INSTRUCTION MANUAL

HIGH VOLTAGE INSULATION TESTER

KEW 3127
 Contents

1Safety warnings 1
2Feature 5
3Specification 6
4Instrument layout 10
4-1 Instrument layout 10
4-2 LCD display 11
4-3 Opening and closing Hard case 12
4-4 Taking out KEW3127 from the Hard case 12
5. Preparation for measurement 13
5-1 Checking the battery voltage 13
5-2 Connecting test leads 13
6. Measurement 14
6-1 Mains disconnection check (Voltage measurement) 14
6-2 Insulation resistance measurement 15
6-3 About BREAKDOWN mode and BURN mode 19
6-4 Continuous measurement 20
6-5 IRPI/DAR Measurement 21
6-6 SV Measurement (Step Voltage) 27
6-7 DD Measurement (Dielectric Discharge) 28
6-8 Ramp Measurement 30
6-9 Voltage characteristics of measuring terminal 32
6-10 Use of Guard terminal 32
6-11 Filter function 33
6-12 Backlight function 33
6-13 Auto-power-off function 33
7. Memory function 34
7-1 Function details 34
7-2 How to save data 35
7-3 How to recall saved data 36
7-4 How to delete data 37
8Clock Setting 38
9. Communication Function/ Software 39
9-1 KEW3127 Settings 39
9-2 How to install the Software 42
9-3 How to start KEW Windows for KEW3127 45
9-4 Features of KEW Smart 47
10Battery Charging and Replacement 48
10-1 How to charge battery 48
10-2 How to replace battery 49
11Accessories 51
11-1 Metal part for Line Probe, and replacement 51
11-2 How to use the adaptor for recorder 52
11-3 Line probe with alligator clip 52
12. Disposing the Product 53
 1. Safety warnings

This instrument has been designed, manufactured and tested according to IEC
61010: Safety requirements for Electronic measuring apparatus, and delivered in
the best condition after passed the inspection. This instruction manual contains
warnings and safety rules which must be observed by the user to ensure safe
operation of the instrument and retain it in safe condition.
Therefore, read through these operating instructions before using the instrument.

# WARNING
Read through and understand instructions contained in this manual before
starting to use the instrument.
Save and keep the manual at hand to enable quick reference whenever
necessary.
The instrument is to be used only in its intended applications.
Understand and follow all safety instructions contained in the manual.
It is essential that the above instructions are adhered to. Failure to follow the
above instructions may cause injury, instrument damage and/or damage to
equipment under test.
Kyoritsu is by no means liable for any damage resulting from the instrument in
contradiction to this cautionary note.

The symbol # indicated on the instrument means that the user must refer to
related parts in the manual for safe operation of the instrument. It is essential to
read the instructions wherever the # symbol appears in the manual.

# DANGER is reserved for conditions and actions that are likely to cause
serious or fatal injury.
# WARNING is reserved for conditions and actions that can cause serious
or fatal injury.
# CAUTION is reserved for conditions and actions that can cause injury or
instrument damage.

－1－
 # DANGER
Never make measurement on the circuit in which electrical potential to
ground over 600V exists.
Do not attempt to make measurement in the presence of flammable gasses.
Otherwise, the use of the instrument may cause sparking, which can lead to
an explosion.
Never attempt to use the instrument if its surface or your hand is wet.
Be careful not to short-circuit the power line with the metal part of the test
leads when measuring voltage. It may cause personal injury.
Do not apply inputs exceeding the maximum allowable measuring range.
Do not press the Test button with test leads connected to the instrument.
Never open the battery compartment cover while making a measurement.
Do not touch the circuit under test while measuring insulation resistance or
right after a measurement. You may get an electric shock by a test voltage.
The instrument should be used only in its intended applications or conditions.
Otherwise, safety functions equipped with the instrument do not work, and
instrument damage or serious personal injury may be caused.
Keep your fingers and hands behind the protective fingerguard during
measurement.

# WARNING
Never attempt to make any measurement if any abnormal conditions are
noted, such as broken case and exposed metal parts or when inner jackets
are seen through the nicked outer jacket.
Do not rotate the Range switch with the test leads connected to the equipment
under test.
Do not install substitute parts or make any modification to the instrument.
Return the instrument to your local Kyoritsu distributor for repair or re-
calibration.
Do not try to replace the battery if the surface of the instrument is wet.
Firmly insert the plug into the terminal when using test leads.
Ensure that the instrument is powered off when opening the battery
compartment cover for battery replacement.
Stop using the test lead if the outer jacket is damaged and the inner metal
or color jacket is exposed.

－2－
 # CAUTION
Always make sure to set the Range switch to the appropriate position before
making a measurement.
Set the Range Switch to OFF position after use and disconnect the
test leads from the instrument. Remove the battery if the instrument is to be
stored and will not be used for a long period.
Do not expose the instrument to the direct sun, high temperature and
humidity or dewfall.
Use a cloth dipped in alcohol for cleaning the test leads and the part around
the measuring terminals.
Do not store the instrument if it is wet.
The Voltage warning mark is being displayed during a measurement and it
flashes when voltages 30V(DC/AC) or more exist on the circuit under test.

Symbols

 Danger of possible electric shock

 Instrument with double or reinforced insulation

 DC

 AC

 Earth terminal
Crossed-out wheel bin symbol (according to WEEE Directive: 2002/96/
EC) indicating that this electrical product may not be treated as
household waste, but that it must be collected and treated separately.

－3－
Measurement categories(Over-voltage categories)

To ensure safe operation of measuring instruments, IEC 61010 establishes safety

standards for various electrical environments, categorized as O to CAT IV, and
called measurement categories. Higher-numbered categories correspond to
electrical environments with greater momentary energy, so a measuring instrument
designed for CAT III environments can endure greater momentary energy than
one designed for CAT II.

O : Circuits which are not directly connected to the mains power supply.
CAT II : Electrical circuits of equipment connected to an AC electrical outlet by
a power cord.
CAT III : Primary electrical circuits of the equipment 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 device (distribution
panel).

O: Device which is
not directly
connected to the
mains power supply

－4－
2. Feature

KEW3127 is a microcomputer controlled, high voltage insulation resistance tester

with 5-range for measuring insulation resistance.

Designed to following safety standards:

IEC 61010-1 (CAT IV 600V Pollution degree 2)
IEC 61010-031 (Requirements for hand-held probes)
With auto-discharge function
When insulation resistance like a capacitive load is measured, electrical charges
stored in capacitive circuits are automatically discharged after measuring.
Discharge can be checked on the voltage monitor.
Backlight function to facilitate working at dimly illuminated location or at
nighttime work.
Bar graph to display measured result
LIVE circuit warning symbols plus audible warning
With Auto-power off function
To prevent the instrument being left powered on and conserve battery power,
the instrument automatically turns off approx. 10 min. after the last switch
operation.
Auto-measurement and display of PI (Polarization Index), DAR (Dielectric
Absorption Ratio) and DD (Dielectric discharge), Step Voltage (SV), leakage
current and capacitance measurements, and Ramp measurement for
breakdown voltage check.
Filter function to reduce the variations in readings due to external influences
With a short current of max 5mA, quick measurement is possible even if the
object under test has capacitive components.
Internal saved data and real-time measuring data can be transferred to a PC
via Bluetooth communication or by using special USB adapter (MODEL8212
USB). Easy settings for KEW3127 and data analysis via PC are possible with
the application software.

－5－
3. Specification

Applicable standards
IEC 61010-1 Measurement CAT IV 600V Pollution degree2
IEC 61010-031 Standard for hand-held probes
MODEL7165A(CAT IV 600V)
MODEL7224A(CAT IV 600V)
MODEL7225A(CAT IV 600V)
* When KEW3127 and the test lead are combined and
used together, whichever is lower category either of
them belong to is applied.
IEC 61326-2-2 EMC standard
IEC 60529 IP40(Instrument)
IP65 (Hard case)
EN 50581 RoHS

Measuring range and accuracy (Temperature, humidity: 23±5Cº, 45 - 75%RH)

<Insulation resistance tester>
Rated
250V(*1) 500V 1000V 2500V 5000V Accuracy
voltage
0.0-99.9M 0.0-99.9M
0.0-99.9M
0.0-99.9M 100-999M 100-999M ±5%rdg
0.0-99.9M 100-999M
100-999M 1.00-9.99G 1.00-9.99G ±3dgt
Measuring 1.00-1.99G
10.0-99.9G 10.0-99.9G
range(*2)
2.00-9.99G
100-999M 1.00-9.99G 100-999G
10.0-99.9G 100-999G ±20%rdg
1.00-9.99G 10.0-99.9G 1.00-9.99T
100-199G
Display range 0.0M - 12.00G 0.0M-120.0G 0.0M-240G 0.0M-1200G 0.0M-12.00T
Open circuit DC 250V DC 500V DC 1000V DC 2500V DC 5000V
voltage +10%, -10% +20%, -10% +20%, -0% +20%, -0% +20%, -0%
1mA or more, 1mA or more, 1mA or more,
Rated
1.2mA or less 1.2mA or less 1.2mA or less
current
(at 1M load) (at 2.5M load) (at 5M load)
Short-circuit For 10 sec after a test is started : max 5mA,
current after that : 1.4mA
(*1) 250V Range is for IRPI/DAR measurement only.
(*2) Measuring range goes to one lower range when the applied input drops to
80% or lower of the rating of the lower range. Measurement accuracy to be
applied is changed when the range goes to the lower range.

－6－
<Voltage monitor for insulation resistance range>
Rated voltage 250V 500V 1000V 2500V 5000V Accuracy
Measuring 30-330V 30-650V 30-1200V 30-3000V 30-6000V ±10%rdg±20V
range (resolution 10V)
This monitor is used to check whether electrical charge stored on the equipment
under test is discharged or not. The measured voltage value displayed on the
LCD is a reference value.
Please be noted that the indicated value, when external AC voltage is applied to
the instrument, is not the correct value.
<Volt meter >
Measuring range Resolution Accuracy

Volt DC voltage:±30 - ±600V

AC voltage: 30 - 600V 1V ±2%rdg±3dgt
(50/60Hz)
Frequency 45.0-65.0Hz(*1) 0.1Hz ±0.2Hz
(*1)When the measured voltage is less than 30V or DCV is measured, the
frequency is displayed as ----Hz on the LCD.
<Ammeter (Output Current)>
Measuring range Accuracy
0.00nA～5.50mA ±10%rdg(*1)
(*1)If result of resistance measurement is 10M or more, output current is
determined by resistance and voltage.(Accuracy is derived from measured
resistance specification and measured voltage specification)
<Capacity meter>
Rated voltage Measuring range Accuracy
250V 2500V range 5.0nF 50.0F
±5%rdg±5dgt
5000V range 5.0nF 25.0F
Calculated Value
PI,DAR,DD
Measurement Mode Display range Computational error
PI 0.00 9.99 ±2dgt
DAR 0.00 9.99 ±2dgt
DD 0.00 9.99 ±2dgt

－7－
Display: Liquid crystal display
Bar graph: Max. 41points
DAR/PI value: 9.99
Time: 99:59
Low battery warning: Battery mark display (in 4 levels)
Overrange indication: OL mark appears at insulation resistance
range and Hi mark at voltage range.
Auto-ranging: Range shifts to upper range : 1000 counts
Range shifts to lower range : 80 counts
(Only at the insulation resistance range)
Auto-power-off: Power off function operates in 10 min. after
the last switch operation.
Used location: altitude 2000 m or less
Temperature & humidity range (guaranteed accuracy):
23ºC±5ºC/Relative humidity 85% or less
(no condensation)
Operating temperature & humidity range:
0ºC to 40ºC/Relative humidity 85% or less
(no condensation)
Storage temperature & humidity range:
-20ºC to +60ºC/Relative humidity 75% or less
(no condensation)
Overload protection: Insulation resistance range: AC1200V/10sec.
Voltage range: AC720V/10sec.
Withstand voltage: AC6720V(50/60Hz)/5sec.
(Between electrical circuit and enclosure)
Insulation resistance: 1000M or more/DC1000V
(Between electrical circuit and enclosure)
Dimension: 208(L)×225(W)×130(D)mm
(Hard case 380(L)×430(W)×154(D)mm)
Weight: 4kg approx. (including battery)
Total 8kg approx. (including accessories)
Power source: Rechargeable battery
12V5Ah Lead acid batteries (PXL12050) or equivalent.
Power Adapter Output:DC15V(15VA)
for recharging Input:100-240V 50/60Hz

－8－
Current consumption (representative values at 12V of supply voltage)
Range 250V 500V 1000V 2500V 5000V VOLT
Output at For 10 sec after a test is started : 700mA,
short-circuit after that : 180mA
When rated
380mA 440mA 510mA 670mA 860mA
measuring current
/0.25M /0.5M /1M /2.5M /5M 110mA
is outputted
Output at
60mA 60mA 70mA 90mA 140mA
open circuit
On stand-by 30mA
When backlight
Increased by 30mA
is on

Note) Current values in above table are all approximate values.

Operating time: approx. 10 hours continuous

- under a load of 100M at 5000V Insulation resistance range
Accessories: Line probe: MODEL7165A
(Including MODEL8255 Straight type prod with molded parts)
Earth cord: MODEL7224A
Guard cord: MODEL7225A
Hard Case MODEL9171
Pickel Type Prod: MODEL8019
Straight Type Prod: MODEL8254
Instruction manual
Power Adapter

Optional accessories: USB Communication set:MODEL8258

(USB adaptor(MODEL8212USB) with KEW Windows for
3127)
Adaptor for recorder:MODEL8302
Line probe with alligator clip:MODEL7168A
Long Line probe with alligator clip (15m): MODEL7253

－9－
4. Instrument layout
4-1 Instrument layout
9

1
11 15
2 16
3 12
4
5 13
6
7

14
8
10
1 LCD display 17 18 19
2 MEMORY button
3 ENTER button
4 MODE button
5 ESC button
6 UP/DOWN button
7 FILTER button 21 21
8 TEST button
9 Backlight button
10 Range switch
11 Earth terminal
12 Guard terminal
13 Line terminal
14 Communication port
(for MODEL8212USB) 21
15 Shutter
16 Power adapter terminal 20
17 Earth cord (black)
18 Guard cord (green)
19 Line probe (red)
20 Power adapter
21 Protective fingerguard
It is a part providing protection against electrical shock and ensuring the
minimum required air and creepage distances.

－ 10 －
4-2 LCD display

11 12
1 10
2 13
14
3 15
4 16
5
17
6
7
8

9 18

1 Battery mark
2 Overheat warning mark
3 AC/DC mark
4 LOGGING mark
5 MEMORY mark
6 FILTER mark
7 Date and time mark
8 Time
9 DAR/PI/DD/Break down/Frequency value
10 Voltage warning mark
11 Bar graph
12 MODE mark
13 USB mark(for MODEL8212USB)
14 Bluetooth mark
15 Output voltage
16 Insulation resistance
17 Unit
18 Capacitance / Output current value

－ 11 －
4-3 Opening and closing Hard case
The Latching device has two features: the larger portion which is the latch itself ,
and the small latch release tab at the bottom of the latch.

①
1. To open, pull up the latch release tab
in the direction of the arrow. ②
2. To close, lower the latch and press
until it snaps.
Never press the latch release tab
to close the latch as damage may result.

4-4 Taking out KEW3127 from the Hard case.

Grip the handles and pull upward to take out KEW3127 from the Hard case.

Handles

－ 12 －
 5. Preparation for measurement
It is recommended to charge the battery with reference to 10.1 How to charge
battery described in the manual before stating to use with the instrument since
the battery voltage may be low due to self-discharge.

5-1 Checking the battery voltage

(1) Set the Range switch to any position other than OFF .
(2) When the battery mark shown at the upper left on the LCD is last 1 level ,
the batteries are almost exhausted.
Charge battery to perform further measurements.
The instrument operates properly even in such a low battery power condition
and it may not affect the accuracy.
When battery mark is empty , the battery voltage is below the lower limit
of the operating voltage. In such a condition, the accuracy isnt guaranteed.
Refer to10.1 How to charge battery and charge battery.

5-2 Connecting test leads

Insert the test lead firmly to the connector terminal on the instrument. Connect the
Line Probe(red) to the Line terminal, the Earth Cord(black) to the Earth terminal
and the Guard Cord(green) to the Guard terminal. (To establish guard is not
necessary, you do not have to connect the Guard cord.)

# DANGER
Do not press the TEST button when the Range switch is at any position other
than OFF . High voltages are applied to the test leads and you may get
electrical shocks.

# WARNING
Stop using the test lead if the outer jacket is damaged and the inner metal
or color jacket is exposed.

－ 13 －
6. Measurement
6-1 Mains disconnection check (Voltage measurement)

# DANGER
Do not make measurement on a circuit in which the electric potential
exceeds 600V (voltage to ground) in order to avoid getting electrical shock.
In addition, do not use this instrument when the voltage to ground is 600V or
higher even the line voltage is 600V or less.
Ensure that a measurement is performed at the secondary side of the circuit
breaker when testing the voltages of power lines, which has a large current
capacity, in order to avoid possible hazard to the user.
Extra precaution shall be taken to minimize the possibility of shorting the
power line with the metal tip of test lead at voltage measurement. It may
cause personal injury.
Do not start a measurement with the battery cover removed.
Connect the Earth cord (black) to the Earth terminal of the circuit under test.
Keep your fingers and hands behind the protective fingerguard during
measurement.

Set the Rage switch to any position other than OFF position.
Press the MODE button( ) and select VOLT mode.
No need to press the Test button.
KEW3127 has an AC/DC auto-detect circuit and can measure DC voltage as well.
At DC voltage measurement, when applying positive voltage to the Line Probe
(red), positive value is displayed on the LCD.

Ensure that the circuit breaker of the circuit under test is turned off.
(1) Connect the Earth Cord (black) to the earth side of the circuit under test and
the Line Probe (red) to the line side respectively.
(2) Confirm that the voltage displayed on the LCD is Lo . If the display doesn t
show Lo , voltage is applied on the circuit under test. Check the circuit under
test again and turn off the circuit breaker.

－ 14 －
6-2 Insulation resistance measurement

# DANGER
Confirm that no electrical charge exists on the circuit under test before
measuring by using a high voltage detector.
Put on a pair of insulated gloves for high voltage.
In case the Range switch is set to Insulation resistance range, high voltage
is being applied to the tips of test leads and to thecircuit under test
continuously while the Test button is kept pressed down. Be extremely
careful not to get electric shock.
Do not start measurement with the battery cover removed.
Never start measurement when thunder rumbling.
Connect the Earth Cord (black) to the earth terminal of the circuit under test.
When any mode other than VOLT mode is selected, live circuit warning
symbol appears on the LCD and the audible warning activates when a
voltage of 30V or higher is measured.
KEW3127 doesnt start a test, even the Test button is pressed down, if the
measuring voltage is 160V or higher: it starts a test if the measuring voltage
is under 160V upon a press of the Test button.
Prior to testing, ensure that the equipment under test is disconnected from
the mains supply and not energized in order to avoid possible electrical
hazards. This instrument may start a measurement for energized electrical
circuits. Be extremely careful not to get electrical shock.
Keep your fingers and hands behind the protective fingerguard during
measurement.

－ 15 －
 To check the insulation of electric equipments or electric circuits, measure
their insulation resistances by using this instrument.Ensure to check the
appropriate voltages to be applied to the equipment under test before starting
a measurement.

Note)
KEW3127 may show unstable readings when the insulation resistance of the
equipment under test is not stable.
Beep sound may be heard during insulation resistance measurement. But it
is not malfunction.
It takes time to measure a capacitive load.

At insulation resistance measurement, positive (+) voltage is outputted from

the Earth terminal and negative (-) voltage is outputted from the Line terminal.
Connect the Earth cord to the Earth (ground) terminal.
It is recommended to connect the positive(+) pole to the earth side when
measuring insulation resistance against the ground or when a part of the
equipment under test is earthed.
With this connection, smaller measured value can be obtained comparing
with other way round.

(1) Check the appropriate voltages to be applied to the circuit under test, and set
the Range switch to any desired insulation resistance range.
(2) Press the MODE button ( ) and select any of the following modes.
Mode Details
IR PI/DAR Performs normal insulation resistance measurements (consistent
measurements)
(Auto-measurement and display of PI and DAR. )
SV Increases the set voltage by 20% every time when pre-set time
comes.
DD Calculates dielectric discharge based on the measured capacitance
of the measured object and residual current values after testing.
RAMP Increases the preset voltage gradually to detect insulation failures.

－ 16 －
(3) Connect the Earth cord (black) to the Earth terminal of the circuit under test.
(4) Put the tip of the Line probe (red) to the circuit under test.
Then press the Test button. The buzzer sounds intermittently during
measurement when a range other than 500V(250V) range is selected.
(5) The measured value will be displayed on the LCD, and it remains displayed on
the LCD after a measurement.

CAUTION
Turn off the breaker of
the circuit under test.

(6) This instrument has Auto-discharge function. Keep the test leads connected
to the circuit under test and release the Test button when measurements end.
The auto-discharge function operates to discharge the electrical charges on
the circuit under test. Confirm that the voltage monitor shows 0V.

# DANGER
Do not touch the circuit under test immediately after testing.
Capacitance stored in the circuit may cause electric shock.
Leave test leads connected to the circuit and never touch the circuit until the
discharge completes.
Keep your fingers and hands behind the protective fingerguard during measurement.

Auto-discharge function
This is a function to discharge capacitance stored in the circuit under test
automatically after testing. Discharge condition can be checked on the voltage
monitor. This function will be canceled when removing the test leads 2 sec. or
more before discharge completes.

－ 17 －
(7) Set the Range switch to OFF position, and remove test leads from the
instrument.

Note)
The voltage warning mark stays on during a measurement and it blinks when
voltages of AC/DC 30V or higher exist on the circuit under test.
When measuring low resistances (if currents larger than the rated current are
output) over a long period of time, KEW3127 consumes large power and will
overheat. When this happens, further tests are automatically inhibited and the
over-temperature symbol appears on the display. The instrument must then
be left cool down. Testing shall be resumed when symbol disappears.
Short-circuit currents at a start of measurement may get lower when the
symbol appears.
Depending on the ambient temperature or measured resistances,
the symbol may appear and interrupt a PI measurement.

Principle of Insulation Resistance Measurement

Resistance value can be obtained by applying a certain high voltage to the
resistance (insulation resistance) and measuring the flowing current.

Resistance value = Voltage / Current

(RX = V / I)

－ 18 －
6-3 About BREAKDOWN mode and BURN mode
Either Breakdown mode or Burn mode can be set for each measurement: IRPI/ DAR,
SV, DD, RAMP.

(1) Breakdown mode

When applied voltage decreases drastically due to breakdown or current sudden
increase caused by insulation degradation, KEW3127 stops measurement
automatically so as not to develop further damage.
KEW3127 continues measurement until an event of breakdown or current
sudden increase is detected.

(2) Burn mode

When Buren mode is selected, KEW3127 continues measurement even if
breakdown or current sudden increase event occurs. Keep checking the
damage degree of the breakdown point and find the insulation failure point.
Testing performed in Burn mode is destructive.

When breakdown occurs

and measurement stops,
breakdown mark blinks.

When 250V Range has been selected, it is unable to select the Breakdown
mode.

－ 19 －
6-4 Continuous measurement
Press down and turn the Test button clockwise to lock it to perform a
continuous measurement of insulation resistance. After testing, turn the button
counterclockwise and set it to the initial position.

# DANGER
Be extremely careful not to get electric shock as high voltage is present on
the tip of test leads continuously.
Keep your fingers and hands behind the protective fingerguard during measurement.

－ 20 －
6-5 IRPI/DAR Measurement
At IRPI/DAR measurement, PI/ DAR values are automatically calculated and
displayed. During a measurement, values of current being measured and
capacitances measured at discharging after measurement are displayed.

IRPI/DAR Measurement Result

Output voltage

Resistance value
During measurement:
Time when Output current
a test ends End of measurement:
Capacitance
DAR or PI value

(1) Setting items

Setting items for IR PI/DAR are as follows.

Measurement duration:
Measurement automatically stops when the preset time period passes.
Output voltage :
For 2500V/ 5000V Range, voltage value is adjustable to – 20% of rated voltage,
can be set by 5%.
For 500V (250V) Range, either 500V or 250V is selectable.
Breakdown/ Burn :
Either Breakdown or Burn mode is selectable. (For 250V, Burn mode only)

－ 21 －
(2) Setting procedures
Follow the procedures below

[Stand-by state]
ENTER button( )
Setting of Measurement duration (with UP/DOWN button ( ))
ENTER button ( )
Setting of Output voltage*1 (with UP/DOWN button ( ))
ENTER button ( )
Setting of Breakdown/Burn (with UP/DOWN button ( ))
ENTER button ( )
Setting is finished.
(*1): 500V/2500V/5000V Range only

6-5-1 PI – Polarization index

This is to check a temporal increase of leakage currents flowing on insulations
and to confirm leakage currents arent increased as time passes.
PI is usually determined by the insulation resistances measured 1 min and 10
min after a measurement is started. PI is dependent on the shape of insulations
and influenced by moisture absorption, therefore, a check of PI is important to
diagnosis the insulation of cables.

Insulation resistance
(10 min after a start of test)
PI =
Insulation resistance
(1 min after a start of test)

PI 4 or more 4-2 2.0 - 1.0 1.0 or less

Criteria Best Good Warning Bad

－ 22 －
6-5-2DAR - Dielectric Absorption Ratio
DAR measurement is almost same to PI measurement in a sense that they test
the time course of insulation. The only difference is that DAR measurement can
get result faster than the other.
Insulation resistance
(1 min after a start of test)
DAR =
Insulation resistance
*1
(15 or 30 sec min after a start of test)

DAR 1.4 or more 1.25 - 1.0 1.0 or less

Criteria Best Good Bad

Note1: DAR time is selectable: 15 or 30 sec.

How to select:
Keep the MODE button( ) pressed down and rotate the Range switch to
power on KEW3127. (DAR mark starts blinking.)
Press the UP/DOWN button ( ) to switch 15 sec and 30 sec displayed at
the lower left on the LCD. Select the desirable one.
Press the ENTER button ( ) and confirm the selection.
Selected DAR time is saved and kept after the instrument is powered off. To
check the time currently selected, follow the step described as above.

6-5-3 How to measure DAR/ PI

DAR and PI are measured automatically at continuous measurement of IRPI/DAR
mode. Set the Range switch to any range and measure the test object continuously.

- 1 min after a start of continuous measurement:

LCD shows DAR value.
- 10 min after a start of continuous measurement:
LCD shows PI value.

－ 23 －
When DAR/PI values are displayed as--- :

DAR and PI values are determined by the methods 1. and 2. as described

above, therefore, they are displayed as --- when the measured insulation
resistances fall under any of following cases.
measured value is 0.0M
measured value is OL
* OL is displayed when the measured value exceeds the upper limit of the
measuring range at each insulation resistance range.

Range Upper limit

250V 12G
500V 120G
1000V 240G
2500V 1200G
5000V 12T

－ 24 －
6-5-4 How DAR/ PI values are displayed
LCD shows DAR/PI values as shown below during measurements.

(1) Start of test

No DAR/PI value,
“---” is displayed.

(2) 1 min after the start of test

DAR value is displayed.

(3) 10 min after the start of test

PI value is displayed.
Press the UP/DOWN button
( )to switch DAR and PI
values.

－ 25 －
6-5-5 How to review the measured DAR/PI values
Press the UP/DOWN button ( ) when measurements end. The measured
results are then displayed in following sequence. If the measurement ends earlier
than the intervals described in below (2), (3) or (4), blank displays arent shown
and returns to (1).

(1) Start of test

(A) Time when a test ends
(B)
(B) Value measured at the end of test
(resistance value)
(D) (C) DAR or PI value
(A)
(D) Capacitance
(C)
(2) 1 min after the start of test
(2) 1 min after the start of test
(A) Elapsed time (15 or 30 sec)
(B) Value measured 15 or 30 sec after a start
of test. (resistance value, output voltage)
(C) DAR value
(D) Output Current measured 15 or 30 sec
after a start of test.
(3) 10 min after the start of test
(A) Elapsed time (1 min)
(B) Value measured 1 min after a start of test.
(resistance value, output voltage)
(C) DAR value
(D) Output Current measured 1 min after a
start of test.

(4) Results at 10 min after a start of test

(A) Elapsed time (10 min)
Value measured 10 min after a start of
(B)
test. (resistance value, output voltage)
(C) PI value
Output Current measured 10 min after a
(D)
start of test.
Return to (1)

－ 26 －
6-6 SV Measurement (Step Voltage)
This is a test based on the principle that an ideal insulation will produce identical
readings at all voltages, while an insulation which is being over stressed, will show
lower insulation values at higher voltages. During the test, the applied voltage
incrementally steps by a certain voltage taking successive 5-time measurement.
Degradation of insulation may be doubt when insulation resistances become
lower at higher applied voltages.

SV Measurement Result
Output voltage

Resistance value

Time when During test: Output current

a test ends End of test: Capacitance

Present step

: 1st step
: 2nd step
･･･

: 5th step

(1) Setting items

Setting items for SV measurement are as follows.
(For SV measurement, 250V cannot be set at 500V (250V) Range.)

* Step time : Measurement duration per step.

* Breakdown/ Burn : Either Breakdown or Burn mode is selectable.

－ 27 －
Setting procedures
Follow the procedures below.

[Stand-by state]
ENTER button( )
Setting of Step time (with UP/DOWN button( ))
ENTER button( )
Setting of Breakdown/Burn (with UP/DOWN button( ))
ENTER button( )
Setting is finished.

6-7 DD Measurement (Dielectric Discharge)

This measurement method is usually used to diagnosis multi-layer insulations,
which requires the instrument to measure the discharge current and capacitance
of the measured object 1 min after the removal of the test voltage. This is a very
good diagnostic insulation test that allows deterioration and other problems voids
in the multiple insulations to be assessed.

Current value 1 min after completing

Dielectric measurement (mA)
Discharge
=
Voltage value when a measurement
Complete (V) x Capacitance (F)

DD 2.0 or less 2.0 - 4.0 4.0 - 7.0 7.0 or more

Criteria Good Warning Poor Very Poor

This criteria is a guide and could be slightly changed and be adapted to particular
objects under test based on practical experience of the users. This method has
been established to test high voltage generators installed in electric power plants
in the Europe countries.

－ 28 －
 DD Measurement Result
Output voltage

Resistance value

Time when Discharge current or

a test ends Capacitance (switchable with
UP/DOWN button )
DD or Voltage value
(switchable with UP/DOWN button )

(1) Setting items

Setting items for DD measurement are as follows.
(For DD measurement, 250V cannot be set at 500V (250V) Range.)

* Step time : Measurement duration per step.

* Breakdown/ Burn : Either Breakdown or Burn mode is selectable.

(2) Setting procedures

Follow the procedures below.

[Stand-by state]
ENTER button( )
Setting of Step time (with UP/DOWN button( ))
ENTER button( )
Setting of Breakdown/Burn (with UP/DOWN button( ))
ENTER button( )
Setting is finished.

－ 29 －
6-8 Ramp Measurement
Voltage used in Step voltage test is raised in steps but that used in Ramp
measurement is gradually raised. Therefore, Ramp measurement is useful to find
the points of insulation failure without causing serious damages. This enables
you to locate a fault, such as pinholes in windings, by seeing a spark or a wisp of
smoke.
KEW3127 displays the breakdown voltage value when insulation breakdown
occurs in load.

* Breakdown mode
When a breakdown occurs, KEW3127 stops measurement and displays the
voltage which caused breakdown. When no breakdown is detected, voltage is
raised till it reaches to the preset voltage value.

* Burn mode
KEW3127 continues measurement, even if a breakdown is detected, until applying
voltage reaches to the preset value. Breakdown voltage will be displayed after a
measurement.

Note: Ensure that the object under test is completely discharged before performing
a Ramp measurement.

Ramp measurement result

Output voltage

Resistance value

End of test:
Time when Output current
a test ends
Breakdown mark
Breakdown voltage (Either following marks
(Voltage value when breakdown blinks when breakdown
occurred.) occurs.)
: Burn mode is set
：Breakdown mode is set.

－ 30 －
(1) Setting items
Setting items for RAMP measurement are as follows.
(For RAMP measurement, 250V cannot be set at 500V (250V) Range.)

* Speed of voltage rise: Voltage rise per minute.

* Breakdown/ Burn : Either Breakdown or Burn mode is selectable.

(2) Setting procedures

Follow the procedures below.
Output voltage rate can be set between 100V/min and 9000V/min.

[Stand-by state]
ENTER button( )
Setting of Voltage rise speed (with UP/DOWN button( ))
ENTER button( )
Setting of Breakdown/Burn (with UP/DOWN button( ))
ENTER button( )
Setting is finished.

－ 31 －
6-9 Voltage characteristics of measuring terminal

KEW3127 Output characteristics (IRPI/DAR mode)

6000
5000V range
5000

4000
Output Voltage（V）

3000
2500V range
2000

1000 1000V range

500V range
0
250V range
0.1 1 10 100 1000 10 100 1000
MΩ MΩ MΩ MΩ MΩ GΩ GΩ GΩ
Insulation Resistance

* for 10sec after a start of test

6-10 Use of Guard terminal

When measuring the insulation resistance of a cable, leakage current flowing on
the surface of cable jacket and the current flowing inside the insulator are mixed
and may cause error in insulation resistance value. In order to prevent such error,
wind a conductive wire around the point where leakage current flows.
Then connect it to the Guard terminal as shown in the figure on the next page. This
is to move out the surface leakage resistance of the cable insulation to measure
only the volume resistance of insulator. Make sure to use the Guard cord supplied
with this instrument to connect the instrument to Guard terminal.

－ 32 －
 Ｌ Conductor

Power supply Leakage current Insulation

Protective wire
Ｇ
Indicator
Ｅ Cable with sheath

（Insulation resistance tester）

6-11 Filter function

KEW3127 has Filter function. Filter Mode is effective to reduce the variations in
readings due to external influences during high resistance measurements. The
filter type is Low pass filter with cut off frequency of 0.3Hz.

Press the FILTER button( ) to enable the Filter function. The Filter mark then
appears on the LCD. To check sudden variations in resistances, ensure that the
Filter mode is turned off.

6-12 Backlight function

This function to facilitate working at dimly illuminated location or at nighttime
work. The backlight doesn t work when the Range switch is set to OFF . It
automatically turns off 1 min after the last key operation; this feature is disabled
while a measurement is processed.

6-13 Auto-power-off function

The instrument automatically turns off approx. 10 min. after the last switch
operation. To restore from the auto power off status, set the Range switch to OFF
position once and then set it to any desirable range.

－ 33 －
7. Memory Function
7-1 Function Details
Measurement data of insulation resistance can be saved in the internal memory
of KEW3127.
Following data can be saved.
1. LOGGING: Measuring data is saved every second.
2. MEMORY: Data is saved at the end of measurement.

(1) Max number of file

1. LOGGING: Max 10 files
* Up to 100min in total
* Max recording time per file: 90min
2. MEMORY: Max 32 files

(2) Parameters to be saved

Following parameters will be saved. (common for LOGGING and MEMOR Y)
1. In all modes: Saved time & date, measured values (resistance, current,
voltage), capacitance
2. IR PI/DAR mode: PI/ DAR value
DD mode: DD value
Ramp mode: Breakdown voltage

－ 34 －
7-2 How to save data
Follow the procedures below to save the measured data.
Pressing the ESC button ( ), during operation, returns to the previous screen.

(1) Stand-by state

Data save in the MEMORY mode shall
be done after finishing a measurement.
(while the result is being displayed on
the LCD.)

(2) Press the MEMORY button.

(3) Select either MEMORY or LOGGING

with the UP/DOWN button ( ).

Blink
(4) Press the ENTER button.

When selecting When selecting LOGGING :

MEMORY :
(5) Saving completes and
back to stand-by state.

(5) Stand-by state

“LOGGING”
mark appears
(6) Press the TEST button.

(7) Measurement and logging start.

－ 35 －
7-3 How to recall saved data
Follow the procedures below to recall the saved data.
Pressing the ESC button ( ), during operation, returns to the previous screen.

(1) Stand-by state

(1s or longer)
(2) Press the MEMORY button for 1 sec or
longer.

(3) Select either MEMORY or LOGGING

with the UP/DOWN button ( ).
Blink

(4) Press the ENTER button.

Memory (5) Select a memory number with the UP/

No. DOWN button( ).

(6) Press the ENTER button.

(7) Saved data will be displayed. If the

recalled data is logging data, the latest
data will be displayed.

Press the UP/DOWN button ( )

to switch the display of current value
and capacitance value.

－ 36 －
7-4 How to delete data
Follow the procedures below to delete the saved data.
Pressing the ESC button ( ), during operation, returns to the previous screen.

Recall and display the data which one wishes to delete. (See clause 7-3 How to
recall the saved data.)

(1) Recall and display the saved data.

(1s or longer) (2) Press the ESC button for 1 sec or

longer.

(3) Confirmation screen is displayed.

(4) Press the ENTER button to delete the

data.

(5) Return to Memory No. selection screen.

－ 37 －
8Clock Setting
Follow the procedures below and adjust the internal clock of KEW3127. To confirm
the clock time, use the PC application KEW Windows or repeat the following
steps.

[Power-off state] (1) Hold down the ESC button and power
on the instrument.
+ Power on

1. Adjust year. (2) At the lower left on the LCD, Y

starts blinking. Adjust the year with the
UP/DOWN button ( ), and then
press the ENTER button ( ).
Blink

2. Adjust Month & day. (3) ThenM:Dstarts blinking. Adjust

the month with the UP/DOWN button
( ), and then press the ENTER
button ( ). Likewise, adjust day with
Blink
the UP/DOWN button ( ), and
Day then press the ENTER button ( ).
Month

3. Adjust Hour &Minute. (4) The last parameter,h:mstarts

blinking. Adjust hour with the UP/
Blink DOWN button ( ), and then
press the ENTER button ( ).
Minute Do the same to set minute and press
Hour the ENTER button ( ).

(5) Now clock setting completes.

4. Clock setting
Power off the instrument.
is finished.

－ 38 －
9. Communication Function/ Software
9-1 KEW3127 Settings
The PC software application enables analysis of the saved data from PC.
KEW3127 has following two kinds of communication methods.
(1)Bluetooth
(2)MODEL8212USB

Following can be done via PC communication.

(use software KEW Windows for KEW3127.)
* Downloading a file in the internal memory of the instrument to a PC
* Making settings for the instrument via PC.
* Displaying the measured results as a graph and saving them in realtime.

Communications with a PC cannot be established while operating KEW3127.

(e.g.: while setting measurement time, output voltage or saving data.)
When the instrument is out of the range of Bluetooth or MODEL8212 USB is
disconnected and the data download is failed, power off the instrument and on
again and retry the download.

－ 39 －
Instrument setting
Follow the procedure below and select the communication method on KEW3127
before starting PC communication.

1. [Power-off] state (1) Hold down the ENTER button and power
on the instrument.
+ Power on (2) LCD shows BT on. Use the UP/DOWN
button ( ) and select a desirable
2. [Setting] communication method and press the
ENTER button ( ).

* Selecting Bluetooth: set to “bt on”

3. Setting is finished. * Selecting MODEL8212USB: set to “bt off”

・When KEW3127 communicates via Bluetooth, Bluetooth mark is

displayed on the LCD. When KEW3127 communicates via MODEL8212USB,
USB mark is displayed on the LCD.

Using optional MODEL 8212 USB

(1) Connect MODEL 8212 USB to the USB port on a PC. (Refer to the instruction
manual for MODEL 8212 USB and install the special driver.)
(2) Connect MODEL 8212 USB and KEW3127 as illustrated below. Further
instructions for use are in the HELP for KEW Windows for 3127 .

－ 40 －
 Connect MODEL 8212 USB here. After connecting MODEL 8212
USB. (side view)

Interface
(1) Bluetooth
Bluetooth Ver.5.0
Compliant profile: GATT
(2 )MODEL8212USB
Communication method: USB Ver1.1
Software
KEW Windows for KEW3127 (Download this software from our homepage.
Refer to 9-2 How to install the Software .)
System Requirements
* OS (Operation System)
Please refer to version label on CD case about Windows os.CPU: Pentium
4 1.6GHz or more
* Display
1024 × 768 dots, 65536 colors or more
* HDD (Hard-disk space required)
1Gbyte or more (including Framework)
* .NET Framework (4.6.1 or later)
Trademarks
* Windows® is a registered trademark of Microsoft in the United States.
* Pentium is a registered trademark of Intel in the United States.
* Bluetooth is a registered trademark of Bluetooth SIG.

－ 41 －
9-2 How to install the Software
Followings are the instructions to install the software KEW Windows and
KEW Windows for KEW3127 .
(1) Before installing the software, followings shall be checked.
To prepare your system to install this software, please close all open
programs.
Be sure NOT to connect the instrument with USB until install is completed.
Installation shall be done with administrative right.
(2) Download the file "KewWin3127Inst_eng.exe" from our homepage. (http://
www.kew-ltd.co.jp)
(3) Run the "KewWin3127Inst_eng.exe".

Then following window appears. Click Next

Read through and understand the License Agreement, and check I accept…. .
Then clickNext .

－ 42 －
Enter the user information and specify the location to where install the software.
Then clickNext .

Confirm the information on install, and click Install to start installing.

－ 43 －
Click Finish when install completes.

An installation of KEW Windows for KEW3127 is followed by the installation

ofKEW Windows .

－ 44 －
To install the KEW Windows for KEW3127", you can follow the same
installation procedure described forKEW Windows .
If you need to remove this software, use theAdd/Remove Programs tool in
the Control Panel.

9-3How to start KEW Windows for KEW3127

Start and Quit
Start the software by; 1) clicking the icon for [KEW Windows] on the desktop,or
2) clicking [Start] [Program] [KEW] [KEW Windows]. Then the KEW
products, which have been installed in the KEW Windows, are listed up.
Select the KEW3127 on the list, and then click Next. Then a main
menu for KEW Windows for KEW3127 appears. Click [Data Download] or
[Instrument Setting].

－ 45 －
－ 46 －
9-4 Features of KEW Smart
Remote checking of measurements is possible without accessing KEW3127
using the special Android application KEW Smart .
The application KEW Smart is available on download site for free. (An
Internet access is required.)
Please note that communication charge is incurred separately for downloading
applications and using special features of them. For your information, KEW
Smart is provided on-line only.

Main features:
Checking of measurement
Measurements can be displayed in graphic or numeric forms on
Android devices in real-time.
Checking of KEW3127 setting
Settings of KEW3127 can be checked.
Saving measured results
Results can be converted and saved in PDF.
Transmitting measurement data
Saved data can be transmitted to a PC. Details can be found in the HELP for
KEW Smart .

Cautions:
Battery level of KEW3127 is not shown on Android devices. Ensure that the
battery level of KEW3127 is sufficient before starting to perform measurements
using these features. Charge battery if necessary.
Remote control, such as switching ranges of KEW3127, from Android devices
is not possible.

－ 47 －
10Battery Charging and Replacement
10-1 How to charge battery

# DANGER
Use only the Power adapter supplied with this instrument.
Connect the Power adapter to a mains socket outlet. The mains supply voltage
must not exceed AC240V.
Handling and storage instructions specified by the battery manufacturer should
be observed.

# WARNING
Never attempt to make any measurement if any abnormal conditions, such
as a break on the Power adapter or exposed metal parts are present on the
instrument. When unplugging the Power adapter from the mains socket outlet,
do so by removing the plug first and not by pulling the cord.

(1) Set the Range Switch to the OFF position.

(2) Confirm a battery is installed in the instrument.
(3) Slide the shutter of the terminal to the measurement terminal side and connect
the Power Adapter.
(4) LED Status Indicator flashes in red and the Battery Mark also flashes on the
LCD.
(5) The indicator lights up in green and the Battery Mark on the LCD stops flashing
and lights up. (Battery charge completes in about 8 hours.)

* KEW3127 cannot perform measurement while charging battery.

* Battery life and how many times can be
charged are depended on conditions of use
and environment.
* Storing rechargeable lead-acid batteries in a
low-charged state could lead to reduced life
and/or damage. When storing the battery for
a long period, check and charge the battery
at regular intervals.
-50-
50

－ 48 －
10-2 How to replace battery
# DANGER
Never open the battery compartment cover while making measurement.
To avoid possible electric shock, disconnect the test lead and Power Adapter
from the instrument before replacing battery. After replacing batteries, make
sure to tighten up the screw for battery compartment cover.

# WARNING
Always use 12V5Ah Lead acid battery PXL12050 or equivalent.

# CAUTION
Install battery with correct polarity.
Followings may cause battery liquid leak, heating, explosion or damage to
Case resulting injury.
* short-circuiting the positive and negative terminals,
* putting close to fire, or
* disassembly or modification.

(1) Set the Range switch to OFF position, and remove the test leads and
power adapter from the instrument.
(2) Unscrew and slide to remove the battery compartment cover on the side face
of the instrument. (Match the arrow mark on the battery compartment cover
with the engraved OPEN on the instrument case.)
Attention should be paid not to lose screws.

－ 49 －
(3) Pull up the battery as below and disconnect the red and black cables. (Pull the
positive and negative connectors upwards and disconnect them from the battery.)

Pull the connector upwards.

(4) Replace the old battery with the new one (lead-storage battery PXL-12050:
12V5Ah). Ensure that the connectors are properly attached and the metal
terminals of battery are not deformed, and then install the battery observing
the correct polarities.

(5) Slide and attach the battery compartment cover and tighten it with screw.
Ensure that the arrow mark on the battery compartment cover matches with
theCLOSEmark on the instrument case.

－ 50 －
11.Accessories
11-1 Metal parts for Line Probe, and replacement

# DANGER
In the electrical environment of CAT.II or higher, MODEL8255 should be attached
and used with the test lead. With the large exposed metal parts of MODEL8254
and 8019, the equipment under test may be shorted. It may result in failure of
the equipment under test and cause fire or lead to fatal or serious injury.

(1) Tip metal parts

MODEL8255: Standard Prod (straight type, with molded parts)
MODEL8254: Straight Type Prod
MODEL8019: Pickel Type Prod
To be used to hook the instrument.

(2) How to replace it

Turn the Line probe counterclockwise to remove the attached tip metal. Put
the tip metal you want to use to the hexagon socket and turn it to clockwise
together with the tip of probe, and tight up screws.

MODEL8255

Male Screw

Hexagon Socket
MODEL8254
MODEL8019

－ 51 －
11-2 How to use the adaptor for recorder
MODEL8302 is the adaptor for recorder (option) for output current measurement.
Connect it as shown in the below figure.
Output is DC1mA when current of 1A is flowing.

To recorder

－ +
To shield
or Earth

* MODEL8302 can measure currents up to 2mA.

11-3 Line probe with alligator clip(optional accessory)

(1) MODEL7168A Line probe with alligator clip
LINE

(2) MODEL7253 Long Line probe with alligator clip (15m)

－ 52 －
12. Disposing the Product
Waste Electrical and Electronic Equipment (WEEE), Directive 2002/96/EC
This Product complies with the WEEE Directive (2002/96/EC) marking requirement.
The affixed product label (see below) indicates that you must not discard this
electrical/electronic product in domestic household waste.

Product Category
With reference to the equipment types in the WEEE directive Annex 1, this product
is classified as a Monitoring and Control instrumentation product.

Disposing lead-storage batteries

When you throw away the batteries, be sure to cover their positive and negative
terminals and always observe local laws and regulations.
Insufficient insulation of the terminals may cause explosion or fire because
electrical energies remain in lead-storage batteries after use.

－ 53 －
MEMO

－ 54 －
MEMO

－ 55 －
 DISTRIBUTOR

Kyoritsu reserves the rights to change specifications or designs described in this

manual without notice and without obligations.

10-21 92-2156B