Hioki 3270 User manual

INSTRUCTION MANUAL
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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

1
WARNIN
G
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.
I
ntroduction
N
otes on Safety
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.

2
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
R
Indicates that incorrect operation presents extreme
danger of accident resulting in death or serious
injury to the user.
WARNIN
G
Indicates that incorrect operation presents
significant danger of accident resulting in death or
serious injury to the user.
CAUTIO
N
Indicates that incorrect operation presents
possibility of injury to the user or damage to the
equipment.
NOTE Denotes items of advice related to performance of
the equipment or to its correct operation.
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.
The following symbols are used in this Instruction
Manual to indicate the relative importance of cautions
and warnings.

3
CAUTIO
N
• 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.
I
nspection
P
recautions
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.
In order to ensure safe operation and to obtain maximum
performance from the unit, observe the cautions listed
below.

4
WARNIN
G
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.
CAUTIO
N
• 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.
CAUTIO
N
• 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.
Current Monitor (3270)
Clamp-On Sensor

5
Chapter 1 3270 Current Monitor
Chapter
1
3270 Current Monito
r
1
.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.

6
Chapter 1 3270 Current Monitor
C
ouplin
g
s
witch
Connecto
r
Ground terminal
Power supply connecto
r
Output terminals
(Johnson terminals
)
FrontRea
r
Filter
switc
h
Overload
indicators
Demagnetizing
switch
Zero
adjustment
dial
Ranges Range switc
h
Output termina
l
(BNC terminal)
Fuse holde
r
Power ON
Power switc
h
Power OFF
1
.2 Identification of Indicators
1
.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 1V/range (front: Johnson
terminals; rear: BNC terminal)
♦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
(when using the 9275 or 9276)

7
Chapter 1 3270 Current Monitor
♦ 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
♦ 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 VAC for one minute
(between power supply and case,
and between power supply and
output terminal)
♦ Insulation resistance 500 VDC, 100 MΩ or more
(between power supply and case,
and between power supply and
output terminal)

8
Chapter 1 3270 Current Monitor
Frequency (Hz)
Output (dB, 0dB=1V)
At range f.s. input
Coupling : DC
Coupling : AC
Figure 1 Frequency Band (example of characteristics)
♦ Power supply100 VAC (50 /60 Hz) (120, 220,
and 240 V require specification)
♦ Power consumption 15 VA max.
♦ External dimensions Approx. 80(W)X125(H)X
260(D) mm
♦ Mass Approx. 1,750 g
♦ AccessoriesPower cord, instruction manual,
spare fuse (F1.0 A/250 V,
20 mmX5mm dia., in the fuse
holder), 9177 Output cord

9
Chapter 1 3270 Current Monitor
CAUTIO
N
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
.4 Measurement Procedure
1
.4.1 Preparation
Before taking measurements, prepare this unit, the
sensor and the other measuring equipment such as a
recorder and an oscilloscope.
(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.)

10
Chapter 1 3270 Current Monitor
DANGE
R
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.
CAUTIO
N
• 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.
1
.4.2 Measurement

11
Chapter 1 3270 Current Monitor
NOTE
C
urrent direction mark "UNLOCK" indication
"OPEN" indication
Facing surface
Lever
Core section
Sensor connector
Sensor cable
Figure 2 9273 Identification of Indicators
NOTE
1
.4.2.1 When Using the 9273
• 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 acircuit carrying alarge current is near to the sensor,
measurements may be affected by external magnetic
fields.
(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.

12
Chapter 1 3270 Current Monitor
NOTE
CAUTIO
N
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.
D
o not pres
s
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.
• 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.

13
Chapter 1 3270 Current Monitor
Facing surface
Lever
Core section
Sensor connector
Sensor cable
C
urrent direction mark "UNLOCK" indication
"OPEN" indication
Figure 3 9274 Identification of Indicators
1
.4.2.2 When Using the 9274
• 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.)
(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.)

14
Chapter 1 3270 Current Monitor
NOTE
NOTE
CAUTIO
N
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.
D
o not pres
s
Lock state
NOTE
(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.
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.
Accurate measurement is not possible if "UNLOCK" is
visible.
(10) 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 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.

15
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.

16
Chapter 1 3270 Current Monitor
Facing surfac
e
Core sectio
n
Sensor connecto
r
Sensor cabl
e
Lever
Current direction mar
k
Figure 4 9275 Identification of Indicators
NOTE
1
.4.2.3 When Using the 9275
(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.
If the conductor being measured is not centered, the
results may be affected by its position.