Corona Discharge Checker

Immediate detection of insulation deterioration under hot line condition!

Discharge detection based on frequency analysis!
MK-720 detects periodicity of corona discharge at AC power-supplied facilities
unaffected by ambient noises.
Ideal for insulation deterioration on insulators, disconnectors and circuit breakers.
Receiving ultrasonic wave from corona discharge enables us to survey electricalinstruments without contact.

MK-720L-E
Long-distance type
（Approx. 10m）

MK-720-E
Short-distance typeFeatures（Approx. 3m）

Detects insulation deterioration on insulators, disconnectors andRear sidecircuit breakers!
Precise measurement in 8 spot
Identiﬁes point of corona discharge with a laser pointerRecords measurement data（Component rate, Waveform, FFT data）
Easily transferable recorded data to PC via USB cable
Generates audible sound from corona discharge and transmit
Inlaid composite image for this photothrough an earphone

Corona Discharge Checker

Measuring principle

Broadband ultrasound is emitted with corona discharge due to insulation deterioration at AC powered facilities.
Since the intensity of the emitted ultrasound varies periodically with alternative voltage, double frequency components of power-supply appears prominently in frequency analysis after envelope detection of the received
ultrasonic wave.
MK-720 series can detect corona discharge without eﬀects of ambient noises by evaluating the intensity of
double frequency components of the power-supply.
Original wave

Through High Pass Filter

Envelope detection

FFT（frequency analysis）

060

120

180

240 [Hz]

Measurement display
Acoustic pressure level
while measuring

Rate of the intensity of
double frequency componentsof the power-supply to totalsound intensity（Discharge component rate）
Converted acoustic pressurelevel of double frequency
components of thepower-supply

Measured data is hold and memorised.

Detectedenvelopewaveform
FFTspectrum

Only MK-720L displays detected envelope waveformand FFT spectrum.

Speciﬁcations
MK-720L-E

Model

MK-720-E

Detecting frequency

Central frequency 40kHz

Detecting directionality±8°
Display of discharge component rate, Display converted value in accoustic pressure
Alarm based on discharge component rate, Measuring point indication with laser pointer（Laser pointer light intensity Class 2 IEC 6825-1）

Functions

Peak hold mode
Display of measured wave and FFT spectrum

Measurement sensitivity of Discharge component rate
（Discharge measurement:equivalent 100 to 300pC）*1

20 % and more at 2 meters distance,
6% and more at 8 meters distance

15 % and more at 1 meter distance

Discharge component rate, Converted value in accoustic pressureDatamemory Received ultrasound waveform , FFT, TOP10

Max. 200 values

Max. 500 values

Max. 70 values

Max. 10 values

OutputBuzzer by setting level excess
Signal output terminal（φ3.5mm mini jack）
USB port for memory data output（USB mini B socket）

Power supply

AA dry alkaline battery 4 pcs（over continuous 7 hours use)

Dimensions・Net weight

W 174 x H 272 x D 98mm Approx.370g（excluding batteries）

Measuring ambinent

0 - 40℃, 10 - 85%RH（non condensing）

Standard conﬁguration

Main unit, AA dry battery x 4, USB cable, Software（CD）*2, Earphone, Strap, Instruction manual, Inspection sheet

OptionSoft case（MK-9702）, Carrying case（MK-9703）, Reference oscillator（MP-161）＊1 Measurement sensitivityis based on the measuring reference oscillator（MP-161）, ambient temperature 25℃ degrees C indoor condition.
＊2 MK-720 series software requires English OS for Windows®, Windows Vista®, Windows® 7, WIndows ®8, 8.1 and Excel® 2003 or later.
※Windows®, Windows Vista®, Windows® 7, WIndows ®8, 8.1 and Excel® 2003 are registered trademark ofMicrosoft Corporation in the United States and other countries.

＊All speciﬁcations data contained in this catalog are subject to change without notice.

formerly Kawatetsu Advantech co.,Ltd.

URL ： http//www.jfe-advantech.co.jp/

Tokyo Head Ofﬁce（Overseas Sales）
JFE Kuramae Bldg., 2-17-4 Kuramae, Taito-ku, Tokyo
111-0051, Japane-mail：tokyo@jfe-advantech.co.jp Tel. +81-3-5825-5577 fax. +81-3-5825-5591
Head Ofﬁce and Main Plant
3-48, Takahata-cho, Nishinomiya-shi, Hyogo Pref,
663-8202, Japane-mail：honsha@jfe-advantech.co.jp Tel. +81-798-66-1508 fax. +81-798-65-7025© 2016 JFE Advantech Co.,Ltd.
EC-MK-720-E,720L-E-01A

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