99-MAN 100117.v4 06/07
OPERATION
Please make sure that you have already read and fully understand the WARNING section on page 1.
Making Measurements with the AC Current Probe Model JM850A
• Connect the black and red terminals to the Ampere AC range of your DMM or current measuring
instrument. Select the appropriate current range. If the current magnitude is unknown, select the highest
range (3000A AC / 1A AC) on the switch probe located inside the handle. Clamp the probe around the
conductor to be tested, with the arrow pointed toward the load. If the reading is less than 200 mA or 20
mA, select the lower range until you obtain the best resolution. Read the value display on the DMM and
multiply it by the range selected. (If reading = 0.259A on the 1000/1 range, the current flowing through
the probe is 0.259A x 1000 = 259 A AC).
• For best accuracy: carefully center the conductor inside the probe jaw, avoid if possible, the proximity of
other conductors which may create noise.
Tips for Making Precise Measurements
• When using a current probe with a meter, it is important to select the range that provides the best
resolution. Failure to do this may result in measurement errors.
• Make sure that probe jaw mating surfaces are free of dust and contamination. Contaminants cause air
gaps between the jaws, increasing the phase shift between primary and secondary. It is very critical for
power measurement.
MAINTENANCE:
Warning
• For maintenance use only original replacement parts.
• To avoid electrical shock, do not attempt to perform any servicing unless you are qualified to do so.
• To avoid electrical shock and/or damage to the instrument, do not get water or other foreign agents into
the probe.
Maintenance
To ensure optimum performance, it is important to keep the probe jaw mating surfaces clean at all times.
Failure to do so may result in error in readings. The following is the recommended procedure for cleaning
the probe jaws: Use a very fine sand paper (fine 600) to avoid scratching the jaw, then gently clean with a
soft, oil cloth.
REPAIR AND CALIBRATION
You must contact our Service Center for a Customer Service Authorization number (CSA#). This will
ensure that when your instrument arrives, it will be tracked and processed promptly. Please write the CSA#
on the outside of the shipping container. If the instrument is returned for calibration, we need to know if you
want a standard calibration, or a calibration traceable to N.I.S.T. (includes calibration certificate plus
recorded calibration data).
Chauvin Arnoux
®
, Inc. d.b.a. AEMC
®
Instruments
15 Faraday Drive
•
Dover, NH 03820 USA
Tel:
(800) 945-2362 (Ext. 360) or (603) 749-6434 (Ext. 360)
Fax:
(603) 742-2346 or (603) 749-6309
[email protected]
(Or contact your authorized distributor)
Costs for repair, standard calibration, and calibration traceable to N.I.S.T. are available.
NOTE: All customers must obtain a CSA# before returning any instrument.
TECHNICAL AND SALES ASSISTANCE
If you are experiencing any technical problems, or require any assistance with the proper use or
application of this instrument, please call our technical hotline:
(800) 343-1391 • (508) 698-2115 • Fax (508) 698-2118
Chauvin Arnoux
®
, Inc. d.b.a. AEMC
®
Instruments
www.aemc.com
AC Current Probe
Model JM850A
User Manual
DESCRIPTION
The JM850A (Catalog # 2110.87) is designed for use in industrial environments. The “squared” jaws
permit multiple conductor or bus bar positioning. The current output makes it the perfect tool for
measurement with DMMs, recorders, power and harmonic meters. Three ranges allow you to obtain the
best resolution even on low current measurement. The Model JM850A is compatible with any AC
ammeter, multimeter, or other current measuring instrument with an input impedance lower than 2.5
Ω
. To
achieve the stated accuracy, use the JM850A with an Ammeter having an accuracy of 0.75% or better.
WARNING
These safety warnings are provided to ensure the safety of personnel and proper operation of the
instrument.
• Read the instruction manual completely and follow all the safety information before attempting
to use or service this instrument.
• Use caution on any circuit: Potentially high voltages and currents may be present and may
pose a shock hazard.
• Read the Safety Specifications section prior to using the current probe. Never exceed the
maximum voltage ratings given.
• Safety is the responsibility of the operator.
• ALWAYS connect the current probe to the display device before clamping the probe onto the
sample being tested.
• ALWAYS inspect the instrument, probe, probe cable, and output terminals prior to use.
Replace any defective parts immediately.
• NEVER use the current probe on electrical conductors rated above 600 V in overvoltage
category III (CAT III). Use extreme caution when clamping around bare conductors or bus bars.
INTERNATIONAL ELECTRICAL SYMBOLS
This symbol signifies that the current probe is protected by double or reinforced insulation. Use
only factory specified replacement parts when servicing the instrument.
This symbol signifies CAUTION! and requests that the user refer to the user manual before
using the instrument.
This is a type A current sensor. This symbol signifies that application around and removal
from HAZARDOUS LIVE conductors is permitted.
DEFINITION OF MEASUREMENT CATEGORIES
Cat. I:
For measurements on circuits not directly connected to the AC supply wall outlet such as
protected secondaries, signal level, and limited energy circuits.
Cat. II:
For measurements performed on circuits directly connected to the electrical distribution system.
Examples are measurements on household appliances or portable tools.
Cat. III:
For measurements performed in the building installation at the distribution level such as on
hardwired equipment in fixed installation and circuit breakers.
Cat. IV:
For measurements performed at the primary electrical supply (<1000V) such as on primary
overcurrent protection devices, ripple control units, or meters.
RECEIVING YOUR SHIPMENT
Upon receiving your shipment, make sure that the contents are consistent with the packing list. Notify
your distributor of any missing items. If the equipment appears to be damaged, file a claim immediately
with the carrier and notify your distributor at once, giving a detailed description of any damage.
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.com
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