Hioki 3270 Instruction Manual

INSTRUCTION MANUAL

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3270

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CURRENT MONITOR

Contents

Introduction 1
Notes on Safety 1
Inspection 3
Precautions 3

Chapter 1 3270 Current Monitor 5

1.1 Product Overview 5

1.2 Identification of Indicators 6

1.3 Product Specifications 6

1.4 Measurement Procedure 9

1.4.1 Preparation 9

1.4.2 Measurement 10

1.4.2.1 When Using the 9273 11

1.4.2.2 When Using the 9274 13

1.4.2.3 When Using the 9275 16

1.4.2.4 When Using the 9276 18

1.4.3 Explanation of Each Function 20

1.4.3.1 Connector 20

1.4.3.2 Output Terminals 20

1.4.3.3 Measurement ranges 21

1.4.3.4 Demagnetizing (DEMAG) 23

1.4.3.5 Zero adjustment (ZERO ADJ.) 23

1.4.3.6 Coupling (COUPLING) 24

1.4.3.7 Filter (FILTER) 24

1.4.3.8 Overload indicator (OVERLOAD) 25

1.5 Fuse Replacement 25

Chapter 2 9273 Clamp-On AC Sensor 27

2.1 Product Specifications 27

Chapter 3 9274 Clamp-On AC/DC Sensor 31

3.1 Product Specifications 31

Chapter 4 9275 Clamp-On AC Sensor 35

4.1 Product Specifications 35

Chapter 5 9276 Clamp-On AC/DC Sensor 39

5.1 Product Specifications 39

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ntroduction

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Thank you for purchasing this Hioki 3270 Current
Monitor. In order to use this product effectively and to
ensure that it enjoys a long operational life, read this
Instruction Manual carefully and then retain it for future
reference.

otes on Safety

1

WARNIN

This instrument is designed to prevent accidental
shock to the operator when properly used. However
no engineering design can render safe an instrument
which is used carelessly. Therefore, this manual
must be read carefully and completely before making
any measurement. Failure to follow directions can
result in a serious of fatal accident.

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Safety Symbols

This Instruction Manual provides information and
warnings essential for operating this equipment in a safe
manner and for maintaining it in safe operating
condition. Before using this equipment, be sure to
carefully read the following safety notes.

This symbol is affixed to locations on the equipment
where the operator should consult corresponding
topics in this manual (which are also marked with the

symbol) before using relevant functions of the
equipment.
In the manual, this mark indicates explanations
which it is particularly important that the user read
before using the equipment.

This symbol denotes a ground terminal.

This symbol denotes a fuse.

DANGE

WARNIN

CAUTIO

NOTE

The following symbols are used in this Instruction
Manual to indicate the relative importance of cautions
and warnings.

Indicates that incorrect operation presents extreme
danger of accident resulting in death or serious
injury to the user.

Indicates that incorrect operation presents
significant danger of accident resulting in death or
serious injury to the user.

Indicates that incorrect operation presents
possibility of injury to the user or damage to the
equipment.

Denotes items of advice related to performance of
the equipment or to its correct operation.

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nspection

P

When the unit is delivered, check and make sure that it
has not been damaged in transit. In particular, check the
accessories, panel switches, and connectors.
If the unit is damaged, or fails to operate according to the
specifications, contact your dealer or Hioki representative.

recautions

In order to ensure safe operation and to obtain maximum
performance from the unit, observe the cautions listed
below.

3

CAUTIO

• Do not subject the unit to vibrations or shocks during
transport or handling. Be especially careful to avoid
dropping the unit.

• Do not store the unit where it will be exposed to direct
sunlight, high temperature, high humidity, or
condensation. If exposed to such conditions, the unit
may be damaged, the insulation may deteriorate, and
the unit may no longer satisfy its specifications.

• Before using the unit, inspect it and check the operation
to make sure that the unit was not damaged due to
poor storage or transport conditions. If damage is
found, contact your dealer or Hioki representative.

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Current Monitor (3270)

WARNIN

CAUTIO

CAUTIO

This unit is designed to be grounded through the
three-wire power cord provided. In order to prevent
electric shock, etc., connect this power cord to a
grounded three-prong power receptacle.
Before using a three-prong adapter, be sure to
connect the green wire from the adapter to ground.

• When unplugging the power cord from the power
receptacle or from the unit, grasp the plug, not the cord
in order to avoid damaging the cable.

• Several volts are generated at the output terminal when

the power is turned on or turned off.

Clamp-On Sensor

• If there is any type of dust or dirt on the core contact
surfaces, measurements may be affected. Wipe it
away gently with a soft cloth.

• Do not apply any sort of mechanical impact to the core
section. Scratches on the core surfaces will make
accurate measurements impossible.

• Do not bend or pull the sensor cables (especially where
the cable connects to the sensor) in order to avoid
damaging the sensor cables.

• When the power for the 3270 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.)

• Taking the sensor apart may damage the open-close
mechanism that could result in an inoperative unit.

1

3270 Current Monito

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.1 Product Overview

This monitor is a seven-range amp designed especially for
the 9273, 9274, 9275, and 9276 clamp-on sensors. When
used in conjunction with any of the four sensors and
connected to a recorder, oscilloscope, etc., this unit can be
used to easily record and monitor current waveforms.

5

Chapter

Chapter 1 3270 Current Monitor

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1

.2 Identification of Indicators

Filter
switc

ouplin

witch

Connecto

Ranges Range switc

Output terminals

(Johnson terminals

Fr on t Rea

Power supply connecto

Overload
indicators

Demagnetizing
switch

Fuse holde

Power ON

Power switc

Power OFF

Zero
adjustment
dial

Ground terminal

Output termina

(BNC terminal)

.3 Product Specifications

(Accuracy is guaranteed at 23°C± 3°° °C after the power has
been on for 30 minutes)

♦ Compatible sensors 9273, 9274, 9275, 9276
♦ Output voltage 1 V/range (front: Johnson

♦ Measurement ranges 0.1/0.2/0.5/1/2/5/10 A

(when using the 9273 or 9274)

1/2/5/10/20/50/100 A

Chapter 1 3270 Current Monitor

(when using the 9275 or 9276)

terminals; rear: BNC terminal)

♦

Zero adjustment When the 9274 or 9276 is

connected

♦ Demagnetizing When the 9274 or 9276 is

connected

♦ Filter functions Switchable on/off (cutoff

frequency is 100 kHz± 10 %)

♦ Coupling function Switchable AC/DC
♦ Overload indicators Turn on for each range when

input is exceeded by factor of

5.5

♦ Amplitude accuracy ± 0.5 %rdg.± 0.05 %f.s. up to

100 % input for range (DC, 45
to 66 Hz)

± 1.2 %rdg. up to 200 % input

for range (DC, 45 to 66 Hz)

♦ Frequency band AC: 0.2 Hz to 10 MHz (-3 dB)

DC: DC to 10 MHz (-3 dB)
(see Figure 1)

♦ Noise 10 mVrms or less (when using

filter: 2 mVrms or less) (with a
voltmeter for up to 20 MHz)

♦ Temperature ± 0.1 %/° C or less

characteristics

♦ Crest factor 5.5 or less versus the range

value

7

♦ Output resistance 50Ω
♦ Operating temperature 0to40°C , 80 % RH or less

and humidity (no condensation)

♦ Storage temperature -10 to 50° C, 80 % RH or less

and humidity (no condensation)

♦ Dielectric strength 1500 V AC for one minute

(between power supply and case,
and between power supply and
output terminal)

♦ Insulation resistance 500 V DC, 100 MΩ or more

(between power supply and case,
and between power supply and
output terminal)

Chapter 1 3270 Current Monitor

8

Figure 1 Frequency Band (example of characteristics)

♦ Power supply 100 V AC (50 /60 Hz) (120, 220,

and 240 V require specification)

♦ Power consumption 15 VA max.
♦ External dimensions Approx. 80(W)X 125(H)X

260(D) mm

♦ Mass Approx. 1,750 g
♦ Accessories Power cord, instruction manual,

spare fuse (F1.0 A/250 V,

20 mmX 5 mm dia., in the fuse

holder), 9177 Output cord

At range f.s. input

Coupling : DC

Output (dB, 0dB=1V)

Coupling : AC

Frequency (Hz)

Chapter 1 3270 Current Monitor

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.4 Measurement Procedure

1

Before taking measurements, prepare this unit, the
sensor and the other measuring equipment such as a
recorder and an oscilloscope.

.4.1 Preparation

9

CAUTIO

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 unit.

(1) Turn the power switch off and connect the power cord.
(2) Connect the sensor to be used to the connector on the

unit.

(3) Turn the power switch on and confirm that the power

indicator lights.

(4) Connect the output terminal on the unit and the input

terminal of the measuring equipment, such as a recorder.
(When using an oscilloscope, make the connections so that
the GND terminal for the probe is connected to the L
output terminal.)

Chapter 1 3270 Current Monitor

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.4.2 Measurement

DANGE

CAUTIO

To avoid short circuits and accidents that could
result in injury or death, use clamp testers only with
power lines carrying 600 V AC or less.
To avoid short circuits and accidents that could
result in injury or death, when the tip of jaws is
open, do not use on bare conductors. The core
and shield case are not insulated.

• Do not exceed the maximum allowable current input.
The maximum input range differs, depending on the
frequency of measured current. (Refer to specifications
of the sensor.)

• If current exceeds the maximum allowable input,
overheating of the sensor will trip the protective function
for the internal circuitry, so the unit will no longer
produce accurate output. If this happens, eliminate the
input immediately (either by removing the sensor from
the conductor being measured or by reducing the input
current to zero.) (Wait until the sensor has had
sufficient time to cool before resuming operation.)

• If the above situation occurs repeatedly, or if current in
excess of the maximum input range is input
continuously, the sensor could be damaged.

• Be sure to press only one range switch; avoid having
none of the LEDs that indicate the range lit, or having
two or more lit at the same time.

Chapter 1 3270 Current Monitor

11

C

"OPEN" indication

Facing surface

Lever

Core section

Sensor connector

Sensor cable

Figure 2 9273 Identification of Indicators

1

NOTE

• Depending on the measured current value and the
frequency, however, some sound may be produced by
resonation from the sensor, it has no effect on
measurements.

• If a circuit carrying a large current is near to the sensor,
measurements may be affected by external magnetic
fields.

.4.2.1 When Using the 9273

urrent direction mark "UNLOCK" indication

NOTE

(1) Select both ranges of the 3270 and the measuring

equipment according to the input current value. (Refer to
Table 1 in Section 1.4.3.3.)

(2) Set the coupling switch to AC.
(3) Pull the lever of the sensor towards the "OPEN"

indication to open the core section. (Refer to Figure 2,
9273 Identification of Indicators.)

(4) Position the sensor so that the current direction mark on

the sensor part points in the direction of the load and so
that the conductor being measured is centered, and then
close the core section with the lever.

If the conductor being measured is not centered, the
results may be affected by its position.

Chapter 1 3270 Current Monitor

12

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Lock state

NOTE

(5) Press the lever forward until the "UNLOCK" indication

disappears, and confirm that the lever is completely
locked.

Accurate measurement is not possible if "UNLOCK" is
visible.

(6) The current waveform can now be recorded or monitored

with the measuring equipment.

CAUTIO

NOTE

When opening the core section of the sensor, be sure to
operate with the lever. If an upper core is forced to open
when the sensor is locked, the open-close mechanism
can be damaged.

o not pres

• To eliminate noise and other high-frequency components,
set the filter switch to "ON". (The cutoff frequency is
approximately 100 kHz.)

• If it is necessary to go to 0.2 Hz or less, outside of the
frequency band, then set the coupling to DC. (The offset
voltage value for this unit is weighted as the DC
component. The offset voltage values changes, depending
on the range.)

• Immediately after the power is turned on and open or
close sensor, depending on the condition of the internal
circuitry, the output waveform will fluctuate up and down
for approximately several ten seconds until it stabilizes.
(However, a small amount of fluctuation will remain.)

• Accurate measurements are not possible when measuring
overlapping DC components of several amperes or more.

• The zero adjustment dial does not function.

Chapter 1 3270 Current Monitor

Facing surface

Lever

Core section

Sensor connector

Sensor cable

C

"OPEN" indication

Figure 3 9274 Identification of Indicators

1

• If the demagnetizing switch is pressed during
measurement, the output changes for approximately 1
second, but afterwards the measured value is not affected.
(The demagnetizing function is not used when an AC
sensor is connected.)

.4.2.2 When Using the 9274

urrent direction mark "UNLOCK" indication

13

(1) Select both ranges of the 3270 and the measuring

equipment according to the input current value. (Refer to
Table 1 in Section 1.4.3.3.)

(2) Set the coupling switch to DC.
(3) Adjust the GND level of the measuring equipment

(oscilloscope, etc.).

(4) Set the measuring equipment for DC coupling.
(5) Before clamping the sensor to the conductor to be

measured, press the demagnetizing switch.

(6) Turn the zero adjustment dial and adjust the output

voltage to zero (GND level).

(7) Pull the lever of the sensor towards the "OPEN"

indication to open the core section. (Refer to Figure 3,
9274 Identification of Indicators.)

Chapter 1 3270 Current Monitor

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Lock state

(8) Position the sensor so that the current direction mark on

the sensor part points in the direction of the load and so
that the conductor being measured is centered, and then
close the core section with the lever.

NOTE

If the conductor being measured is not centered, the
results may be affected by its position.

(9) Press the lever forward until the "UNLOCK" indication

disappears, and confirm that the lever is completely
locked.

NOTE

Accurate measurement is not possible if "UNLOCK" is
visible.

(10) The current waveform can now be recorded or monitored

with the measuring equipment.

CAUTIO

NOTE

When opening the core section of the sensor, be sure to
operate with the lever. If an upper core is forced to open
when the sensor is locked, the open-close mechanism
can be damaged.

o not pres

• To eliminate noise and other high-frequency components,
set the filter switch to "ON". (The cutoff frequency is
approximately 100 kHz.)

• If the coupling of this unit is set to AC, or the coupling of
the measuring equipment is set to AC, then components
below the respective cutoff frequencies will be attenuated.

• Immediately after powering on, there may in some cases
be a large offset drift caused by self-generated heat from
this unit and the sensor.

Chapter 1 3270 Current Monitor

• When performing continuous measurements, it is
necessary to be aware that the offset voltage for this unit
and the sensor drifts, depending on factors such as the
ambient temperature.

• Always perform demagnetizing and the zero adjustment
when taking measurements.

• The offset voltage value for this unit changes according to
the range. If you change the range, be sure to perform
the zero adjustment again.

• Perform the zero adjustment when there is no input and
after performing demagnetizing. (The coupling setting
must also be set to DC coupling.)

• Do not press the demagnetizing switch during
measurement. (If the switch is pressed, the output will
change for approximately 1 second. If you press the
switch inadvertently, perform demagnetizing and zero
adjustment again.)

• Before doing low current measurement, demagnetize the
sensor heads and zero-adjust as follows. After opening
and closing the sensor heads, the zero point may drift by
an amount equivalent to several mA.

1. Press the demagnetizing switch of the 3270.

2. Open and close the sensor head clamps two or three

times.

3. Turn the zero adjustment dial of the 3270 to zero the

output voltage.

15

Chapter 1 3270 Current Monitor

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Figure 4 9275 Identification of Indicators

1

.4.2.3 When Using the 9275

Current direction mar

Lever

Facing surfac

Core sectio

Sensor connecto

(1) Select both ranges of the 3270 and the measuring

equipment according to the input current value. (Refer to
Table 2 in Section 1.4.3.3.)

(2) Set the coupling switch to AC.
(3) Gently press the lever of the sensor to open the core

section. (Refer to Figure 4, 9275 Identification of
Indicators.)

(4) Position the sensor so that the current direction mark

points in the direction of the load and so that the
conductor being measured is centered, and then close the
core section.

NOTE

If the conductor being measured is not centered, the
results may be affected by its position.

Sensor cabl

Chapter 1 3270 Current Monitor

NOTE

NOTE

17

(5) Confirm that the lever is completely locked.

Accurate measurement is not possible if the sensor is not
locked.

(6) The current waveform can now be recorded or monitored

with the measuring equipment.

• To eliminate noise and other high-frequency components,
set the filter switch to "ON". (The cutoff frequency is
approximately 100 kHz.)

• If it is necessary to go to 0.2 Hz or less, outside of the
frequency band, then set the coupling to DC. (The offset
voltage value for this unit is weighted as the DC
component. The offset voltage values changes, depending
on the range.)

• Immediately after the power is turned on and open or
close sensor, depending on the condition of the internal
circuitry, the output waveform will fluctuate up and down
for approximately several ten seconds until it stabilizes.
(However, a small amount of fluctuation will remain.)

• Accurate measurements are not possible when measuring
overlapping DC components of ten and several amperes or more.

• The zero adjustment dial does not function.

• If the demagnetizing switch is pressed during

measurement, the output changes for approximately 1
second, but afterwards the measured value is not affected.
(The demagnetizing function is not used when an AC
sensor is connected.)

Chapter 1 3270 Current Monitor

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Figure 5 9276 Identification of Indicators

1

.4.2.4 When Using the 9276

Current direction mar

Lever

Facing surfac

Core sectio

Sensor connecto

(1) Select both ranges of the 3270 and the measuring

equipment according to the input current value. (Refer to

Table 2 in Section 1.4.3.3.)
(2) Set the coupling switch to DC.
(3) Adjust the GND level of the measuring equipment

(oscilloscope, etc.).
(4) Set the measuring equipment for DC coupling.
(5) Before clamping the sensor to the conductor to be

measured, press the demagnetizing switch.
(6) Turn the zero adjustment dial and adjust the output

voltage to zero (GND level).
(7) Gently press the lever of the sensor to open the core

section. (Refer to Figure 5, 9276 Identification of

Indicators.)

Sensor cabl

Chapter 1 3270 Current Monitor

(8) Position the sensor so that the current direction mark

points in the direction of the load and so that the
conductor being measured is centered, and then close the
core section.

NOTE

If the conductor being measured is not centered, the
results may be affected by its position.

(9) Confirm that the lever is completely locked.

NOTE

Accurate measurement is not possible if the sensor is not
locked.

(10) The current waveform can now be recorded or monitored

with the measuring equipment.

NOTE

• To eliminate noise and other high-frequency components,
set the filter switch to "ON". (The cutoff frequency is
approximately 100 kHz.)

• If the coupling of this unit is set to AC, or the coupling of
the measuring equipment is set to AC, then components
below the respective cutoff frequencies will be attenuated.

• Immediately after powering on, there may in some cases
be a large offset drift caused by self-generated heat from
this unit and the sensor.

• When performing continuous measurements, it is
necessary to be aware that the offset voltage for this unit
and the sensor drifts, depending on factors such as the
ambient temperature.

• Always perform demagnetizing and the zero adjustment
when taking measurements.

• The offset voltage value for this unit changes according to
the range. If you change the range, be sure to perform
the zero adjustment again.

• Perform the zero adjustment when there is no input and
after performing demagnetizing. (The coupling setting
must also be set to DC coupling.)

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Chapter 1 3270 Current Monitor

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• Do not press the demagnetizing switch during
measurement. (If the switch is pressed, the output will
change for approximately 1 second. If you press the
switch inadvertently, perform demagnetizing and zero
adjustment again.)

.4.3 Explanation of Each Function

.4.3.1 Connector

Connect any one of clamp-on sensors (9273 through 9276)
to the connector.

CAUTIO

• In order to prevent damages of this unit and the sensor
never plug in or unplug the sensor connector when the
power is turned on.

• Because± 12 V is output from the connector on the
equipment to provide power to the sensor, do not plug
anything into this connector except for the sensor
connector.

.4.3.2 Output Terminals

Output terminals are located on both the front and rear
of the unit; signals are output from these terminals
simultaneously.
Front: Johnson terminals (connect a shielded cord)
Rear: BNC terminal
The output resistance is approximately 50Ω..

CAUTIO

In order to prevent malfunctions, do not short the output
terminal or input voltage to them.

Chapter 1 3270 Current Monitor

21

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NOTE

• Connect measuring equipment with an input resistance of
at least 1 MΩ.. When using the front and rear panel
output terminals at the same time, make sure that the
combined input resistance of both measuring equipments
is 1 MΩ or more. (Accuracy is not guaranteed if the
input resistance is less than 1 MΩ.)

• Note that the frequency band is not guaranteed if the
load capacitance (the input capacitance of the measuring
equipment and the capacitance of the output cord) is
several hundred pF or more.

• Do not connect the GND terminal (L) of a recorder or an
oscilloscope to the H terminal on this unit. (Accurate
measurement may not be possible.)

.4.3.3 Measurement ranges

The measurement ranges differ according to the sensor
that is connected. (When a sensor is connected, the LED
indicating the range lights.)
When using the 9273 or 9274: 0.1/0.2/0.5/1/2/5/10 A
When using the 9275 or 9276: 1/2/5/10/20/50/100 A
In each measurement scale, output of 1V is generated
when input is at the top of the scale.
Determine the range to be set based on this unit’s
measurement ranges and the range of the measuring
equipment (such as a recorder) being used. (Refer to
Tables 1 and 2.)

CAUTIO

Be sure to press only one range switch; avoid having
none of the LEDs that indicate the range lit, or having two
or more lit at the same time.

Chapter 1 3270 Current Monitor

22

Table 1. Current value conversion table when the 9273 or 9274 (5 mm

Table 2. Current value conversion table when the 9275 or 9276 (20 mm

dia. type) is connected

Measuring
equipment
range/DIV

10 A range 0.1 A 0.2 A 0.5 A 1A 2A 5A 10 A 20 A
5 A range 0.05 A 0.1 A 0.25 A 0.5 A 1A 2.5 A 5A 10 A
2 A range 0.02 A 0.04 A 0.1 A 0.2 A 0.4 A 1A 2A 4A
1 A range 0.01 A 0.02 A 0.05 A 0.1 A 0.2 A 0.5 A 1A 2A

0.5 A range 5mA 0.01 A 0.025 A 0.05 A 0.1 A 0.25 A 0.5 A 1A

0.2 A range 2mA 4mA 0.01 A 0.02 A 0.04 A 0.1 A 0.2 A 0.4 A

0.1 A range 1mA 2mA 5mA 0.01 A 0.02 A 0.05 A 0.1 A 0.2 A

10 mV 20 mV 50 mV 100 mV 200 mV 500 mV 1V 2V

*The values indicate the current value per DIV of the

measuring equipment, such as a recorder.

dia. type) is connected

Measuring
equipment

range/DIV

100 A range 1A 2A 5A 10 A 20 A 50 A 100 A 200 A

50 A range 0.5 A 1A 2.5 A 5A 10 A 25 A 50 A 100 A
20 A range 0.2 A 0.4 A 1A 2A 4A 10 A 20 A 40 A

10 A range 0.1 A 0.2 A 0.5 A 1A 2A 5A 10 A 20 A

5 A range 0.05 A 0.1 A 0.25 A 0.5 A 1A 2.5 A 5A 10 A
2 A range 0.02 A 0.04 A 0.1 A 0.2 A 0.4 A 1A 2A 4A

1 A range 0.01 A 0.02 A 0.05 A 0.1 A 0.2 A 0.5 A 1A 2A

10 mV 20 mV 50 mV 100 mV 200 mV 500 mV 1V 2V

*The values indicate the current value per DIV of the

measuring equipment, such as a recorder.

Chapter 1 3270 Current Monitor

1

.4.3.4 Demagnetizing (DEMAG)

1

Because demagnetizing is necessary after range settings
when an AC/DC sensor (9274 or 9276) is connected, be
sure to press the demagnetizing switch. (Press the switch
when there is no input.)
Demagnetization is performed because there is a
possibility the sensor will become magnetized when the
power for the main unit is turned on/off or as the result of
excessive input. (Accurate measurements are not possible
if the sensor is magnetized.)
Demagnetization occurs in less than 1 second. In
addition, because the signal lines are disconnected by
internal circuitry during the demagnetization process, the
output voltage changes.
If you inadvertently press the demagnetizing switch while
taking a measurement, perform the demagnetizing
process again while there is no input.

23

NOTE

• Always demagnetize before performing the zero
adjustment.

• Because demagnetizing is only effective when an AC/DC
sensor is connected, the demagnetizing function does not
work when there is no sensor connected or when an AC
sensor (9273 or 9275) is connected.

.4.3.5 Zero adjustment (ZERO ADJ.)

When an AC/DC sensor (9274 or 9276) is connected,
demagnetizing and zero adjustment are necessary after
setting the range. (Perform zero adjustment while there is
no input.)
Zero adjustment is performed in order to compensate for
the offset voltage values of the unit and the sensors and
for the drift of those values caused by the temperature.

Chapter 1 3270 Current Monitor

24

1

1

Even when using an AC/DC sensor and setting the
coupling to AC for measurement, first set the coupling to
DC and perform the demagnetizing and zero adjustment
procedures.
Turning the zero adjustment dial to the left decreases the
output voltage, and turning the dial to the right increases
the output voltage. (The lower the measurement range,
the broader the zero adjustment range becomes. )

NOTE

Because zero adjustment is only effective when an AC/DC
sensor is connected, the zero adjustment function does not
work when there is no sensor connected or when an AC
sensor (9273 or 9275) is connected.

.4.3.6 Coupling (COUPLING)

The coupling method can be either AC or DC.
AC: Eliminates the DC component and outputs only the

AC signal. (The cutoff frequency is 0.2 Hz.)

DC: Outputs all signals.
Pressing the coupling switch sets the coupling to AC.

(The LED lights.)

.4.3.7 Filter (FILTER)

Use the filter to eliminate noise and other high-frequency
components. (The cutoff frequency is approximately 100
kHz.)
Pressing the filter switch turns the filter on. (The LED
lights.)

Chapter 1 3270 Current Monitor

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.4.3.8 Overload indicator (OVERLOAD)

1

This LED lights when the input (peak value) exceeds the
range by a factor of 5.5.
When the LED is lit, the input exceeds the crest factor
(maximum of 5.5 for each range value), resulting in
waveform distortion. Adjust the range so that the LED
goes off.

25

CAUTIO

NOTE

In order to avoid malfunctions, confirm the maximum
measurable current range of the sensor being connected
before beginning to take measurements. (Refer to
specifications of the sensor.)

The LED may light immediately after an AC sensor (9273
or 9275) is connected or depending on the position of the
zero adjustment dial when an AC/DC sensor (9274 or

9276) is connected.

.5 Fuse Replacement

If the fuse blows, replace it as shown in Figure 6.

WARNIN

In order to prevent electric shock, always
disconnect the power cord from the receptacle
before replacing the fuse.
Always replace the fuse with a new fuse of the
specified rating.
Never use a fuse of other than the specified rating,
and never short circuit the fuse holder to prevent an
accident resulting in injury or death.
100 V, 120 V : F1.0 A/250 V 20 mmX 5 mm dia.
220 V, 240 V : F0.5 A/250 V 20 mmX 5 mm dia.

Chapter 1 3270 Current Monitor

26

Spare fuse

Fuse holder

Power cord

Figure 6 Fuse Replacement

1. Unplug the power cord.

2. Remove the fuse holder, check the fuse and then
replace.

Chapter 1 3270 Current Monitor

2

9273 Clamp-On AC Senso

r

2

.1 Product Specifications

(Accuracy is guaranteed at 23°C± 3°C after the power has
been on for 30 minutes)

♦ Rated current 20AAC
♦ Output voltage 2 V AC/20 A AC
♦ Output resistance 50Ω
♦ Input impedance 0.1 mΩ or less at 55 Hz

(see Figure 7)

♦ Continuous maximum 20 A (see Figure 8)

input range

27

Chapter

♦ Maximum peak current 50 A noncontinuous (peak value)

value

♦ Amplitude accuracy ± 0.5 % rdg.± 0.05 % f.s.

(45 to 66 Hz)

♦ Phase accuracy ± 0.2° (45 to 66 Hz)
♦ Frequency band 0.7 Hz to 10 MHz (-3dB)

(see Figure 9, example of

characteristics)

♦ Frequency characteristics 2 Hz to 10 kHz:± 2.0 % or less

(Deviation from accuracy) 10 kHz to 100 kHz:± 3.0 % or less

♦ Temperature coefficient ± 0.1 % f.s./° C or less

for sensitivity (within a range of 0 to 40° C)

♦ Noise 1 mV rms or less (with a

voltmeter for up to 20 MHz)

♦ Power consumption 1.5 VA max. (with rated input)

Chapter 2 9273 Clamp-On AC Sensor

28

♦ Supply voltage ± 12 V± 1V
♦ Operating temperature 0to40°C , 80 % RH or less

and humidity (no condensation)

♦ Storage temperature -10 to 50°C , 80 % RH or less

and humidity (no condensation)

♦ Effect of external Equivalent to a maximum of

magnetic fields 20 mA (in a 400 A/m AC current

magnetic field)

♦ Effect of conductor Within± 0.2 %

position

♦ Dielectric strength 2200 V AC for 1 minute

(between electric circuit and case)

♦ Insulation resistance 500 V DC, 100 MΩ or more

(between electric circuit and case)

♦ Maximum permitted 600 V peak; (the core, shield

circuit voltage case, and electrical circuits are
(insulated conductor) not insulated.)

♦ Diameter of measurable 5 mm dia.

conductors

♦ Cord length Approx. 1.5 m
♦ External dimensions Approx. 175 (W)X 40 (H)X 18

and mass (D) mm, approx. 170 g

♦ Accessories Instruction manual, soft case

Chapter 2 9273 Clamp-On AC Sensor

29

)

)

Figure 7 9273 Input Impedance

)

Figure 8 9273 Maximum Input Range

)

)

e

Figure 9 9273 Frequency Band (example of characteristics)

Input impedance (mΩ

Frequency (Hz

Maximum input current (A rms)

Frequency (Hz

Amplitud

plitude

B, 0dB=1 V

Amplitude (dB, 0dB=1V)

Phase

Frequency (Hz

Chapter 2 9273 Clamp-On AC Sensor

Phase (deg.)

30

Chapter 2 9273 Clamp-On AC Sensor31Chapter 3 9274 Clamp-On AC/DC Sensor

3

9274 Clamp-On AC/D

C

r

3

.1 Product Specifications

(Accuracy is guaranteed at 23 ° C ± 3 °C after the power has
been on for 30 minutes)

♦ Rated current 20 A (AC+DC)
♦ Output voltage 2 V /20 A (AC+DC)
♦ Output resistance 50Ω
♦ Input impedance 0.1 mΩ or less at 55 Hz

(see Figure 10)

♦ Continuous maximum 20 A (see Figure 11)

input range

♦ Maximum peak current 50 A noncontinuous (peak value)

value

Chapter

Senso

♦ Amplitude accuracy ± 0.5 % rdg.± 0.1 % f.s.

(DC, 45 to 66 Hz)

♦ Phase accuracy ± 0.2° (45 to 66 Hz)
♦ Frequency band DC to 10 MHz (-3 dB) (see Figure

12, example of characteristics)

♦ Frequency characteristics DC to 1 kHz:± 2.0 % or less

(Deviation from accuracy) 1 kHz to 100 kHz:± 5.0 % or less

♦ Temperature coefficient ± 0.1 % f.s./°C or less

for sensitivity (within a range of 0 to 40°C )

♦ Noise 1 mV rms or less (with a

voltmeter for up to 20 MHz)

32

♦ Power consumption 1.5 VA max. (with rated input)
♦ Supply voltage ± 12 V± 1V
♦ Operating temperature 0to40 ° C, 80 % RH or less

and humidity (no condensation)

♦ Storage temperature -10 to 50 ° C, 80 % RH or less

and humidity (no condensation)

♦ Effect of external Equivalent to a maximum of

magnetic fields 20 mA (in a 400 A/m AC current

magnetic field)

♦ Effect of conductor Within± 0.2 %

position

♦ Dielectric strength 2200 V AC for 1 minute

(between electric circuit and case)

♦ Insulation resistance 500 V DC, 100 MΩ or more

(between electric circuit and case)

♦ Maximum permitted 600 V peak; (the core, shield

circuit voltage case, and electrical circuits are
(insulated conductor) not insulated.)

♦ Diameter of measurable 5 mm dia.

conductors

♦ Cord length Approx. 1.5 m
♦ External dimensions Approx. 175 (W)X 40 (H)X 18

and mass (D) mm, approx. 170 g

♦ Accessories Instruction manual, soft case

Chapter 3 9274 Clamp-On AC/DC Sensor

33

)

)

Figure 10 9274 Input Impedance

)

Figure 11 9274 Maximum Input Range

)

)

e

Figure 12 9274 Frequency Band (example of characteristics)

Input impedance (mΩ

Frequency (Hz

Maximum input current (A rms)

Frequency (Hz

Amplitud

plitude

B, 0dB=1 V

Amplitude (dB, 0dB=1V)

Phase

Frequency (Hz

Chapter 3 9274 Clamp-On AC/DC Sensor

Phase (deg.)

34

Chapter 3 9274 Clamp-On AC/DC Sensor35Chapter 4 9275 Clamp-On AC Sensor

4

9275 Clamp-On AC Senso

r

4

.1 Product Specifications

(Accuracy is guaranteed at 23°C± 3°C after the power has
been on for 30 minutes)

♦ Rated current 150 A AC
♦ Output voltage 1.5 V AC/150 A AC
♦ Output resistance 50Ω
♦ Input impedance 0.02 mΩ or less at 55 Hz

(see Figure 13)

♦ Continuous maximum 150 A (see Figure 14)

input range

♦ Maximum peak 400 A noncontinuous

current value (peak value)

Chapter

♦ Amplitude accuracy ± 0.5 % rdg.± 0.05 % f.s.

(45 to 66 Hz)

♦ Phase accuracy ± 0.2
♦ Frequency band 0.5 Hz to 1 MHz (-3 dB) (see

♦ Frequency characteristics 1Hzto10Hz:± 3.0 % or less

(Deviation from accuracy) 10 Hz to 10 kHz :± 1.0 % or less

10 kHz to 100 kHz:± 3.0 % or

♦ Temperature for ± 0.05 % f.s./°C or less

sensitivity (within a range of 0 to 40°C )

♦ Noise 1 mV rms or less (with a

(45 to 66 Hz)

Figure 15, example of
characteristics)

less

voltmeter for up to 20 MHz)

36

♦ Power consumption 2 VA max. (with rated input)
♦ Supply voltage ± 12 V± 1V
♦ Operating temperature 0to40°C , 80 % RH or less

and humidity (no condensation)

♦ Storage temperature -10 to 50°C , 80 % RH or less

and humidity (no condensation)

♦ Effect of external Equivalent to a maximum of 1 A

magnetic fields (in a 400 A/m AC current

magnetic field)

♦ Effect of conductor Within± 1%

position

♦ Dielectric strength 2200 V AC for 1 minute

(between electric circuit and case)

♦ Insulation resistance 500 V DC, 100 MΩ or more

(between electric circuit and case)

♦ Maximum permitted 600 V peak; (the core, shield

circuit voltage case, and electrical circuits are
(insulated conductor) not insulated.)

♦ Diameter of measurable 20 mm dia.

conductors

♦ Cord length Approx. 1.5 m
♦ External dimensions Approx. 145 (W)X 60 (H)X 33

and mass (D) mm, approx. 300 g

♦ Accessories Instruction manual, carrying

Chapter 4 9275 Clamp-On AC Sensor

case

37

)

)

Figure 13 9275 Input Impedance

)

Figure 14 9275 Maximum Input Range

)

e

Figure 15 9275 Frequency Band (Example of Characteristics)

Input impedance (mΩ

Frequency (Hz

Maximum input current (A rms)

Frequency (Hz

Phase

Amplitud

Amplitude (dB, 0dB=1V)

Frequency (Hz

Chapter 4 9275 Clamp-On AC Sensor

Phase (deg.)

38

Chapter 4 9275 Clamp-On AC Sensor39Chapter 5 9276 Clamp-On AC/DC Sensor

5

9276 Clamp-On AC/D

C

r

5

.1 Product Specifications

(Accuracy is guaranteed at 23°C ± 3°C after the power has
been on for 30 minutes)

♦ Rated current 150 A (AC+DC)
♦ Output voltage 1.5 V /150 A (AC+DC)
♦ Output resistance 50Ω
♦ Input impedance 0.02 mΩ or less at 55 Hz

(see Figure 16)

♦ Continuous maximum 150 A (see Figure 17)

input range

♦ Maximum peak 400 A noncontinuous

current value (peak value)

Chapter

Senso

♦ Amplitude accuracy ± 0.5 % rdg.± 0.1 % f.s.

(DC, 45 to 66 Hz)

♦ Phase accuracy ± 0.2
♦ Frequency band DC to 1 MHz (-3 dB) (see Figure

18, example of characteristics)

♦ Frequency characteristics DC to 10 kHz :± 2.0 % or less

(Deviation from accuracy) 10 kHz to 100 kHz :± 4.0 % or

less

♦ Temperature for ± 0.05 % f.s./°C or less

sensitivity (within a range of 0 to 40°C

(45 to 66 Hz)

40

♦ Noise 1 mV rms or less (with a

voltmeter for up to 20 MHz)

♦ Power consumption 2 VA max. (with rated input)
♦ Supply voltage ± 12 V± 1V
♦ Operating temperature 0to40°C , 80 % RH or less

and humidity (no condensation)

♦ Storage temperature -10 to 50°C , 80 % RH or less

and humidity (no condensation)

♦ Effect of external Equivalent to a maximum of 1 A

magnetic fields (in a 400 A/m AC current

magnetic field)

♦ Effect of conductor Within± 1%

position

♦ Dielectric strength 2200 V AC for 1 minute

(between electric circuit and case)

♦ Insulation resistance 500 V DC, 100 M Ω or more

(between electric circuit and case)

♦ Maximum permitted 600 V peak; (the core, shield

circuit voltage case, and electrical circuits are
(insulated conductor) not insulated.)

♦ Diameter of measurable 20 mm dia.

conductors

♦ Cord length Approx. 1.5 m
♦ External dimensions Approx. 145 (W)X 60 (H)X 33

and mass (D) mm, approx. 300 g

♦ Accessories Instruction manual, carrying

Chapter 5 9276 Clamp-On AC/DC Sensor

case

41

)

)

)

)

)

Figure 18 9276 Frequency Band (example of characteristics)

Input impedance (mΩ

Frequency (Hz

Figure 16 9276 Input Impedance

Maximum input current (A rms

Frequency (Hz

Figure 17 9276 Maximum Input Range

Amplitude (dB, 0dB=1V)

Phase

Amplitude

Frequency (Hz

Chapter 5 9276 Clamp-On AC/DC Sensor

Phase (deg.)

42

Chapter 5 9276 Clamp-On AC/DC Sensor