Hioki 3274 User manual

EN
3275
CLAMP ON PROBE
3274
Instruction Manual
May 2015 Revised edition 5
3275A981-05 15-05H
99 Washington Street
Melrose, MA 02176
Phone [phone]
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com

Contents
Introduction 1
Inspection 1
Notes on Safety 1
Notes on Use 4
Chapter 1 Overview 9
1.1 Product Overview 9
1.2 Features 9
1.3 Names of Parts 10
1.4 Parts of the Sensor 11
Chapter 2 Specifications 13
2.1 Product Specifications 13
2.2 Standards Applying 15
Chapter 3 Measurement Procedure 19
3.1 Notes on Use 19
3.2 Preparations for Measurement 20
3.3 Demagnetizing and Zero Adjustment 21
3.4 Measurement Procedure 22
3275A981-05

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WARNING This device is designed to comply with IEC 61010
Safety Standards, and has been thoroughly tested for
safety prior to shipment. However, mishandling
during use could result in injury or death, as well as
damage to the device. Be certain that you understand
the instructions and precautions in the manual before
use. We disclaim any responsibility for accidents or
injuries not resulting directly from device defects.
Introduction
Inspection
Notes on Safety
Thank you for purchasing this HIOKI 3274, 3275 CLAMP ON
PROBE.
To obtain maximum performance from the device, please read this
manual first, and keep it handy for future reference.
When you receive the device, inspect it carefully to ensure that no
damage occurred during shipping. If damage is evident, or if it
fails to operate according to the specifications, contact your dealer
or Hioki representative.
Supplied accessories
Instruction manual 1
Carrying case 1

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The symbol printed on the device indicates that the user
should refer to a corresponding topic in the manual
(marked with the symbol) before using the relevant
function.
In the manual, the symbol indicates particularly
important information that the user should read before
using the device.
Indicates that only insulated conductors suited to the
voltage of the circuit under test can be measured.
DANGER
Indicates that incorrect operation presents an extreme
hazard that could result in serious injury or death to the
user.
WARNING
Indicates that incorrect operation presents a significant
hazard that could result in serious injury or death to the
user.
CAUTION Indicates that incorrect operation presents a possibility of
injury to the user or damage to the device.
NOTE Indicates advisory items related to performance or correct
operation of the device.
Safety Symbols
This manual contains information and warnings essential for safe
operation of the device and for maintaining it in safe operating
condition. Before using the device, be sure to carefully read the
following safety notes.
The following symbols in this manual indicate the relative
importance of cautions and warnings.

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DANGER Do not measure around a bare conductor. Doing so
may result in short-circuit or electric shock. Take
measurements at a location on an insulated wire
where there is sufficient insulation for the circuit
voltage.
Refer to the derating characteristics when
measuring current that includes a highfrequency
component and never measure any current that
exceeds the rated current.
Use with high frequencies or strong magnetic fields
may cause the device to become abnormally hot,
resulting in fire, equipment damage, or burns. (See
〝2 Specifications〟(p. 12).)
Observe the following to avoid electric shock and
short circuits.
Connect the device to the 3269 or the 3272 Power
Supply and waveform measurement
instrument (oscilloscope or recorder) first,and then
to the active lines to be measured.
When the sensor is opened, do not shortcircuit the
conductor being measured or other two wires with
the metal part of the tip.
Be careful to avoid damaging the insulation surface
while taking measurements.
Notes on Use
Follow these precautions to ensure safe operation and to obtain
the full benefits of the various functions.

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DANGER Before clamping the conductor being measured,
make sure that the insulation on the conductor is
undamaged. Also, take care not to damage the
insulation when clamping the conductor. Any damage
to the insulation could cause an electric shock.
This instrument is made for use with the 3269 or
3272 POWER SUPPLY.
To prevent fire or damage of the measurement
target and device as well as burns, exercise
caution concerning the following when measuring
high-frequency currents or currents that contain
high-frequency components:
Eddy current loss may cause heating of the
sensor head.
Dielectric heating may cause heating of cord
insulation and other materials.
This device should only be connected to the
secondary side of a breaker, so the breaker can
prevent an accident if a short circuit occurs.
Connections should never be made to the primary
side of a breaker, because unrestricted current flow
could cause a serious accident if a short circuit
occurs.
Be sure to observe all operating precautions for the
waveform monitoring instrument (oscilloscope or
recorder) and other measurement instruments to
which this device is connected.

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DANGER When using a measurement instrument that does
not provide isolation between its input terminals
and chassis or other input terminals, please pay
attention to the following points.
If a signal is applied to an input terminal other than
that to which this device is connected, do not
connect the ground-side terminal to any non-
ground potential. Otherwise, short-circuit current
will flow through the 3269 or 3272, or this device
from the ground terminal, which could cause an
electrical accident or damage.
Power Source
Load Load

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WARNING Do not allow the device to get wet, and do not take
measurements with wet hands. This may cause an
electric shock.
Do not press the demagnetizing switch (DEMAG) to
perform demagnetization while the conductor being
measured is clamped. Doing so could damage the
circuitry or cause an accident that might result in
injury or death.
Ensure that the input does not exceed the
maximum rated current to avoid device damage,
shortcircuiting and electric shock resulting from
heat building.
CAUTION To avoid damage to the device, protect it from vibration
or shock during transport and handling, and be
especially careful to avoid dropping.
Do not store or use the device where it could be
exposed to direct sunlight, high temperature, humidity,
or condensation. Under such conditions, the device
may be damaged and insulation may deteriorate so
that it no longer meets specifications.
Before using the device the first time, verify that it
operates normally to ensure that the no damage
occurred during storage or shipping. If you find any
damage, contact your dealer or Hioki representative.
This device is not designed to be entirely water- or
dust- proof. To avoid damage, do not use it in a wet or
dusty environment.
The sensor head is a precision assembly including a
molded component, a ferrite core, and a Hall effect
element. It may be damaged if subjected to sudden
changes in ambient temperature, or mechanical strain
or shock, and therefore great care should be exercised
in handling it.

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CAUTION The matching surfaces of the sensor head are
precision ground, and should be treated with care. If
these surfaces are scratched, performance may be
impaired.
Do not apply a static electricity or other source of high
voltage to the sensor. Doing so may damage its
internal Hall elements and circuitry.
Foreign substances such as dust on the contact
surfaces of the sensor head can cause acoustic
resonance and degrade measurement, so it should be
cleaned by gently wiping with a soft cloth.
Refer to NOTE (p26) for resonance sound.
To avoid damaging the sensor cable and power supply
cable, do not bend or pull the cables.
When the power is on, keep closed, except when
clamping them onto the conductor to be measured.
The facing surface of the core section can be scratched
while it is open.
Do not short-circuit the output terminal and do not input
voltage to the output terminal. The device may be
damaged.
Note that the device may be damaged if the applied
current exceeds the measurement range.
When the 3269, 3272 Power Supply or waveform
measurement instrumentʼs power is turned off, do not
apply current to the device. Doing so may damage the
device, the 3269, 3272 Power Supply and/or waveform
measurement instrument.
NOTE Correct measurement may be impossible in the presence of strong
magnetic fields, such as near transformers and high-current
conductors, or in the presence of strong electromagnetic fields
such as near radio transmitters.

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Service / Maintenance
To clean the device, wipe it gently with a soft cloth moistened
with water or mild detergent. Never use solvents such as
benzene, alcohol, acetone, ether, ketones, thinners or gasoline, as
they can deform and discolor the case.
If the device seems to be malfunctioning, contact your dealer or
Hioki representative.
When sending the device for repair, pack carefully to prevent
damage in transit. Include cushioning material so the device
cannot move within the package. Be sure to include details of
the problem.
Hioki cannot be responsible for damage that occurs during
shipment.
Use the original packing materials when transporting the device,
if possible.
Transport the device in its carrying case.

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Chapter 1 Overview
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Chapter 1
Overview
1.1 Product Overview
1.2 Features
This device can be directly connected to a BNC input connector
of a waveform measuring instrument such as an oscilloscope or
recorder, and by clamping on a conductor to be measured, allows
the current waveform to be easily captured.
Highly accurate current detection.
Easy current measurement.
Broadband frequency characteristics.
Model 3274 : DC to 10 MHz
Model 3275 : DC to 2 MHz
Large diameter allows high-current measurements.
Easy protection function to avoid self-heating during excessive
input.
Unique HIOKI development of thin film Hall effect element

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Chapter 1 Overview
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Current direction indication "LOCK" indication Terminato
r
Sensor cable
Power supply cable
"UNLOCK" indication
(inside)
Sensor
7
8
1
4
3
2
5
6
2
1.3 Names of Parts
External view

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Chapter 1 Overview
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1.4 Parts of the Sensor
1. Clamp
This clamps around the conductor to be measured.
2. Slider
This slider opens the clamp. Always use it to open and close the
clamp.
3. Lever
This lock mechanism keeps the clamp closed.
4. Sensor head
This clamps the conductor being measured, and carries out the
actual current measurement. It is a precision assembly including a
molded component, a ferrite core, and a Hall effect element. It
may be damaged if subjected to sudden changes in ambient
temperature, or mechanical strain or shock, and therefore great
care should be exercised in handling it.
5. Demagnetizing switch (DEMAG)
This demagnetizes the core if it has been magnetized by switching
the power on and off, or by an excessive input. Always carry out
demagnetizing before measurement.
The demagnetizing process takes about 3 second. During
demagnetizing, a demagnetizing waveform is output.
6. Zero adjustment dial (ZERO ADJ)
Use the zero adjustment dial to correct for the effect of a voltage
offset or temperature drift on the device.
When beginning measurement, after demagnetizing always carry
out zero adjustment.

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Chapter 1 Overview
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NOTE
7. Output connector
The current waveform of the measured conductor is output at a
constant rate (0.01 V/A).
Connect to the BNC input connector of the waveform measuring
instrument.
The output of this device is terminated internally.
Since the output resistance is approx. 7 Ω(model 3274) and
approx. 40 Ω(model 3275), the device must be used with a
high-impedance input to the measuring instrument. With an input
impedance of 50 Ω, accurate measurement is not possible.
If using BNC-banana plug adapters or similar to connect to input
terminals other than BNC connectors, make sure the polarity is
correct.
Turn the collar until it clicks, and check that it is locked
securely.
8. Power plug
Connect this to the 3269 or 3272 POWER SUPPLY receptacle to
supply power to the sensor terminator.

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Chapter 2 Specifications
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Bandwidth Model 3274 : DC to 10 MHz (-3 dB)
(Typical characteristics shown in Fig.1)
Model 3275 : DC to 2 MHz (-3 dB)
(Typical characteristics shown in Fig.2)
Rise time Model 3274 : 35 ns or less
Model 3275 : 175 ns or less
Maximum
continuous input
range
Model 3274 : 150 A
(Derating according to frequency shown in Fig.3)
Model 3275 : 500 A
(Derating according to frequency shown in Fig.4)
Maximum peak
current value
Model 3274 : Non-continuous 300 A peak
500 A peak at pulse width ≦30μs
Model 3275 : Non-continuous 700 A peak
Output voltage rate 0.01 V/A
Amplitude
accuracy
Model 3274 : To 150 A: 1.0% rdg. 1mV
150 A to 300 Apeak: 2.0% rdg.
(DC, and 45 to 66 Hz)
Model 3275 : To 500 A: 1.0% rdg. 5mV
To 700 Apeak: 2.0% rdg.
(DC, and 45 to 66 Hz)
Noise Equivalent to 25 mA rms or less (for 20 MHz band
measuring instrument)
Input impedance Model 3274 (Typical characteristics shown in Fig.5)
Model 3275 (Typical characteristics shown in Fig.6)
Chapter 2
Specifications
2.1 Product Specifications
Guaranteed at 23 ±3(73 ±5.4 ) after the power has
been on for 30 minutes.

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Chapter 2 Specifications
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Temperature
coefficient for
sensitivity
2% or less
Model 3274 (Input: 55 Hz 150 A, within a range of 0
to 40 , within a range of 32 to 104 )
Model 3275 (Input: 50 Hz 500 A, within a range of 0
to 40 , within a range of 32 to 104 )
Maximum rated
power
Model 3274 : 5.5 VA
Model 3275 : 7.2 VA
(within maximum continuous input range)
Rated supply
voltage
Model 3274 : 12 V 1V
Model 3275 : 12 V 0.5 V
Operating
temperature and
humidity range
0to40 (32 to 104 ), 80 % RH or less (no
condensation)
Storage
temperature and
humidity range
-10 to 50 (14 to 122 ), 80 % RH or less (no
condensation)
Location for use Indoor, altitude up to 2000 m (6562 feet), Pollution
Degree 2
Period of
guaranteed
accuracy
1 year (Opening/Closing up to 10,000 times)
Effect of external
magnetic fields
Model 3274 : Equivalent to a maximum of 150 mA
Model 3275 : Equivalent to a maximum of 800 mA
(in a DC or 60 Hz, 400 A/m magnetic field)
Diameter of
measurable
conductors
20 mm dia.
0.79"dia.
Measurable
conductors
Insulated conductor
Cable lengths Sensor cable Approx. 2 m (78.7")
Power supply cable Approx. 1 m (39.4")
External
dimensions
Sensor Approx. 176W X69H X27D mm
Approx. 6.93"WX2.72"HX1.06"D
Terminator Approx. 27H X55W X18D mm
Approx.1.06"WX2.17"HX0.71"D
Mass Model 3274 : Approx. 500 g (Approx. 17.6 oz.)
Model 3275 : Approx. 520 g (Approx. 18.3 oz.)
Accessories Instruction manual, Carrying case

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Chapter 2 Specifications
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Safety EN61010
EMC EN61326
2.2 Standards Applying

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Chapter 2 Specifications
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Fig.1 Frequency characteristics (Typical) (3274)
Fig.2 Frequency characteristics (Typical) (3275)
Fig.3 Derating according to frequency(3274)

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Chapter 2 Specifications
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Fig.6 Input impedance (Typical) (3275)
Fig.4 Derating according to frequency(3275)
Fig.5 Input impedance (Typical) (3274)

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Chapter 2 Specifications
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