AEMC JM850A Operating Manual

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.

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 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.

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.

PACKAGING

The shipping container includes the probe, this instruction manual and a product registration card.
You can now register online at www.aemc.com.

INSTRUMENT COMPATIBILITY

The Model JM850A is compatible with any AC Ammeter, multimeter, or other current measuring
instrument with an input impedance lower than 2.5Ω. To achieve the stated accuracy, use the JM850A
with an Ammeter having an accuracy of 0.75% or better.

INSTRUMENTS

fi

Ø=2.52" (64 mm)

Cable max.

1.97 x 5.31" (50 x 135 mm) or

2.52 x 3.94" (64 x 100 mm)
Bus Bar max.

12.40"

(315 mm)

P1 P2

4.72"

(120 mm)

ELECTRICAL SPECIFICATIONS

Current Range:

1 to 1000A AC continuous cycle
1 to 2000A AC continuous cycle
1 to 2400A AC continuous cycle for the
full temperature range
(3000A if temperature is < 35°C or 95°F)

Transformation Ratio:

1000:1, 2000:1, 3000:1

Output Signal:

1 mA AC/A AC (1A at 1000A)

0.5 mA AC/A AC (1A at 2000A)

0.333 mA AC/A AC (1A at 3000A)

1.89"

(48 mm)

Red Black

S2S1

Accuracy and Phase Shift*:
1000A RANGE

Primary current 50A 200A 1000A

Accuracy % 3% 1.5% 1%

Phase shift 3° 1.5° 1°

Load Impedance: 2.5Ω
Overload: 1400A for 10 mn
Ampere Second Product: 25 A.s
Accuracy: Per IEC 185-26-27

Class 1 (2.5 VA) from 48 to 1000 Hz

2000A RANGE

Primary current 100A 400A 2000A

Accuracy % 1.5% 0.75% 0.5%

Phase shift 1.5° 0.75° 0.5°

Load Impedance: 5Ω
Overload: 2400A for 10 mn
Ampere Second Product: 60 A.s
Accuracy: Per IEC 185-26-27

Class 0.5 (5 VA) from 48 to 1000 Hz

3000A RANGE

Primary current 150A 600A 3000A

Accuracy % 1.5% 0.75% 0.5%

Phase shift 1.5° 0.75° 0.5°

Load Impedance: 10Ω
Overload: 3400A for 10 mn
Ampere Second Product: 90 A.s
Accuracy: Per IEC 185-26-27

Class 0.5 (10 VA) from 48 to 1000 Hz

(*Reference conditions: 23°C±3°K, 20 to 85%
RH, 45 to 65 Hz, external magnetic field < 40
A/m, no DC component, no external current
carrying conductor, test sample centered.)

Frequency Range: 30 to 1000Hz; current
derating above 1000Hz for continuous use

Load Impedance: ≤ 10Ω
Working Voltage: 600V AC
Common Mode Voltage: 600V AC
Open Secondary Voltage:

42V max. by limiting circuit

Influence of Adjacent Conductor:

0.005A/A AC

Influence of Conductor in Jaw Opening:

1.5% ± 0.2A on 1000:1 range
1% ± 0.2A on 2000:1 range
1% ± 0.2A on 3000:1 range

MECHANICAL SPECIFICATIONS

Operating Temp.: 14° to 122°F (-10° to 50°C)
Storage Temp.: -13° to 176°F (-25° to 80°C)
Influence of Temperature: < 0.1% per 10°K
Jaw Opening: 3.54" (90 mm)

Maximum Conductor Size:

Cable: 2.52" ∅ max. (64mm)
Bus bar: 1.97 x 5.31" (50 x 135 mm)

2.52 x 3.94" (64 x 100 mm)

Envelope Protection: IP 20 (IEC 529)
Drop Test: 1 m (IEC 68-2-32)
Mechanical Shock: 100 g (IEC 68-2-27)
Vibration: 10/55/10 Hz, 0.15 mm (IEC 68-2-6)
Polycarbonate Material:

Handles: 10% fiberglass charged
polycarbonate UL 94 V0

Jaws: ABS UL 94 V2

Dimensions:

4.72 x 12.40 x 1.9" (120 x 315 x 48 mm)

Weight: 2.65 lbs. (1200 g)
Colors: Dark gray handles with red jaws
Output:

Two standard safety banana jacks (4mm)

SAFETY SPECIFICATIONS

Electrical:

Double insulation or reinforced insulation
between the primary or secondary and the
outer case of the handle upon IEC 1010.

Common Mode Voltage:

- 600 V Category III, Pollution: 2.

- 300 V Category IV, Pollution: 2.

Electromagnetic Compatibility:
(CE Mark)

EN 50081-1 Class B
EN 50082-2 Electrostatic discharge
IEC 1000-4-2
Radiated field IEC 1000-4-3
Fast transients IEC 1000-4-4
Magnetic field at 50/60 Hz IEC 1000-4-8

ORDERING INFORMATION

Current Probe JM850A..................Cat #2110.87

Accessories:

Leads, set of 2, 5 ft. safety (1000V).Cat #2111.29

Lead No. 211 for Probe 5A Series

(5 ft. rated 250V)..............................Cat #2950.06

Pair, safety current leads

(5 ft. retractable, rated 250V)........... Cat #100.319

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: [phone] (Ext. 360) or [phone] (Ext. 360)

Fax: [phone] or [phone]
[e-mail]
(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:

[phone] • [phone] • Fax [phone]

Chauvin Arnoux

[e-mail]

®

, Inc. d.b.a. AEMC® Instruments

www.aemc.com

99-MAN 100104.v3 11/03