Extech 382075 Operating Manual
User's Manual
Model 382075
3φ/1φ Power Clamp-on Meter
Introduction
Congratulations on your purchase of the Extech Model 382075 Auto Range Power Clamp-On Meter.
Careful use of this device, will provide years of reliable service.
Meter Functional Description
1. Transformer Jaw
Used to sense current signal. To measure current or power,
the conductor under test must be fully enclosed by the jaw.
2. Transformer Trigger
Press to open the jaw.
3. Data Hold Button
Press to freeze most recent reading on the LCD. Press
again to release.
4. Function Select and On/Off Switch
Select desired function, such as KW, V, A, KVA, or 3φ.
5. LCD Display
4-digit (9999 count) display with function symbols, units,
decimal point, low battery icon, and zero indication.
6. Units Symbols
Once a function is selected, the corresponding unit (KW, V,
A, Phase, KVA, or 3φ) will be displayed.
7. 3φ3W and 3φ4W Select Button
If the 3φ system is not a balanced system, users can press
this button to select 3φ3W, 3φ4W or a balanced system.
Once the button is pressed, the LCD displays 3φ3W or
3φ4W depending on the function selected.
8. Read/Next Button
• When the rotary switch is set to the 3φ function, the READ/NEXT button is used as a NEXT button.
In the 3φ balanced mode, pressing the NEXT button will display W+PF, KVA+KVAR, or V+A data.
• In the 3φ3W mode, pressing the NEXT button stores the measured values W
After two values are measured and stored, the meter adds the two values, displays the result with
the symbol W
to represent W
RST
. To start another W
3φ3W
again.
• In the 3φ4W system mode, press the NEXT button to store the measured values W
W
. After three values are measured and stored, the meter adds the three values, displays the
T(L3)
result with the symbol W
to represent W
RST
. To start another W
3φ4W
NEXT button again.
• If the rotary switch is not set to the 3φ function, the READ/NEXT button is used as a READ button.
Stored data in memory (saved by pressing the REC button) can be read by pressing READ.
9. & 10. V and COM Input Terminals
Used as positive and negative (common) inputs for voltage measurements.
11. DC A/W ZERO button
Press this button once to zero the Amp or Watt display. While the meter is zeroing, the word ZERO
appears the LCD.
12. REC button
Press the REC button to store up to 4 data points in meter memory.
Figure 1
and W
RS(L1L2)
measurement, press the NEXT button
3φ3W
R(L1)
measurement, press the
3φ4W
, W
TS(L3L2)
S(L2)
and
.
Operating Instructions
NOTE: Ensure that the jaws are clear of any conductors before applying power to the meter. The
meter performs an auto zero upon power-up to null any residual magnetism. If this is done with a
conductor inside the jaw area, the auto zero function will cause subsequent measurements to be
inaccurate.
DC/AC 1φ2W Power (W) and Power Factor (PF) measurements
1. Apply power to the meter with the jaws clear of
any conductors.
2. Set the rotary switch to the Watts function
(KW).
3. If the watt reading is not zero, press the
DCA/DCW ZERO button once to zero it.
4. Insert the test leads into the input terminals.
5. Connect the COM (black) terminal to the
neutral line.
6. Connect the V (red) terminal to the power line.
7. Clamp on to the line where the V (red) terminal
is connected. The power clamp will
automatically select the proper measurement
range. Read the Watt and PF (Power Factor)
values displayed on the LCD.
NOTE: The "+" sign printed on jaw must face the power source for accurate measurements.
1 Phase 2 Wire
Current >
1 Phase
Load
Figure 2
AC/DC Voltage Measurements
Voltage (V) and Frequency (Hz) Dual Display
WARNING: Maximum input voltages: 1000VDC and 750VAC. Do not attempt to measure voltage
that exceeds these limits.
1. Set the rotary switch to the Voltage position (V).
2. Insert the test leads into the input terminals.
3. Connect the test leads in PARALLEL with the circuit to be
measured.
4. The power clamp will automatically select the proper range.
5. Read the voltage and Frequency values displayed on the LCD.
NOTE: The sensitivity for voltage/frequency measurements
is 1V, and the frequency range is 10 - 400Hz. If the
frequency is < 10 Hz, the LCD will indicate 0 Hz. If the
frequency is > 400 Hz, LCD will show OL.
Voltage(V) / Current (A) Dual Display
Follow the instructions in the section entitled "3φ Balanced Power
Measurements" to monitor V and A simultaneously.
Figure 3
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".
Figure 4
Voltage (V) and Current (A) Dual Display
Follow the instructions in the section entitled "3φ Balanced
Power Measurements" to monitor Voltage and Current simultaneously.
DC/AC 1φ2W 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:
KVAR = KVA * sin φ
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.
1 Phase 2 Wire Current >
Figure 5
1 Phase
Load
V
A
-23.8
XL
o
NOTE: Zero the current (A) reading before measuring to avoid incorrect Phase Angle readings.
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