Amprobe CT238A User Manual [en, fr, de]

CT238A

AC/DC Current Probe

User Manual

•Mode d’emploi

•Bedienungshandbuch

CT238A

AC/DC Current Probe

User Manual

• Mode d’emploi

• Bedienungshandbuch

PN 1566235
March 2007
©2007 Amprobe Test Tools.
All rights reserved.

CT238A

AC/DC Current Probe

User Manual

English

Limited Warranty and Limitation of Liability
Your Amprobe product will be free from defects in material and

workmanship for 1 year from the date of purchase. This warranty does not
cover fuses, disposable batteries or damage from accident, neglect, misuse,
alteration, contamination, or abnormal conditions of operation or handling.
Resellers are not authorized to extend any other warranty on Amprobe’s
behalf. To obtain service during the warranty period, return the product
with proof of purchase to an authorized Amprobe Test Tools Service Center
or to an Amprobe dealer or distributor. See Repair Section for details. THIS
WARRANTY IS YOUR ONLY REMEDY. ALL OTHER WARRANTIES - WHETHER
EXPRESS, IMPLIED OR STAUTORY - INCLUDING IMPLIED WARRANTIES OF
FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY, ARE HEREBY
DISCLAIMED. MANUFACTURER SHALL NOT BE LIABLE FOR ANY SPECIAL,
INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES, ARISING
FROM ANY CAUSE OR THEORY. Since some states or countries do not
allow the exclusion or limitation of an implied warranty or of incidental or
consequential damages, this limitation of liability may not apply to you.

AC/DC Current Probe

Contents

Warnings and Precautions ...................................................................................... 1

Symbols .................................................................................................................... 1

Introduction .............................................................................................................1

Specifications ........................................................................................................... 2

Electrical data .......................................................................................................2

General data ......................................................................................................... 2

Operating Instructions ............................................................................................ 3

Switch On .............................................................................................................. 3

Zero Adjustment ................................................................................................... 3

Current Measurement .......................................................................................... 3

Safety .......................................................................................................................3

Battery Replacement ...............................................................................................3

Frequency Response and Accuracy Curves .............................................................3

Repair ....................................................................................................................... 4

Warnings and Precautions

PLEASE READ SPECIFICATIONS BEFORE OPERATING THE INSTRUMENT

Exceeding the maximum limits of this instrument is DANGEROUS.
Exceeding these limits will expose you to physical injury or even death and will
almost certainly damage your instrument. Even low-level voltages and currents
are capable of causing serious injury or even death.

• Please do not use this or any piece to test equipment without proper

training.

• Individual functions and ranges have different overload limits.

• It is VERY IMPORTANT that you make yourself aware of these overload

limits.

• Check the specifications of these overload limits.

Symbols

Caution! Refer to this manual before using the probe.



Probe is protected by Reinforced or Double Insulation.



Application around and removal from HAZARDOUS



LIVE conductors is permitted.
Conforms to European Union directives.



Introduction

The CT238A current probe has been designed for use with multimeters for
accurate, non-intrusive measurement of both AC, DC and complex waveform
currents.

Using advanced Hall Effect technology the CT238A can accurately measure
currents with a resolution of 1mA from 5mA to 30 Amps over the frequency
range of DC to 20 kHz.

These features make it a powerful tool for use in inverters, switch mode
power supplies, industrial controllers and other applications requiring current
measurement and/or waveform analysis.

1

Specifications

Electrical data

(All accuracies stated at 23°C ± 1°C)
Nominal current In 20 A r.m.s
Measuring range 0 to ±30 A
Overload capacity 500A
Overall DC accuracy ±1% of reading ±2mA
AC accuracy, <1kHz ±1% of reading 2mA
1kHz to 20kHz: ±3% of reading ±2mA
Resolution ±1mA

Typical output noise level 200µV r.m.s.

Gain variation ±0.01% of reading/°C
Output sensitivity 100mV/A
Frequency range DC to 20 kHz
di / dt following 20A/µs
Response time better than 1 µs
Dielectric strength 3.7kV rms 50Hz 1 min
Safety: Meets EN61010-1 Cat III 300V; EN61010-2-032
EMC: Meets EN50081-1, EN50082-1

EMC: This product complies with requirements of

the following European Community Directives: 9/336/EEC (Electromagnetic
Compatibility) and 73/23/EEC (Low Voltage) as amended by 93/68/EEC (CE
Marking).

General data

Operating temperature 0°C to +50°C
Storage temp., battery removed 20°C to +85°C
Environment

- indoor use

- altitude up to 2000m

- maximum relative humidity 80% for temperatures up to 31°C decreasing

linearly to 40% relative humidity at 50°C.

Power supply 9 V Alkaline battery PP3, NEDA 1604 or

Battery life 30 hours typical
Load impedance (minimum) > 10k
Conductor size 19 mm diameter
Jaw opening 20 mm max.
Weight 250 g.
Output cable and connectors 1.5m long terminated with

IEC6F22

 and ≤100pF

4mm safety plugs.

2

Operating Instructions

Refer to Fig. 1.

Switch On

When the probe is switched on the red LED will illuminate. The LED starts
flashing when the battery voltage is too low for normal operation and warns
the user that it requires changing. This procedure is described in Battery
Replacement.

Zero Adjustment

The output zero offset voltage of the probe may change due to thermal shifts
and other environmental conditions. To adjust the output voltage to zero
depress the thumbwheel and rotate. Ensure that the probe is away from the
current carrying conductor when the adjustment is made.

Current Measurement

Switch on the probe using the On - Off switch and check that the LED is lit.
Connect the output lead to a multimeter.
If necessary adjust the probe output voltage to zero as described in section Zero
Adjustment.
Clamp the jaws of the probe round the conductor ensuring a good contact
between the closing faces of the jaws.
Observe and take measurements as required. Positive output indicates that the
current flow is in the direction shown by the arrow on the probe.

True r.m.s. readings may be obtained by using an appropriate true r.m.s.
multimeter.

Safety

This instrument is designed to be safe under the following conditions:
Use of the probe on uninsulated conductors is limited to 300V r.m.s or d.c. and
frequencies below 1kHz.
Safety in its use is the responsibility of the operator who must be a suitably
qualified or authorized person.
Do not use the probe if any part of the probe including the lead and connector(s)
appear to be damaged or if a malfunction of the instrument is suspected.
When using the probe ensure that your fingers are behind the protective barrier
see Fig. 1
Clean the case periodically by wiping it with a damp cloth and detergent. Do not
use abrasive cleaners or solvents. Do not immerse the probe in liquids.

Battery Replacement

Before removing the battery cover, make sure that the probe is remote from any
live electrical circuit.

The red LED will flash when the minimum operating voltage is approached.
Refer to Fig.1 and use the following procedure.

1. Unclamp the probe from the conductor, turn it off using the

switch and disconnect the output leads from external equipment.

2. Loosen the captive screw which secures the battery cover.

3. Lift the cover through 30° and pull it clear of the probe body as shown in

Fig 1. The battery is then accessible.

4. Replace the battery and re-fit the battery cover and fasten the screw.

5. Replacement with other than the specified type of battery will invalidate

the warranty. Fit only Type 9 V PP3, Alkaline (MN 1604).

Frequency Response and Accuracy Curves

Refer to Fig. 2.

 Warning

On - Off

3