-. In graphic mode, two waveforms ( master sample and specimen under test)
are displayed on the screen whenever tested.
-. In text mode, text is only displayed, so it is possible to reduce testing
time during automatic test.

The following drawing shows the text mode as example.

⑧ Width selection digital switch ( 8 modes from 00 to 07 )
This switch is used to select one of 8 different kinds of waveform widths.
- The more increase the setting level, the more the scanned waveforms.
- The lower the setting level ( numeric figure), the smaller the scanned
waveforms ,which makes them accurately compared.


(Fig.1 ) Example of wider waveform in mode 07



As shown in Fig 1, by increasing the displayed range of waveforms, it increase
the displayed time range of waveforms. So these waveforms are displayed
for a long time and accordingly several waveforms are displayed on a screen.


(Fig.2) Example of reduced range of waveforms ( setting to 00 )

As shown in Fig.2, by reducing the displayed range(or time) of waveforms,
the front part of the scanning waveforms are only displayed so that only
1~2 waveforms can be displayed on a screen.

(N.B)
It is only effective to evaluate the waveforms scanned within the 80% of
rhe entire of screen which is started from the left on LCD screen.

(Fig.3) Example of recommendable display of waveforms

The 80% portion of the entire screen ( from the left of screen ) shall be
analyzed as the effective data for good/bad evaluation.
The recommendable number of waveforms is 3~4 (Fig.3), because
the measured data , due to whether narrow width of waveform( Fig. 1) or
wide width of that ( Fig. 3), is inaccurate for good/bad evaluation.

-. If the waveform is excessively wide as shown in Fig. 1 (setting to 07),
It makes not only an empty space in the left of waveform but also phase shift
due to bad influences, such as stray capacitance of product under test,
capacitance unbalance caused by being connected with additional equipments.


⑨ Start button
It is start button, the test result shall be displayed within the test duration
of 0.5 seconds.

⑩ Auto/Manual Mode Selection switch

This switch id used to select the auto/manual operation.
- In auto mode, the test results ( good/bad) are automatically determined.
- In manual mode, good/bad decision shall be made while seeing the screen.

The following conditions are only practiced in the manual mode;
- Setting of testing condition
- Collecting/ memorizing waveform of master sample.

⑪ Pulse Frequency Selection switch ( 01 to 20 )

This switch is used to preset the number of impulse applicable to the product
under test, which can be adjusted from 01 to 20 of impulse.

By the way, the waveform of master sample for good/bad evaluations is only
determined by the final impulse among the applied impulses.
Other impulses are used to check the previous quality before final evaluation.

⑫ Output Connector

It is outlet which generates a high voltage of impulse for testing.
The impulse voltage is applied to product through the two cables
connected to this output connector.

- Red cable ( " + " part ) ; high voltage flowing
- Earth cable ( " - " part ); for grounding


⑬ Connector to outside remote control start switch
This connector is used for the outside using of start button

1. Description of panel in front

① H/V OUTPUT Terminal ( " + " part ) : High surge voltage is flowing

② EXTERNAL I/O connector : 15 (No 1 ~15)? kinds of memory address can be assembled.

③ RS 232 SERIAL TERMINAL

④ Fuse : 2A rated fuse.

⑤ BUZZER ON/OFF switch

2 Reference waveform and its setting limit

2.1 How to use

The operation of this equipment is, first of all, to establish the standard value
throughout the optional address number.
The next procedure is to select the suitable setting limit(%), determined by user.
The detailed memorized data as test condition are the tested output voltage,
the number of pulse, width of waveform of master sample and the
percentage(%) of error limit for good/bad evaluation.
When the waveform of product under test exceeds the setting limit(%)
then, it is evaluated " Bad".
The product if it is within the setting limit is evaluated "Good".


2.2 Storage of master waveform

This equipment is designed for a memory type of sample waveform.
In order to compare/test the surge waveform of any product
the waveform of master sample, as specific requirements, should be
stored into an optional number of its memory.



① Connect two output connecter⑫ of high voltage cables
( red for +, black for -) into two wires ( one for start, other for finish)
of master sample

② Turn on Power supply ① .

③ Put Auto/Manual mode selection switch ⑩ into manual mode.

④ Set test voltage 0.5-3 kv (5kv) by using test voltage digital switch

⑤ Set Width Selection Digital switch to a certain number (00 to 07 ).
- If put to 00 setting, the displayed range of waveforms becomes small
as shown in Fig.2 so that one or two waveforms are displayed on the screen.
- If put to 07 setting, many waveforms are displayed like Fig. 1, then it is also
difficult to analyze it.

So, 03 setting is recommended. But, the other setting may be also available,
if required for good evaluation.

⑥ Adjust Pulse Frequency Selection switch ⑪ to the desired position ranging
from 01 to 20. The setting of this mode shall be selected in order to
apply the suitable number of impulse to the product under test.
- When setting to 01, one pulse shall be applied to the product under test.
- When setting to 20, 20 pulses shall be applied to the product under test.

However, an extraction among the several waveforms for evaluation is only
determined with the waveform resulting from final pulse among pulses.
By increasing the set mode number, more impulses are applied to the product
electrically, and the more accurate test can be performed although test
duration time is spent a little longer due to its test interval.

⑦ Select the optional memory number with Model selection switch③,
The memory address are ranged from 00 to 60, and the maximum
memory capacity for waveform storage is also 60.

The stored number for memory data can be randomly selected by optional
number. The number of memory is important as it is used to recall its stored
waveform as master waveform.
For this reason, this number should be recorded for next use.

⑧ Press Program storage button ⑤, Then all the preset test data ( master
waveform and its text) are displayed on the screen and stored to the
indicated memory address within 2.5 seconds.
After that, it is always possible to recall the memory address ,memory number,
by Program storage button ( while program button is " on" )

● How to recall this data as specific value.

⒜ Push Model selection switch and select memory address number.
⒝ Set Start switch in auto mode.
⒞ Push Start switch in auto mode, and the same output voltage shall
be applied to product equal to master sample.

Then, both data of master sample and of product shall be displayed on screen
on the same time, these results shall be stored by Program storage button.

For another product, the measurements are performed like mentioned above.
but, it is required for another memory number in the same way.

3 Test operation of D. Surge Tester

3.1 Comparison test procedure

The master waveform relating to each model should be stored at the indicated
memory address according to above mentioned procedure. Then, it is
necessary to recall /compare the stored waveforms with that of product.
This comparison and/or judgment is regarded as one of the test processes.

● How to proceed comparison test process.

⒜ Connect Auto/Manual selection switch ⑩ to Auto mode.
⒝ The address number, stored with master waveform, shall be
selected by using Memory selection switch ③
⒞ Connect product under to output connector ⑫.
⒟ Press Start button ⑨

Above table shows all for test procedure.
It is started automatically as soon as pushing start button.
and is completed within 0.5 second.
All of data are completely compared /analyzed, and the evaluated
results are displayed on screen.

To continue test, it is just to connect another test item to the output
connector (⑫ of front panel ) and push it again.
During test, high-voltage impulse 0.5-3kv (5kv) preset by
test voltage setting switch⑥ is applied to cable of output connect.

More attention is required during test, because the impulse
voltage ( red clip) can cause a high electric shock injury
although it is small current of 0.5-50 ㎲.

3.2 Selection of surge test voltage

The following is calculation formula of test voltage applicable to
surge tester, and this formula is recommended by ICWA (International
Coiling Winding Association), and is derived from long experience
( i.e., Rule of Thumb ) , but not based on the logical principle.

Calculation formula of surge test voltage (by ICWA)
Es= ( 2Eo + 1000 ) x 1.4
Es Surge test voltage
Eo Using voltage of product under test

It means that surge voltage is only related to the using voltage
of product under test, but not to size/output power of the products.

According to above formula, even small battery of 1.5 V is recommended
to test with surge test voltage not less than 1000 volts.
But, it is not reasonable in technology. So, it is assumed that above formula is
only applied to product of the using voltage not less than from 0.1 to 10 KV.

We, KAST Engineering, recommends the following formula as the reasonable
factor, which is based on our long manufacturing/ experimental experience.

Calculation formula by KAST's recommendation
Es= Eo x 60
Es Surge test voltage
Eo Using voltage of product (specimen)


The surge test voltage may be applied according to KAST's calculated
high voltage( 60 Eo), and this figure '60" is determined by the sum of
40 times of the using voltage of product and 20 times of the safety margin.
This recommendable figure is based on our experience that impulse
measurement of almost coiled product is not more than 40 times of its
using voltage of the product.


3.3 Evaluation of test result

This equipments displays the test result in the way of graphic mode
and its text ( setting to ⑦ )
In graphic mode, both waveforms ( sample vs product ) are displayed
on the screen whenever every test is completed (Fig.4 )

( Fig. 4 ) Displayed screen in graphic mode

Note)
The displayed figure of Error 1 shows the percentage of difference in the absolute
area of two waveforms ( master(referenc) vs specimen )

Error 1 = (A-B) / A × 100(%)

The evaluation is useful when there is in difference between the amplitude
of the sample waveform ( " a" curve in Fig. 4) and that of product's waveform
( "b" curve in Fig. 4), and when there is difference in attenuated curve
between sample(master) and product's waveform, induced by the difference of Q.

If the test result of product in graphic mode is evaluated to be good(OK)
which is within reference(specific) limit, the waveform and the mark " O.K "
is displayed without Error 1 and Error 2.

On the other hand, the meaning of Error 2 shows the percentage of the
difference area of two waveforms divided by sample waveform( if phase shift
of two waveforms are occurred although the equal amplitudes are measured)

In Fig.5, When the calculation is made, many factors, such as sample waveform(A),
test waveform(B), and their polar differences are also taken into considerations.
In addition, the other factors, such as difference in phase shift between two
waveform,wave distortion and deviated area due to noise including corona, are
also considered as the important sources for good/bad evaluation.

( Fig. 5); Calculation method of Error 2 (deviation including polarity of waveform)

Error2 = B/A × 100(%)

Let C = A- B ( Deviated area )

Throughout above calculation, the evaluation for the measured results
is more reliable in accuracy.
For example, test result might be evaluated to be "bad" due to the some
other influent factors, such as noise including corona and/or shaking of
waveform, if any, although the amplitude and phase shift of product
is measured as much as that of master sample as shown in Fig. 6.


( Fig. 6) Example for the evaluation of changeable waveform due to corona

If the tested coil has a weakness in insulation resistance, the corona or
spark occurs and is displayed as several kinds of pulse shape on the
measured waveform as shown in Fig.6.

Above drawing shows an example of corona occurred in case of
measurements with AD converter set to 20 MHZ.
This phenomena, occurrence of the deviated area, is more useful
for good/bad evaluation of product under test.

3.4 Use in text mode

1) How to use text mode

Tester shall be in text mode when The ⑦ switch of panel drawing is
selected to text mode.
Then, text shall be displayed on the screen and waveform shall be disappeared.


( Fig. 7) LCD screen in the Text mode

2) Recommendable text mode for mass tests.

As mentioned above, the test result shall be displayed into two mode,
One is " Graphic mode", the other is " Text mode".
When used in text mode, no any special time is taken to display the waveform
on the screen so that it can be more effectively used to perform the mass
tests on the automatic production line.
It takes about 0.5 seconds in the graphic mode and 0.2 seconds in text mode.
So, it is recommended to select the text mode for mass tests.

4 Composition & Circuit of digital surge tester

This test consists of circuit (Fig. 8) and hardwares(Fig.9), the block
diagram of this tester is explained as below;

① PCB ① ( down layer)
It is a SMPS circuit to rectify the AC 20V power to DC voltage, so as to
generate the power of approximately 600V , 40 kHz.

② PCB ② ( up layer )
AC 600V from PCB① is multiplied and rectified to generate DC 0.5-5 KV.

③ PCB③ ( up layer )
DC 5V power supply circuit is supply the power to LCD panel.

④ PCB④ (down layer)
This is a high voltage dividing circuit and high signal input/output circuit.


⑤ PCB⑤( up layer )
It is On/Off circuit of high voltage, which is equipped with SCR
for impulse generation and its trigger transformer.

⑥ A/D converter board⑥

⑦ PCB⑦
It is equipped with A/D converter and CPU circuit used to control the tester

⑧ T1 ( Transformer 1)
This transformer supplies power to LCD display panel and/or SMPS.

⑨ T2 ( Transformer 2)
This transformer supplies power to CPU, PUB and Trigger signal
generation circuit.

5 Using of comm.-porter ( RS-232C )

This tester is equipped with RS-232C, serial interface type, which can
be interfaced to a computer system.

For first use of tester with computer, " User program" should be downloaded
from our homepage ( www.kasteng.com ) and installed into the computer.
The file name of this program is KT-903D( V1.0)

Using computer system, the checking, testing and test results of Surge tester
can be perfectly performed.


* Regulation of Surge tester

Instruction ME + [CR]


③ Recalling of data file ( reference waveform )

Instruction WS + [CR]
Returned value 300 bites Hex data ( 1 file)

④ Recalling of data file ( measured waveform )

Instruction WT + [CR]
Returned value 300 bites Hex data ( 1 file)

⑤ Control instruction for test start

Instruction ST + [CR]
Return word None
Operation Same operation like start button is proceeded.


⑥ PIN composition of RS-232C

port pin No