Digital High Voltage Insulation Tester

KEW 3128

Microprocessor controlled high voltage insulation resistancetester with Diagnostic functions.

Graphic representation of the insulation resistance and leakage
current versus time on large display with bar graph and backlight.

Suitable for analyzing the insulation characteristics ofcables, transformers, motors, generators, high-pressure
switches, insulators, wiring installations, etc.

Can be operated from built-in rechargeable battery orfrom AC line.

6 ranges: 500V, 1000V, 2500V, 5000V, 10000V, 12000V
Fine adjustment of voltage setting at each range is also
possible.

Automatic discharge after test with monitoring of the discharge voltage.
Internal memory can store about 40,000 data (max).
Robust design for field use with IP64 rating (with lid closed).

KEW 3128 Functions
The KEW 3128 highest test voltage of 12kV offers greater flexibility for the testingof HV Machines than instruments with 5/10 kV test voltages that are normally available on the market.

The very high short-circuit current up to 5mA speeds up testing of capacitive
loads minimizing charging times.

Wide insulation resistance measurements up to 35TΩ

allows trends ofgood insulation to be monitored.
Six standard test voltages:
500V, 1000V, 2500V, 5000V, 10000V and 12000V. Fine adjustment of test voltage allows insulation testing according tomanufacturers’ specification.

Safety Design• Complies with IEC 61010-1 CAT.IV 600V, ideal protection level for industrial use.
• Live circuit warning by message on display and buzzer.
• Automatic discharge after test with monitoring of the discharge voltage.

Dual Power Supply
Rechargeable Battery and AC Power source. The built-in charger cancharge the battery and supply power to the KEW3128 simultaneously.

Dust and Drip Proof Design
Robust design complies with IEC 60529 (IP64), with lid closed

Large Graphical Display (5.7 Inch, 320 × 240 dots)
Graphic representation of the insulation resistance and leakage current versus time on large display
with bar graph and backlight.
Output Voltage

Bar graph

Measuring Time

Pre-set Voltage

No need for an extra recorder• Measurement up to 90 min is possible.
• Zoom in/out and scrolling of graphs is possible.

Leakage Current

Display of Measured Value

Memory Function• Internal memory can store up to 40,000 data in 32 files (max.)• Recording function up to 90 min with sampling interval of 1 sec.
• Print Screen function enables to record the display screens in BMP files.

Filters Function
This function is particularly useful for insulation resistance measurement that is unstable and difficult to read. In such cases, KEW3128 offers a selection from three kinds of filter.

Leakage current and Capacitance measurements
During the Insulation Resistance tests, the leakage current is also
displayed.
The capacitance of the object under test is also displayed after
Insulation Resistance tests.

Voltage and Frequency measurements
Voltage from 30 to 600V AC/DC and Frequency measurements from 45to 65Hz.

Graphic representation

Diagnostic Insulation Tests
In addition to the classical “spot“ Insulation Resistance tests, Leakage current and Capacitance measurements, KEW 3128 offers the following valuable Diagnostic Insulation tests.

PIPI Measurement (Polarization Index)

This diagnostic test recognises the fact that "good" insulation willshow a gradually increasing of Insulation Resistance after the test
voltage is applied. The Insulation Resistance is measured at twodifferent times: normally at 1 min and 10 min (other time settings arepossible). Then the instrument divides later reading by the earlier
reading, obtaining the result so called the Polarization Index (PI). PI isdependent on the shape of insulation, influenced by moisture and it
does not need to be temperature corrected.

Polarization
index

TIME 2Insulation resistance value 3 -10 min.
after starting measurement=TIME 1
Insulation resistance value 30 sec. - 1 min.
after starting measurement

DAR Measurement(Dielectric Absorption Ratio)

DAR

DAR measurement is a diagnostic test similar to the Polarization
Index (PI), but DAR takes the ratio of the Insulation Resistance usually
measured at 30 sec and 1 min (other time settings are possible)
instead of 1 min and 10 min typically of the PI.
DAR measurements are useful for instance when the PI is 2 or lesseven for new objects under test. In such cases, a min DAR value of
1.25 is required.

Dielectric=Absorption Ratio

TIME2
Insulation resistance value 30 sec. - 1 min.
after starting measurement
TIME1
Insulation resistance value 15 - 30 sec.
after starting measurementPI

4.0 or more

4.0 ~ 2.0

2.0 ~ 1.0

1.0 or less

DAR

1.4 or more

1.25~1.0

1.0 or less

Criteria

BestGood

Warning

Bad

Criteria

BestGoodBad

DD

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.
DielectricDischarge =Current value 1 min. after
completing measurement (mA)
Voltage value when a measurement
complete x Capacitance (F)SV Measurement (Step Voltage)* 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 some Europe countries.

DD

2.0 or less

2.0~4.0

4.0~7.0

7.0 or more

Criteria

GoodWarning

Poor

Very Poor

Data Communication Function
Dedicated application software KEW Windows and special USB adaptor
KEW 8212-USB are included as standard accessories. KEW Windowssoftware allows:• Downloading saved data to a PC
• Transferring and showing real-time data to a PC
• Analyzing of the saved data
• Setting-up KEW3128 via PC

SVThis is a test based on the principle that an ideal insulation will produce identical readings at all voltages, while an insulation which isbeing over stressed, will show lower insulation values at higher voltages. During the test, the applied voltage incrementally steps by acertain voltage taking successive 5-time measurement. Degradationof insulation may
be doubted wheninsulation resistances become
lower at higher
applied voltages.

●KEW 3128 Specification
Insulation resistance
Rated voltage
Max measurement value

500V
500GΩ
0~50GΩ
±5%rdg±3dgt*Accuracy is notguaranteed with setting of 250V or lessAccuracy

Short circuit current
Load resistor to output rated voltage
Output voltage
Rated voltage
Monitor accuracy
Output accuracy

10000V

12000V

0~100GΩ
±5%rdg±3dgt

0~250GΩ
±5%rdg±3dgt

0~500GΩ
±5%rdg±3dgt

0~1TΩ±5%rdg±3dgt

500G~5TΩ
±20%rdg

1T~10TΩ±20%rdg
10T~35TΩ
Values are displayed,
but accuracy isn’t guaranteed

35TΩ

250G~2.5TΩ
±20%rdg

0.5MΩ or more

1MΩ or more

Max 5.0mA
2.5MΩ or more
5MΩ or more

20MΩ or more

24MΩ or more

500V
±10%±20V
0~+20%
50~600V(in steps of 5V)

1000V±10%±20V
0~+10%
610~1200V(in steps of 10V)

2500V
±10%±20V
0~+10%
1225~3000V(in steps of 25V)

10000V±10%±20V-5~+5%
6100~10000V(in steps of 100V)

12000V±10%±20V-5~+5%
10100~12000V(in steps of 100V)

5000V±10%±20V
0~+10%
3050~6000V(in steps of 50V)

DCV : ±30~±600V, ACV : 30~600V(50/60Hz)±2%rdg±3dgt
5.0nA~2.40mA (Depending on the insulation resistance)
5.0nF~50.0μF

5.0nF~1.0μF (display range: 5.0nF~50.0μF)±5%rdg±5dgt

Withstand voltage
Operating temperature &humidity range
Storage temperature & humidity range
Applicable standards

Accessories

5000V
5TΩ

100G~1TΩ
±20%rdg

Selectable range

Dimension
Weight2500V
2.5TΩ

50G~500GΩ
±20%rdg*Accuracy is notguaranteed with setting of 250V or less

Voltage measurement
Measuring range
Accuracy
Current measurement
Measuring range
Capacitance measurement
Measuring range
Accuracy
GeneralPower source

1000V1TΩ

AC8770V : between line terminal and enclosure / 5sec (50/60Hz)
AC6880V : between the measuring terminal and enclosure / 5sec (50/60Hz)
AC2330V : between the power connector and enclosure / 5sec (50/60Hz)-10°C~50°C / Relative humidity 85% or less (when operating with an external power supply, no condensation)
0°C~40°C / Relative humidity 85% or less (when operating with battery, no condensation)-20°C~60°C / Relative humidity 75% or less (no condensation)
IEC 61010-1 CAT.4 600V Pollution degree 2, IEC 61010-031, IEC 61326, IEC 60529(IP64): with the lid closed.
Rechargeable Lead storage battery (12V)*Charging time: approx. 8 hours / AC Power supply (100V~240V, 50/60Hz)*Continuous measuring time: approx. 4 hours a load of 100MΩ at the Insulation resistance 12000V Range.
330(L) × 410(W) × 180(D)mm *Instrument and Hard case
9kg approx. (including battery) *Instrument and Hard case7226(Line probe), 7227(Line probe with alligator clip), 7224(Earth cord), 7225(Guard cord), 7170(Main cord), 8029(Extension prod)
8212-USB-W(USB adaptor with KEW Windows(Software)), Instruction manual, Calibration Certificate

EVERYTHING YOU NEED....
KEW3128 comes with everything you need for the Insulation Resistance measurements
and diagnostic tests of the object under test.
A full set of accessories is included : HV Line probe, HV Line probe with alligator clip,
Earth and Guard cords, extension prod and main cord.
PC software for downloading and interpreting of data and a dedicated interface cablewith USB are included. The instrument also comes in a robust hard case, a quick reference guide is attached to the case lid and it is supplied with a calibration certificate.

Please read the "Safety Warnings" in the instruction manual supplied with the instrument thoroughly and completely

correct use. Failure to follow the safety rules can cause fire, trouble, electrical shock, etc. Therefore, make sure
Safety Warnings : forto operate the instrument on a correct power supply and voltage rating marked on each instrument.

For inquires or orders :In consideration of the environment, soy ink and recycled paper were used in this publication.

The contents of this leaflet are subject to change without notice.

KEW3128-1E Jan. 09 AD