Hioki 3273 Instruction Manual

INSTRUCTION MANUAL

3273

CLAMP ON PROBE

Contents

Introduction i
Inspection
Safety Notes
Note on Use

i
i

iv

Chapter 1 Overview

1.1 Product Overview 1

1.2 Features

1.3 Names of Parts

1.4 Parts of the Sensor

Chapter 2 Specifications 5

2.1 Product Specifications 5

2.2 Standards Applying

Chapter 3 Measurement Procedure 9

3.1 Notes on Use 9

3.2 Preparations for Measurement

3.3 Demagnetizing and Zero Adjustment

3.4 Measurement Procedure

13
14
16

1

1
2
3

7

____________________________________________________

Introduction

Thank you for purchasing the HIOKI "3273 CLAMP
ON PROBE". To obtain maximum performance
from the device, please read this manual first, and
keep it handy for future reference.

Inspection

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
Soft case 1

Safety Notes

WARNING

This device is designed to comply with IEC
61010-1 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.

i

___________________________________________

Introduction

ii

____________________________________________________

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 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.

The following symbols in this manual indicate the
relative importance of cautions and warnings.

Indicates that incorrect operation

DANGER

presents an extreme hazard that could
result in serious injury or death to the
user.

Indicates that incorrect operation

WARNING

presents a significant hazard that could
result in serious injury or death to the
user.

Indicates that incorrect operation

CAUTION

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 Notes

____________________________________________________

iii

Overvoltage Categories (CAT)

This device conforms to the safety requirements for CAT I
measurement instruments.
To ensure safe operation of measurement instruments, IEC
60664 establishes safety standards for various electrical
environments, categorized as CAT I to CAT IV, and called
overvoltage categories. These are defined as follows.
CAT I : Secondary electrical circuits connected to an AC

electrical outlet through a transformer or similar
instrument.

CAT II : Primary electrical circuits in equipment

connected to an AC electrical outlet by a power
cord (portable tools, household appliances, etc.)

CAT III : Primary electrical circuits of heavy equipment

(fixed installations) connected directly to the
distribution panel, and feeders from the
distribution panel to outlets.

CAT IV : The circuit from the service drop to the service

entrance, and to the power meter and primary
overcurrent protection instrument (distribution

panel).
Higher-numbered categories correspond to electrical
environments with greater momentary energy, so a
measurement instrument designed for CAT III
environments can endure greater momentary energy than
one designed for CAT II. Using a measurement instrument
in an environment designated with a higher-numbered
category than that for which the instrument is rated could
result in a severe accident, and must be carefully avoided.

___________________________________________

Safety Notes

iv

____________________________________________________

Note on Use

Follow these precautions to ensure safe operation
and to obtain the full benefits of the various
functions.

DANGER

To avoid short circuits and potentially life­threatening hazards, follow these precautions.

Never attach the 3273 to a circuit that operates
at more than 300V, or over bare conductors.
While the core section is open, and when
conductors being measured carry in excess of
the safe voltage level (SELV-E) and not more
than 300 V, make sure that conductors to be
measured are insulated with material
conforming to (1) Overvoltage Category I,(2)
Basic Insulation Requirements for Working
Voltages of 300 V, and (3) Pollution Degree 2.
For safeties sake, never use this sensor on
bare conductors. The core and shield case are
not insulated.
Be careful to avoid damaging the insulation
surface while taking measurements.

___________________________________________

Note on Use

____________________________________________________

DANGER

This device is made for use with the 3272
POWER SUPPLY. It is possible to use a power
supply other than the 3272, provided that the
connector and pin assignments match, and that
voltage and other electrical specifications are
satisfied. In the interest of safety, make sure
that the power supply has a protective earthing
with double-insulation construction.
Make sure that the waveform measuring
equipment connected to this device's output
terminal (BNC) is equipped with a protective
earthing with double-insulation construction.
To avoid electric shock, do not touch the
portion beyond the barrier during use.
If the waveform measuring instrument being
connected to the output terminal (BNC) on this
device is equipped with any other measurement
terminals, take the following precautions to
ensure that the other instrument does not form
a bridge between the probe and any hazardous
live of a part.

1. Isolate the terminal to which the probe is
connected from other terminals on the
measuring instrument using basic insulation
conforming to the overvoltage category,
working voltage, and pollution degree
requirements of the circuit being tested.

v

___________________________________________

Note on Use

vi

____________________________________________________

DANGER

2. If basic insulation requirements cannot be
met between the terminal to which this device
is connected and other terminals of the
measuring instrument, make sure that the
voltage input to the measurement terminal
does not exceed the safe voltage level (SELV­E).

3. Read and observe all warnings and
precautions relating to electrical safety for the
measuring instrument being connected to the
probe.

Refer to the following standards regarding the
meanings of underlined terms.

IEC61010-1
IEC61010-2-031
IEC61010-2-032

___________________________________________

Note on Use

____________________________________________________

DANGER

vii

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
When using a measurement instrument that
does not p rovide 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 3272 or this device
from the ground terminal, which could cause an
electrical accident or damage.

___________________________________________

Note on Use

viii

____________________________________________________

WARNING

Do not allow the device to get wet, and do not
take measurements with wet hands. This may
cause an electric shock.

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 or
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.

___________________________________________

Note on Use

____________________________________________________

CAUTION

ix

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.
Measurements are degraded by dirt on the mating
surfaces of the sensor head, so keep the surfaces
clean by gently wiping with a soft cloth.
To avoid damaging the sensor cable and power
supply cable, do not bend or pull the cables.
When the power is on, keep the core section of the
sensor 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.

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.

___________________________________________

Note on Use

x

____________________________________________________

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 damage is suspected, contact your dealer or
Hioki representative.
When sending the device for repair, pack
carefully to prevent damage in transit. Include
cushioning material so the 3273 cannot move
within the package. Be sure to include details of
the problem. Hioki cannot be responsible for
damage that occurs during shipment.

___________________________________________

Note on Use

____________________________________________________

Chapter 1

Overview

1.1 Product Overview

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.

1.2 Features

Highly accurate current detection
Easy current measurement

Broadband frequency characteristics DC to 50
MHz
Compact and permits measurement of low current
levels
Easy protect function at excessive input
Unique HIOKI development of thin film Hall
effect element

1

_______________________________________________

Chapter 1 Overview

2

____________________________________________________

1.3 Names of Parts

External view

Current direction
indication

2

8

1

"UNLOCK" indication

Sensor cable

5

Sensor Terminator

3

Power supply
cable

6

7

4

_______________________________________________

Chapter 1 Overview

____________________________________________________

1.4 Parts of the Sensor

1. Opening lever
Operating lever for opening the sensor head. Always
use this lever to open the sensor head.

2. 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.

3. 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 one second.
During demagnetizing, a demagnetizing waveform is
output.

4. 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.

5. Coarse adjustment trimmer
Use this only when adjustment is not possible within
the range of the zero adjustment dial. Use a
nonconductive screwdriver (e.g., ceramic driver) for
adjustment.

3

_______________________________________________

Chapter 1 Overview

4

____________________________________________________

6. Output connector
The current waveform of the measured conductor is
output at a constant rate (0.1 V/A).
Connect to the BNC input connector of the waveform
measuring instrument.

NOTE

7. Power plug

8. Barrier

The output of this device is terminated internally.
Use a high-impedance input to the measuring
instrument. With an input impedance of 50Ω,
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.

Connect this to the 3272 POWER SUPPLY
receptacle to supply power to the sensor terminator.

This structure reduces the likelihood of touching the
conductor while testing, and indicates the limit of
safe physical contact. Avoid touching the clamp in
front of the barrier when clamping or measuring.

_______________________________________________

Chapter 1 Overview

____________________________________________________

Chapter 2

Specifications

2.1 Product Specifications

Guaranteed at 23
power has been on for 30 minutes.

Frequency
range

Rise time

Maximum
continuous input
range

Maximum peak
current value

Output voltage
rate

Amplitude
accuracy

Noise

Input impedance

Temperature
coefficient for
sensitivity

DC to 50 MHz (-3 dB) (Characteristics
shown in Fig. 1)

7nsorless

15 A
Derating according to frequency shown
in Fig. 2

Non-continuous 30 A peak; at pulse
width

0.1 V/A

0.5% rdg. 1mV
(DC, and 45 to 66 Hz, input within
continuous maximum input range)

Equivalent to 2.5 mA rms or less (for 20
MHz band measuring instrument)

(Characteristics shown in Fig.3)

2% or less (within a range of 0 to 40
, within a range of 32 to 104 )

(73

±5

10µs, 50 A peak

±9

) after the

5

_______________________________________________

Chapter 2 Specifications

6

____________________________________________________

Maximum rated
power

Rated supply
voltage

Operating
temperature and
humidity range

Storage
temperature and
humidity range

Location for use

Period of
guaranteed
accuracy

Effect of
external
magnetic fields

Maximum rated
voltage to earth

Diameter of
measurable
conductors

Cable lengths

External
dimensions

3VA

12 V 1V

0to40 (32 to 104 ), 80 %RH or
less (no condensation)

10 to 50 (14 to 122 ), 80 %RH or

-

less (no condensation)

Indoor, altitude up to 2000 m (6562 feet)

1 year (Opening/Closing up to 10,000
times)

Equivalent to a maximum of 20 mA (in
a 60 Hz,400 A/m AC current magnetic
field)

300 V, CAT I (insulated conductor)

5mmdia.

0.2" dia.

Sensor cable Approx. 1.5 m (59.0")
Power supply cable Approx. 1 m (39.4")

Sensor

Approx. 175Wx18Hx40Dmm
Approx. 6.89"Wx0.71"Hx1.58"D

Terminator

Approx. 27Hx55Wx18D mm
Approx. 1.06"Wx2.17"Hx0.71"D

_______________________________________________

Chapter 2 Specifications

____________________________________________________

Mass

Accessories

Approx. 230 g
Approx. 8.1 oz.

Instruction manual, soft case

2.2 Standards Applying

7

Safety

EMC

]
V

1
=
B
d
0

[
e

d
u

t

i

l
p

m
A

EN61010-2-032:1995
Overvoltage category I (anticipated
transient overvoltage 1500 V),
Pollution Degree 2

EN61326:1997+A1:1998+A2:2001

Frequency [Hz]

Figure1 Frequencycharacteristics

_______________________________________________

Chapter 2 Specifications

8

____________________________________________________

]
A

[
t
n
e

r

r
u
c
t
u
p
n

i
m

u
m

i
x
a

M

Frequency [Hz]

Figure2 Derating according to frequency

]

Ω

[
e

c
n
a
d
e
p

m

i
t
u
p
n

I

Figure3 Input impedance (Characteristics)

Frequency [Hz]

_______________________________________________

Chapter 2 Specifications

____________________________________________________

Chapter 3

Measurement

Procedure

3.1 Notes on Use

DANGER

To avoid short circuits and potentially life­threatening hazards, follow these precautions.

Never attach the 3273 to a circuit that operates
at more than 300V, or over bare conductors.
While the core section is open, and when
conductors being measured carry in excess of
the safe voltage level (SELV-E) and not more
than 300 V, make sure that conductors to be
measured are insulated with material
conforming to (1) Overvoltage Category I,(2)
Basic Insulation Requirements for Working
Voltages of 300 V, and (3) Pollution Degree 2.
For safeties sake, never use this sensor on
bare conductors. The core and shield case are
not insulated.
Be careful to avoid damaging the insulation
surface while taking measurements.

9

_______________________________________________

3 Measurement Procedure

Chapter

10

____________________________________________________

DANGER

This device is made for use with the 3272
POWER SUPPLY. It is possible to use a power
supply other than the 3272, provided that the
connector and pin assignments match, and that
voltage and other electrical specifications are
satisfied. In the interest of safety, make sure
that the power supply has a protective earthing
with double-insulation construction.
Make sure that the waveform measuring
equipment connected to this device's output
terminal (BNC) is equipped with a protective
earthing with double-insulation construction.
To avoid electric shock, do not touch the
portion beyond the barrier during use.
If the waveform measuring instrument being
connected to the output terminal (BNC) on this
device is equipped with any other measurement
terminals, take the following precautions to
ensure that the other instrument does not form
a bridge between the probe and any hazardous
live of a part.

1. Isolate the terminal to which the probe is
connected from other terminals on the
measuring instrument using basic insulation
conforming to the overvoltage category,
working voltage, and pollution degree
requirements of the circuit being tested.

_______________________________________________

Chapter 3 Measurement Procedure

____________________________________________________

DANGER

11

2. If basic insulation requirements cannot be
met between the terminal to which this device
is connected and other terminals of the
measuring instrument, make sure that the
voltage input to the measurement terminal
does not exceed the safe voltage level (SELV­E).

3. Read and observe all warnings and
precautions relating to electrical safety for the
measuring instrument being connected to the
probe.

Refer to the following standards regarding the
meanings of underlined terms.

IEC61010-1
IEC61010-2-031
IEC61010-2-032

_______________________________________________

Chapter 3 Measurement Procedure

12

____________________________________________________

DANGER

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
When using a measurement instrument that
does not p rovide 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 3272 or this device
from the ground terminal, which could cause an
electrical accident or damage.

_______________________________________________

Chapter 3 Measurement Procedure

____________________________________________________

13

3.2 Preparations for Measurement

(1) Have the 3272 POWER SUPPLY, and oscilloscope

or recorder for waveform measurement ready.

CAUTION

Before turning on the power, make sure that the
voltage of the power supply being used matches the
supply voltage indicated on the rear panel of the

3272.

(2) Turn the power switch off and connect the power

cord.

(3) Connect the power plug of the 3273 to the power

receptacle of the 3272.

(4) Turn the 3272 power switch on, and check that the

front panel power indicator lights.

_______________________________________________

Chapter 3 Measurement Procedure

14

____________________________________________________

3.3 Demagnetizing and Zero Adjustment

NOTE

The output of this device is terminated internally.
Use a high-impedance input to the measuring
instrument. With an input impedance of 50Ω,
accurate measurement is not possible.

(1) With the waveform measurement instrument input at

ground, adjust the trace to the zero position.

(2) Set the input coupling of the waveform measurement

instrument to DC.

(3) Connect the output connector of the 3273 to the

input connector of the waveform measurement
instrument. Turn the collar until it clicks, and check
that it is locked securely.

_______________________________________________

Chapter 3 Measurement Procedure

____________________________________________________

g

CAUTION

15

When disconnecting the output connector, be sure
to release the lock, then pull the connector.
Forcibly pulling the connector without releasing the
lock, or pulling on the cable will result in damage to
the terminator.
If using BNC-banana plug adapters or similar to
connect to input terminals other than BNC
connectors, make sure the polarity is correct.
Do not demagnetize while the 3273 is clamping a
conductor to be measured. Demagnetizing causes
current to flow into the conductor, which may
damage parts in the circuit to be measured.

Demagnetizin

Conductor

Check that the conductor being measured is not
clamped when supplying power to the 3273 for the
same reason. Demagnetized waveforms are
generated when supplying electric power.

(4) Without clamping the conductor to be measured,

press the opening lever until the "UNLOCK"
indication disappears, and check that the sensor
head is properly closed.

(5) Press the demagnetizing switch (DEMAG) on the

terminator.

(6) Turn the zero adjustment dial on the terminator, to

adjust the trace to the zero position.

_______________________________________________

Chapter 3 Measurement Procedure

16

____________________________________________________

(7) If zero adjustment is not possible in step 6, turn the

coarse adjustment trimmer to bring the trace within
the range of adjustment by the zero adjustment dial.

3.4 Measurement Procedure

(1) Check that the system is safe, and that the

preparations described in the preceding section have
been carried out.

(2) Pull the sensor opening lever, so that the sensor

head opens.

Opening lever

(3) Align the sensor so that the current direction

indication corresponds to the direction of current
flow through the conductor to be measured, and
clamp so that the conductor is in the center of the
sensor aperture.

(4) Press the opening lever on the sensor head until the

"UNLOCK" indication disappears, and check that
the opening lever is firmly locked and the sensor
head securely closed.

_______________________________________________

Chapter 3 Measurement Procedure

____________________________________________________

17

(5) It is now possible to monitor the current
waveform. The output rate of the 3273 is 0.1 V/A.
The current sensitivity can be derived from the
voltage sensitivity of the waveform measurement
instrument. For example, if the voltage sensitivity is
10 mV/division, the current sensitivity is 100
mA/division.

･ When using the 3273, note that two clamp-on

NOTE

probes may not be used simultaneously with the
3272 POWER SUPPLY, depending on the current
to be measured.

･ The current consumption of clamp-on probes

depends on the current to be measured. Confirm
that the total current consumption of the clamp-on
probes does not exceed the rated output current of
the 3272. See Figure 1.

600

500

400

300

200

current consumption (mA)

100

0

0 1020304050

AC(f=50Hz)
DC

Fig.1

Current consumption* vs. current to be measured(typical)

*The sum total of a positive and negative current consumption

_______________________________________________

Chapter 3 Measurement Procedure

18

____________________________________________________

WARNING

The maximu m continuous input range is based
on heat that is internally generated during
measurement. Never input current in excess of
this level. Exceeding the rated level may result
in damage to the probe.
The maximum continuous input range varies
according to the frequency of the current being
measured. See the figures in 2.1, "Product
Specifications"
If excess current is input, generated heat
activates a built-in safety function that blocks
normal output. If this happens, remove the
input immediately (remove the sensor from the
conductor being measured, or reduce the input
current to zero). Wait until the sensor has had
sufficient time to cool before resuming
operation.
Even if the input current does not exceed the
rated continuous maximum, continuous input
for an extended period of time may result in
activation of the safety circuit to prevent
damage resulting from heating of the sensor.
At high ambient temperatures, the built-in safety
circuit may activate at current input levels
below the rated continuous maximum.
Continuous input of current exceeding the rated
maximum or repeated safety circuit activation
will degrade performance of the safety circuit,
possibly resulting in damage to the device.

_______________________________________________

Chapter 3 Measurement Procedure

____________________________________________________

WARNING

19

The probe is rated for maximum input under
two conditions in addition to the input
maximums shown in the "Product
Specifications." These are (1) 30 Apeak, for
non-continuous input, and (2) 50 Apeak for
pulse widths 10µs. (1) indicates an upper
waveform response limit of 30 Apeak. Use the
sensor at RMS current input levels that are
within the rated continuous maximums. (2)
indicates the upper response limit for a single
input pulse.
When opening the sensor head of the probe, be
sure to operate with the opening lever. If an
upper core is forced to open, when the sensor
head is locked, the open-close mechanism can

Do not press

NOTE

Upper core

The output of this device is terminated internally.
Use a waveform measurement instrument with an

Lock state

input impedance of at least 1 MΩ.
Immediately after powering on, this device may be
subject to an appreciable offset drift due to the
effect of self-heating. To counteract this, allow the
device to warm up for about 30 minutes before
carrying out measurement.

_______________________________________________

Chapter 3 Measurement Procedure

20

____________________________________________________

NOTE

When performing continuous measurements, it is
necessary to be aware that the offset voltage drifts,
depending on factors such as the ambient
temperature.
Under certain circumstances, oscillation may occur
if the probe is connected to the 3272 POWER
SUPPLY while the power supply is on. This does
not indicate a malfunction. Oscillation can be
stopped and operation restored to normal by
opening and closing the sensor head.
Depending on the measured current frequency,
however some sound may be produced by
resonance, it has no effect on measurements.
The reading may be affected by the position within
the clamp aperture of the conductor being
measured. The conductor should be in the center of
the clamp aperture.
When carrying out measurement, press the opening
lever until the "UNLOCK" indication disappears,
and check that the sensor head is properly closed. If
the sensor head is not properly closed, accurate
measurement will not be possible.
At high frequencies, common mode noise may
affect measurements taken on the high voltage side
of circuits. If this occurs, reduce the frequency
range of the waveform measuring instrument, or
clamp onto the low-voltage side of the circuit, as
appropriate.

_______________________________________________

Chapter 3 Measurement Procedure

____________________________________________________

21

H

NOTE

Power
source

Load

L

Accurate measurement may be impossible in
locations subject to strong external magnetic
fields, such as transformers and high-current
conductors, or in locations subject to strong
external electric fields, such as radio transmission
equipment.

_______________________________________________

Chapter 3 Measurement Procedure

22

____________________________________________________

_______________________________________________

Chapter 3 Measurement Procedure