The sensitivity for current/frequency measurement is
5A, and the frequency range is 10 - 400Hz. If the frequency is
< 10 Hz, the LCD will display 0 Hz. If the frequency is > 400
Hz, LCD will display "OL".
Voltage (V) and Current (A) Dual Display
Follow the instructions in the section entitled "3φ Balanced
Power Measurements" to monitor Voltage and Current simultaneously.
φ
DC/AC 1 2W Apparent/Reactive Power Measurements (KVA+KVAR)
NOTE: Before taking any measurements, zero the current (A) reading and set the rotary switch to
the KVA position.
Follow the steps listed in section entitled DC+AC 1φ2W Power (W) and Power Factor (PF)
measurement for these measurements. KVAR is a calculated value, and its accuracy greatly depends
on the accuracy of the V, A, and KW readings. To obtain a more accurate KVAR value when PF is
greater than 0.91 (φ < 25°), measure the phase angle and obtain the KVAR from the following equation
for a pure sine wave:
Phase Angle Measurements
1. Set the rotary switch to the A position. If the current reading is not zero, press the DCA
ZERO button.
2. Set the rotary switch to the Phase position.
3. Insert the test leads into the input jacks.
4. Connect the test lead inserted in the COM (black)
terminal to the reference line.
5. Connect the test lead connected to the V (red)
terminal to the voltage signal under test.
6. Clamp on to the wire where the V (red) terminal is
connected (see Fig.5).
7. If current signal is detected from the jaws, the
phase angle will be displayed in degrees on the
LCD together with the frequency of the voltage.
8. If current is not detected, only the frequency of the
voltage will be displayed while the phase angle
display will be left blank.
NOTE: Zero the current (A) reading before measuring to avoid incorrect Phase Angle readings.
KVAR = KVA * sin φ
1 Phase 2 Wire
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Figure 4
Current >
1 Phase
Load
V
-23.8
A
Figure 5
XL
o