Extech Instruments 38394 User manual

User’s Guide
Digital AC/DC Clamp Meter
Model 38394
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Introduction
Congratulations on your purchase of Extech’s 38394 AC/DC Clamp Meter. This clamp
meter measures AC/DC Current to 600A, DC/AC Voltage, Resistance, Frequency,
Diode, and Continuity. This meter is shipped fully tested and calibrated and, with proper
use, will provide years of reliable service.
Safety
Safety Symbols
This symbol, adjacent to another symbol or terminal, indicates the user must
refer to the manual for further information.
This symbol, adjacent to a terminal, indicates that, under normal use, hazardous
voltages may be present
Double insulation
WARNING: This indicates that a potentially hazardous condition which, if not avoided,
could result in death or serious injury.
CAUTION: This indicates that a potentially hazardous condition which, if not avoided,
could result in injury or damage to the meter.
Safety Precautions
WARNING: Improper use of this meter can cause damage, shock, injury or death. Read and
understand this User Guide before operating the meter.
1. Always remove the test leads before making current measurements
2. Always remove the test leads before replacing the batteries
3. Inspect the condition of the clamp jaw, test leads and the meter for any damage
before operating the meter. Repair any damage or replace meter before use
4. Do not exceed the maximum rated input limits
5. Use great care when making measurements, especially when the voltages are
greater than 25VAC rms or 35VDC. These voltages are considered a shock hazard
6. Always discharge capacitors and remove power from the DUT (device under test)
before performing Resistance or Continuity tests
7. Remove the batteries from the meter if the meter is to be stored for long periods
8. Ensure that the selected meter function matches the measurement to be taken
9. If the measured current is higher than the range selected for long periods,
overheating may occur compromising the safety and the operation of the meter’s
internal circuits
10. To avoid discharge risks and erroneous readings, do not measure current on high
voltage conductors (>600V)
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Specifications
Function Range Accuracy
400.0A (AC Amps 0.5 to 400.0A) ±(2% rdg + 5d)
(AC @ 50/60Hz)
AC/DC Current
600A ±(2% rdg + 8d)
AC Voltage 4.000V, 40.00V, 400.0V, 600 V ±(1.2% rdg + 5d)
(AC @ 50/60Hz)
400.0mV ±(0.5% rdg +2d)DC Voltage
4.000V, 40.00V, 400.0V, 600V ±(1.0% rdg + 2d)
400.0Ω, 4.000kΩ, 40.00kΩ, 400.0kΩ±(1% rdg + 5d)
4.000MΩ±(2% rdg + 2d)
Resistance
40.00MΩ±(3.5% rdg + 5d)
Frequency (≥5V) 5.000Hz, 50.00Hz, .500.0Hz, 5.000kHz,
50.00kHz, 100.0kHz ±(1% rdg + 5d)
Continuity Audible tone <10Ωapproximately
Function
Maximum
Input Function
Maximum
Input
V DC/AC 600V DC or
AC Peak Frequency 250V DC or AC peak
Input Limits
A DC/AC 600A DC/AC,
fused Resistance 400V DC or AC peak (<10 seconds)
Conductor Size 1.18" (30mm) maximum
Battery type Two (2) 1.5V AA batteries
Range Selection Automatic ranging
Display 5000 Count LCD
Overload Indication "1" or “-1”
Low Battery Indication Battery icon
Environmental conditions Installation Category III (clamp); Category II (DMM),
Pollution degree 2; Altitude: 2000 meters, Indoor use
only
Operating Temperature/Humidity 32º to 122ºF (0oC to 50oC) / <80% RH
Storage Temperature/Humidity 14º to 140ºF (-10oC to 60oC) / <80% RH
Dimensions 7.0 x 2.5 x 1.3” (178 x 64 x 33mm)
Weight 8.3 oz. (230g)
Zero Adjust REL (Relative) push button
Diode Short/Open, Good/Defect Test
Sample Time 0.35 sec approx.
Input Impedance 10MΩ for ACV & DCV
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Meter Description
Front panel
1. Current Jaws
2. Jaw opening trigger
3. Rotary function switch
4. REL key
5. DATA HOLD key
6. Function key
7. Range key
8. LCD display
9. COM & V/Ωinput jacks
Symbols and Units of Measure
AC Current or Voltage
DC Voltage
•))) Audible Continuity
Diode test
Hold Display Data Hold
Auto Auto Range
Low Battery icon
V Volt (voltage)
Ω Ohm (resistance)
A Ampere (current)
REL Relative Mode
Hz, KHz Hertz, kilohertz (frequency)
WARRANTY
EXTECH INSTRUMENTS CORPORATION (A FLIR COMPANY) warrants this instrument
to be free of defects in parts and workmanship for one year from date of shipment (a six
month limited warranty applies to sensors and cables). If it should become necessary to
return the instrument for service during or beyond the warranty period, contact the
Customer Service Department at [phone] ext. 210 for authorization or visit our
website www.extech.com for contact information. A Return Authorization (RA) number
must be issued before any product is returned to Extech. The sender is responsible for
shipping charges, freight, insurance and proper packaging to prevent damage in transit.
This warranty does not apply to defects resulting from action of the user such as misuse,
improper wiring, operation outside of specification, improper maintenance or repair, or
unauthorized modification. Extech specifically disclaims any implied warranties or
merchantability or fitness for a specific purpose and will not be liable for any direct,
indirect, incidental or consequential damages. Extech's total liability is limited to repair or
replacement of the product. The warranty set forth above is inclusive and no other
warranty, whether written or oral, is expressed or implied.
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OPERATING INSTRUCTIONS
AC/DC Current Measurements
WARNING: Ensure that the test leads are disconnected from
the meter before making current clamp
measurements.
1. Set the Function switch to the 600A range.
2. Press the FUNC key to select AC or DC (the AC/DC icons
will toggle on the LCD with each key press).
3. Press the trigger to open jaw. Fully enclose one conductor
to be measured.
4. The clamp meter will display the reading and automatically
select the proper range
Note: When the meter is set to the DCA mode (clamp jaws
empty), the meter’s display may indicate an offset reading, this
is normal. For best results, use the RELATIVE procedure to
zero the meter before taking DCA measurements.
AC/DC Voltage Measurements
1. Set the Function Switch to the Vposition.
2. Press the FUNC key to select AC or DC Voltage. The meter will display the
selected unit of measure (AC or DC) on the left side of the LCD.
3. Insert the black test lead to the COM input jack and the red test lead to the Vjack.
4. Connect the test leads in PARALLEL with the circuit to be measured.
5. Read the displayed measurement value on the LCD display.
Manual Range
This meter automatic selects the range. However, the range can be manually held and
selected. To manually hold the range, momentarily press the RANGE key the
appropriate number of times to select the desired range. The units of measure and
decimal positioning will change with each press of the RANGE key.
Resistance Measurements
CAUTION: Before taking an in-circuit resistance measurement, remove power from the
circuit under test and discharge all capacitors.
1. Insert the black test lead to the COM input jack and the red test lead to the Ωinput
jack.
2. Set the Function switch to the •))) Ωposition, press the FUNC key if necessary
to display the Ω icon.
3. Connect the test leads to the device under test and read the measured value on
the LCD display.
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Continuity Test
CAUTION: Before taking measurements, remove power from the circuit under test and
discharge all capacitors
1. Insert the black test lead to the COM input jack and the red test lead to the Ωinput
jack.
2. Set the Function switch to the •))) Ωposition.
3. Press the FUNC key until the “•)))” icon appears in the upper right-hand area of the
LCD display.
4. Connect the test lead tips to the device under test.
5. If the resistance is < 10Ω(approx.) a tone will sound.
Frequency Measurements
CAUTION: Before taking an in-circuit measurement, remove power from the circuit
under test and discharge all capacitors.
1. Insert the black test lead to the COM input jack and the red test lead to the VΩ
input jack.
2. Set the Function switch to the Hz position.
3. Connect the test lead tips to the device under test.
4. Read the measured value on the LCD display.
Diode Test
CAUTION: Before taking measurements, remove power from the circuit under test and
discharge all capacitors
1. Insert the black test lead to the COM input jack and the red test lead to the V/Ω
input jack
2. Set the Function switch to the •))) Ωposition
3. Press the FUNC key until the icon appears in the upper right-hand side of the
LCD.
4. Connect the test lead tips to the device to be measured
5. Note the displayed reading
6. Reverse the test lead polarity by swapping the red and black lead connection; note
this reading also.
a. If one reading displays a value and the other reading displays “OL”, the
diode is good
b. If both readings display “OL”, the device is open
c. If both readings are very small or zero, the device is shorted
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
Support line [phone]
Technical Support: Extension 200; E-mail: [email protected]
Repair & Returns: Extension 210; E-mail: [email protected]
Product specifications subject to change without notice
For the latest version of this User Guide, Software updates, and other
up-to-the-minute product information, visit our website: www.extech.com
Extech Instruments Corporation, 285 Bear Hill Road, Waltham, MA 02451
Data Hold
Press the HOLD key momentarily to freeze the present reading on the LCD. Hold will
appear in the display. Press the Hkey again to return to normal operation.
Relative (ZERO) Mode
The Relative mode permits the user to store a reference reading and compare all
subsequent readings to the stored reference value. Subsequent readings will display a
value that is the difference between the actual reading and the stored reference value.
1. Press the REL key when the desired valued is displayed on the meter. This
becomes the stored reference. The REL symbol will appear on the LCD.
2. Take measurements and note that the meter displays the actual reading minus the
reference reading.
3. Press the REL key to return to normal operation. The REL symbol will switch off.
Maintenance
WARNING: To avoid electrical shock or damage to the meter, keep moisture from entering
the meter housing. Also, remove the test leads before opening the meter
housing.
Cleaning
Periodically wipe the case with a damp cloth and mild detergent. Do not use abrasives
or solvents.
Battery Replacement
When the LCD display shows the battery symbol, replace the two ‘AA’ 1.5V batteries.
Accurate readings are possible for a short period of time after the battery symbol
appears, but it is recommended that the batteries be replaced immediately to ensure
accurate results. To replace the batteries, remove the rear battery compartment cover.
Calibration and Repair Services
Extech offers repair and calibration services for the products we sell. Extech also
provides NIST certification for most products. Call the Customer Care Department for
information on calibration services available for this product. Extech recommends that
annual calibrations be performed to verify meter performance and accuracy.
Copyright ©2008 Extech Instruments Corporation (a FLIR company)
All rights reserved including the right of reproduction in whole or in part in any form.
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