Wavetek CT-238 User Manual [en, de, fr]

Operator’s Manual

CT-238

AC/DC Current Probe

• Bedienungsanleitung

• Manuel d’Utilisation

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TM

Accessory

– 1 –

WARRANTY

The CT238 Current Clamp is warranted against any defects of material or
workmanship within a period of one (1) year following the date of purchase of
the multimeter by the original purchaser or original user.
Any multimeter claimed to be defective during the warranty period should be
returned with proof of purchase to an authorized Wavetek Meterman Service
Center or to the local Wavetek Meterman dealer or distributor where your
multimeter was purchased. See maintenance section for details.
Any implied warranties arising out of the sale of a Wavetek Meterman
multimeter, including but not limited to implied warranties of merchantability
and fitness for a particular purpose, are limited in duration to the above stated
one (1) year period. Wavetek Meterman shall not be liable for loss of use of the
multimeter or other incidental or consequential damages, expenses, or
economical loss or for any claim or claims for such damage, expenses or
economical loss.
Some states do not allow limitations on how long implied warranties last or the
exclusion or limitation of incidental or consequential damages, so the above
limitations or exclusions may not apply to you.
This warranty gives you specific legal rights, and you may also have other rights
which vary from state to state.

WARNINGS AND PRECAUTION

PLEASE READ SECTION 2 – SPECIFICATION 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 ot 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.

OPERATING INSTRUCTIONS

CONTENTS

Warranty Statement Page 1
1 INTRODUCTION Page 2
2 SPECIFICATIONS

2.1 Electrical Data Page 3

2.2 General Data Page 3
3 OPERATING INSTRUCTIONS

3.1 Switch On Page 3

3.2 Zero Adjustment Page 3

3.3 Current Measurement Page 3
4 SAFETY Page 4
5 BATTERY REPLACEMENT Page 4
6 FACTORY SERVICE Page 4
7 FREQUENCY RESPONSE

AND ACCURACY CURVES Page 6

International Electrical Symbols

Caution! Refer to this manual before using

the probe.

Probe is protected by Reinforced or Double

Insulation.

– 2 –

1. INTRODUCTION

The CT-238 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 CT-238 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.

2. SPECIFICATION

2.1 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% or 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).

2.2 General data

Operating temperature 0°C to +50°C
Storage temp., battery removed 20°C to +85°C
Power supply 9 V Alkaline battery PP3,
NEDA 1604 or IEC6F22
Battery life 30 hours typical
Load impedance (minimum) > 10kΩ and ≤100pF
Conductor size 19 mm diameter
Jaw opening 20 mm max.
Weight 250 g.
Output cable and connectors 1.5m long terminated with 4mm safety

plugs.

3. OPERATING INSTRUCTIONS

Refer to Fig. 1 (page 3)

3.1 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 Section 5.

3.2 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 whilst the adjustment is made.

3.3 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 3.2
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

– 3 –

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. reading
multimeter.

4. SAFETY

This instrument is designed to be safe under the following conditions:

- indoor use

- altitude up to 2000m

- temperature 0°C to +50°C

- maximum relative humidity 80% for temperatures up to 31°C decreasing
linearly to 40% relative humidity at 50°C.
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 authorised 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.

5. BATTERY REPLACEMENT

SAFETY WARNING: 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.
Unclamp the probe from the conductor, turn it off using the On - Off switch and
disconnect the output leads from external equipment. Loosen the captive screw
which secures the battery cover. Lift the cover through 30°and pull it clear of
the probe body as shown in Fig 1. The battery is then accessible. Replace the
battery and re-fit the battery cover and fasten the screw.Replacement with other
than the specified type of battery will invalidate the warranty. Fit only Type 9 V
PP3, Alkaline (MN 1604 ).

Fig. 1

BATTERY COVER SCREW (CAPTIVE)
SCHRAUBE, BATTERIEFACH
VIS, COMPARTIMENT PILE

JAWS
ZANGE

BATTERY COVER
BATTERIEFACHDECKEL
COUVERCLE, COMP.
PILE

PINCE

ZERO ADJUST
NULLABGLEICH
AJUSTAGE DU
ZERO

LED

ZERO

ADJUST

OFF ON

ON

CT238

AC/DC CURRENT PROBE

OUTPUT: 100mV/A
MAX CURRENT: 20A RMS

PROTECTIVE BARRIER
SCHUTZSPERRE
BOUCLIER DE
PROTECTION

ON/OFF SWITCH
EIN/AUS SCHALTER
BOUTON MARCHE/
ARRET

– 4 –

6. SERVICE INFORMATION

Read the warranty located at the front of this manual before requesting warranty
or non-warranty repairs. For warranty repairs, any multimeter claimed to be
defective can be returned to any Wavetek Meterman authorized distributor or to
a Wavetek Meterman Service Center for an over-the-counter exchange for the
same or like product. Non-warranty repairs should be sent to a Wavetek
Meterman Service Center. Please call Wavetek Meterman or enquire at your
point of purchase for the nearest location and current repair rates. All
multimeters returned for warranty or non-warranty repair or for calibration
should be accompanied by the following information or items: company name,
customer’s name, address, telephone number, proof of purchase (warranty
repairs), a brief description of the problem or the service requested, and the
appropriate service charge (for non-warranty repairs). Please include the test
leads with the meter. Service charges should be remitted in the form of a check,
a money order, credit card with expiration date, or a purchase order made
payable to Wavetek Meterman or to the specific service center. For minimum
turn-around time on out-of-warranty repairs please phone in advance for
service charge rates. The clamp should be shipped with transportation charges
prepaid to one of the following addresses or to a service center:

in U.S.A. in Canada in Europe
Wavetek Meterman Wavetek Meterman Wavetek Meterman
1420 75th Street SW 400 Britannia Rd. E.Unit #1 52 Hurricane Way
Everett, WA 98203 Mississauga, ON L4Z 1X9 Norwich, NR6 6JB, U.K.
Tel: [phone] Tel: [phone] Tel: int + 44-1603-404824
Fax: [phone] Fax: [phone] Fax: int + 44-1603­482409

The instrument will be returned with the transportation charges paid by Wavetek
Meterman.

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Frequency in Hz; Frequenz in Hz; Fréquence en Hz

Frequency Response CT-238

Frequenzgang CT-238

Réponse de Fréquence CT-238

20000

-2,00

-1,50

-1,00

-0,50

0,00

0,50

1,00

1,50

2,00

% Error Of Reading; % Ablesefehler; %

Erreur de Lecture

510152025

30

A

Typical Accuracy; CT-238

Typische Genauigkeit, CT-238

Précision Typique, CT-238

50mA

-3

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-1

0

1

10 1000 100000

Gain in dB; Verstärkung in dB; Gain en dB

20000

Frequency In Hz; Frequenz in Hz; Fréquence en Hz

Frequency Response CT-238

Frequenzgang CT-238

Réponse de Fréquence CT-238

Fig. 2

Gain in dB • Verstärkung in dB • Gain en dB

% Error of reading • % Ablesefehler • Erreur de Lecture

Frequency in Hz • Frequenz in Hz • Fréquence en Hz

Frequency in Hz • Frequenz in Hz • Fréquence en Hz

Phase shift in degrees • Phasenverschiebung in Grad

• Déphasage en degrés

– 5 –

.7 Frequency Response

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TM