KYORITSU KEW 3121A User manual

KEW 3121A, 3122A, 3123A
KEW3121A, 3122A KEW3123A
INSTRUCTION MANUAL
HIGH VOLTAGE INSULATION TESTER

CONTENTS
Page
1．Safety warnings …………………………………………………1
2．Features …………………………………………………………2
3．Specifications ………………………………………………3〜4
4．Instrument Layout ………………………………………………5
5．Operating Instructions …………………………………………6
5-1．Mechanical Zero Adjustment ……………………………6
5-2．Battery Check ……………………………………………6
5-3．Insulation Resistance Measurement ……………………7
5-4．Continuous Measurement ………………………………7
5-5．Use of Guard Terminal ……………………………………8
6．Battery Replacement ……………………………………………9
7．Accessories and options ………………………………………9
7-1. Metal part for Line Probe, and replacement ……………9
7-2. How to use the adaptor for recorder …………………10
8．How to fix the Meter to the Hard case ………………………11
9．Cleaning Meter Cover …………………………………………12

−1 −
1. Safety warnings
Please read through these operating instructions before using the
instrument to avoid any dangers such as electrical shock and to
ensure safe operation of the instrument.
Pay particular attention to all WARNING and CAUTION in this
instruction manual. WARNING indicates warnings to avoid electrical
shock and CAUTION indicates cautions to avoid damage to the
instrument.
#WARNING
●This instrument cannot test live conductors. Ensure that the
circuit to be tested is powered off before performing a test.
●Never open the Battery cover or remove the Instrument panel
during a measurement.
●Confirm that the Rotary switch is at the OFF position, and then
connect the test leads.
●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 make any measurement if any abnormal
conditions, such as a broken cover or exposed metal parts are
present on the Instrument or test leads.
●Set the Function switch to OFF position after use, and ensure
the Test button is released and unlocked.
#CAUTION
●Do not expose the instrument to direct sunlight, high
temperatures, humidity or dew.
●Never leave the instrument in the environment of 60˚C or
higher temperatures.
●Do not use the instrument if it or test lead is wet.
●Remove the batteries if the instrument is to be stored and will
not be in use for a long period.
●Use a damp cloth with neutral detergent or water for cleaning
the instrument. Do not use abrasives or solvents.

−2 −
2. Features
● Battery powered, the instruments test insulation up to
100000MΩat 2500V for KEW 3121A, 200000MΩat 5000V
for KEW 3122A and 200GΩat 5000V and 400GΩat 10000V
for KEW 3123A.
● Suited for heavy duty electrical maintenance and servicing of
industrial installations, cables, transformers, generators and
switchgear where high voltage insulation tests are required.
● Dual scales for low and high ranges which change
automatically. Colour coded scales for easy reading plus
LED's that illuminate in matching colour.
● Drip proof construction. The case is sealed with rubber
gaskets to protect internal circuit against rain.
● Hard carrying case furnished as standard accessory. Houses
both instrument and test leads in compact form. Made of
plastic, it is highly water resistant.
● Designed for low power consumption. Since the maximum
current consumption is 90mA eight pieces of 1.5V SUM-3（or
equivalent ）permit about 6 hours of continuous operation
even when the instrument is used on maximum load or twice
longer on minimum load.
● Rated output voltage is maintained down to 100MΩfor KEW
3121A, 200MΩfor KEW 3122A and 0.2GΩ/0.4GΩfor KEW
3123A. This permits accurate measurements of low insulation
resistance.
● Optional adapter MODEL8324 is available for connection to
recorder and enables cable insulation monitoring.

−3 −
KEW 3121A KEW 3122A KEW 3123A
DC Test Voltage 2500V 5000 V 5000V 10000V
Measuring Ranges
0〜2000MΩ/
1000〜100000MΩ
（automatic change）
0〜5000 MΩ/
2000〜200000MΩ
(automatic change)
0〜5GΩ/2〜200GΩ
(automatic change)
0〜10GΩ/4〜400GΩ
(automatic change)
Accuracy Insulation
Resistance
±5% of reading
（100〜50000MΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±5% of reading
（200〜100000MΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±5% of reading
（0.2〜100GΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±5% of reading
（0.4〜200GΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±10% of reading
（100〜50000MΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
±10% of reading
（200〜100000MΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
±10% of reading
（0.2〜100GΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
±10% of reading
（0.4〜200GΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
Output
Voltage
2500V ±5%
（100〜50000MΩ）
5000V ±5%
（200〜100000MΩ）
5000V ±5%
（0.2~100GΩ）
10000V ±5%
（0.4~200GΩ）
Operating
Temperature & Humidity −10℃〜＋40℃at 85% max. relative humidity
Storage
Temperature & Humidity −20℃〜＋60℃at 90% max. relative humidity
Insulation Resistance 1000MΩmax./ 1000V between electrical circuit & housing case
Withstand Voltage 5000V AC for one minute between electrical circuit & housing case
Dimensions 200（L）×140（W）×80（D）mm
Weight Approx. 1kg（including batteries）
Power Source 8 pcs of R6P (AA) battery or equivalent
Accessories
Hard Carrying Case:M-9158 Test Leads
(Line Probe:M-7165A, Earth
Cord:M-7224A, Guard Cord:M-7225A)
Hard Carrying Case:M-9158 Batteries, Test Leads (Line
Probe:M-7165A, Earth Cord:M-7224A, Guard Cord:M-
7225A) Pickel type prod:M-8019
Optional accessories
Line cord with alligator clip：M-7168A
Optional adapter：M-8324
Pickel type prod:M-8019
Line cord with alligator clip：M-7168A
Optional adapter：M-8324
3. Specifications

−4 −
KEW 3121A KEW 3122A KEW 3123A
DC Test Voltage 2500V 5000 V 5000V 10000V
Measuring Ranges
0〜2000MΩ/
1000〜100000MΩ
（automatic change）
0〜5000 MΩ/
2000〜200000MΩ
(automatic change)
0〜5GΩ/2〜200GΩ
(automatic change)
0〜10GΩ/4〜400GΩ
(automatic change)
Accuracy Insulation
Resistance
±5% of reading
（100〜50000MΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±5% of reading
（200〜100000MΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±5% of reading
（0.2〜100GΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±5% of reading
（0.4〜200GΩ）
±10% of reading
or 0.5% of scale length
（ranges other than
listed above）
at 23℃±5℃
±10% of reading
（100〜50000MΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
±10% of reading
（200〜100000MΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
±10% of reading
（0.2〜100GΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
±10% of reading
（0.4〜200GΩ）
±20% of reading
or 1.0% of scale length
（ranges other than
listed above）
at −10℃〜＋40℃
Output
Voltage
2500V ±5%
（100〜50000MΩ）
5000V ±5%
（200〜100000MΩ）
5000V ±5%
（0.2~100GΩ）
10000V ±5%
（0.4~200GΩ）
Operating
Temperature & Humidity −10℃〜＋40℃at 85% max. relative humidity
Storage
Temperature & Humidity −20℃〜＋60℃at 90% max. relative humidity
Insulation Resistance 1000MΩmax./ 1000V between electrical circuit & housing case
Withstand Voltage 5000V AC for one minute between electrical circuit & housing case
Dimensions 200（L）×140（W）×80（D）mm
Weight Approx. 1kg（including batteries）
Power Source 8 pcs of R6P (AA) battery or equivalent
Accessories
Hard Carrying Case:M-9158 Test Leads
(Line Probe:M-7165A, Earth
Cord:M-7224A, Guard Cord:M-7225A)
Hard Carrying Case:M-9158 Batteries, Test Leads (Line
Probe:M-7165A, Earth Cord:M-7224A, Guard Cord:M-
7225A) Pickel type prod:M-8019
Optional accessories
Line cord with alligator clip：M-7168A
Optional adapter：M-8324
Pickel type prod:M-8019
Line cord with alligator clip：M-7168A
Optional adapter：M-8324

−5 −
④
⑤
③②①
④
⑦
⑥
⑧
⑪ ⑩ ⑨
4. Instrument Layout
①Line Terminal
②Guard Terminal
③Earth Terminal
④LED's for High & Low
Range Indication
⑤Press to Test Button
⑥Function Switch
⑦Meter Movement Zero
Adjust
⑧Battery Compartment
Cover
⑨Line Probe (Red)
⑩Earth Cord (Black)
⑪Guard Cord (Green) Fig.1

−6 −
CAUTION:
BE CAREFUL ABOUT HIGH VOLTAGE PRESENT ACROSS LINE
AND EARTH TERMINALS OF INSTRUMENT WHEN PRESS TO
TEST BUTTON IS OPERATED. MAKE SURE TO EARTH CIRCUIT
UNDER TEST. ALWAYS CONNECT EARTH TERMINAL OF
INSTRUMENT TO EARTH. THE BUZZER WILL KEEP SOUNDING
DURING INSULATION RESISTANCE MEASUREMENT.
5-1. Mechanical Zero Adjustment
With the function switch set at OFF position, adjust the meter
pointer to
∞ mark on the scale. Use a screwdriver to turn the
zero adjust screw located at the center of the front panel.
5-2. Battery Check
With the function switch set at BATT. CHECK position, operate the
press to test button. The batteries are good when the pointer stays
in BATT. GOOD area or to the right of this area. If not, replace them.
Note: Refrain from holding down or locking the press to
test button during this test as it will result in current
consumption larger than insulation resistance
measurement while the batteries are still new.
5. Operating Instructions

−7 −
5-3. Insulation Resistance Measurement
With the function switch set at OFF position, always connect the
circuit under test to earth. Attach the test lead to the earth terminal
of the instrument and connect to the earthed side of the circuit
under test. With the function switch set at 2500V and 5000V for
KEW 3121A and 3122A or 5000V or 10000V for KEW 3123A,
connect the black earth code to the earth terminal (EARTH) and
place the line probe in contact with the circuit under test and press
the Test button. When the green LED illuminates, read insulation
resistance on the outer scale (for high range). Use the inner scale
where the red LED illuminates. For insulation testing at 5000V
and 10000V, read the black and red scales respectively (for KEW
3123A). After a test, release the press to test button and wait for
several seconds without disconnecting the line probe from the
circuit tested. This is intended to discharge the charge stored in the
circuit tested.
5-4. Continuous Measurement
Make sure that the circuit under test is earthed and that the test
lead attached to the earth terminal of the instrument is connected
to the earthed side of the circuit under test. Push the press to test
button and turn clockwise to lock for continuous measurement.
When making this measurement, good care must be taken against
the high voltage continuously present across the line and earth
terminals of the instrument.
Note: Make certain that the circuit under test does not
include components which will be damaged by the
high voltage applied.