CORONA-i XT-330 Corona Discharge Tester
・Corona Discharge Tester
・spark discharge Tester
Features of the XT-330
The XT-330 employs a newly developed capacitance tuning mechanism to allow it to support testing with changes in load capacity.
Furthermore, we have increased HV output power to about 400 W (which is double that of our previous model).
It is necessary to apply high frequencies and voltages to a test object to test for corona discharges. However, it is very difficult at 100 pF or higher because of the large current flowing for the capacitive load.
We have developed a load capability tuning mechanism for the XT-330 and it can now apply 10 kHz and 7 kV to 1500 pF.
As a result, the XT-330 is extremely useful not only for testing high-voltage capacitors, but also for all test objects with capacitance.
The tuning mechanism increases the types of parts that can be tested for corona discharges, which include capacitors (Max. 3000 pF, 10 kHz, 3 kV), coils, transformers, insulation films, magnetic wires, small motors, and high-voltage connectors.
The XT-330 tests for the presence of corona and spark discharges by generating selectable voltages (0 to 7 kVrms, No load) at selectable frequencies (10 k to 100 kHz) at the HV terminal.
The high voltage current (HV Curr.) flowing in the load is shown on the display of the XT-330 so you can see the impedance of the test object.
This is useful for estimating the state of deterioration during endurance testing.
The XT-330 generates stable clean sine waves (continuous) of high frequency and high voltage.
It uses this as a source for a stable corona discharge and tests items for durability at high frequencies and voltages.
The ability of the XT-330 to run continuously while monitoring for corona and spark discharges is a very important feature.
Conceivable Test Items
Power semiconductors, small motors, capacitors, coils, transformers, magnetic wires, connectors, insulating coating, and other items used under high voltage.
The Importance of Corona Discharge Testing
Corona discharges generate ozone, which is extremely corrosive and can break down insulating materials. This can eventually produce spark discharges and product breakdowns.
While spark discharges are easy to determine with parts such as coils and transformers because the parts stop working, there is a tendency to overlook corona discharges because parts basically operate as normal.
When there is a high electrical field in the vicinity of a high frequency electrode, gas is ionized. This starts a corona discharge, which grows from the continuous addition of sine waves. The corona discharge breaks down the insulating material, which eventually results in product failure. That is why it is crucial to screen out this problem before shipping.
Drive frequency 10kHz to 100kHz 1kHz step selectable
(The frequency range depends on the probe)
Drive voltage 1.0 to 40.0Vrms(manually variable)
HV output voltage 10.0kVrms 7.0kVrms 5.0kVrms 3.0kVrms(Probe selection)
Drive current 0 to 3.0Arms(Power Amp temperature 95 deg C or lower)
3.0 to 9.99Arms(For a short time, Power Amp temperature 95 deg C or lower)
Drive waveform Sine wave(Continuous)
Maximum continuous voltage output
Voltage output when load is connected, tuning to the position where the drive current is smallest, and the Power Amp temperature is 95 deg C or lower.
Specified load output frequency 10kHz to 20kHz(Probe Box PB37a,PB35a,PB33a)
30kHz to 60kHz(Probe Box PB37b,PB35b,PB33b)
50kHz to 100kHz(Probe Box PB37c,PB35c,PB33c)
Display High Voltage 0 to 7.50kVrms
HV Current 0 to 2000mA
Flashover 0 to 255 count
Corona 0 to 255 count
Drive Voltage 0 to 40.0Vrms
Power Amp temperature  20 to 130 deg C
Drive Current 0 to 9.99Arms
Wakeup Time 0 to 99.9s(0 means unlimited)
(Not displayed during measurement)
Real Time 0~99.9s(0 means unlimited)
Monitor Output High Voltage High-voltage waveform
Flashover Spark discharge waveform
Drive Voltage Drive Voltage Waveform
Corona Corona Discharge Waveform
Sync. out Synchronized signal
HV Current
Remote Connector
RS-232C Connector
Drive Mode Selector Auto / Manual
Measurement Types High Voltage, Flashover, Corona, Drive Voltage,
Drive Current, Wakeup Time, Real Time, HV Current
Dimensions 430 (W) x 470 (D) x 180 (H) mm (main housing)
430 (W) x 470 (D) x 180 (H) mm (Probe Box)
Mass 16kg (main unit)
13kg (Probe Box)
Electrical 800VA
requirements Operating ambient temperature 15 deg C to deg C
Operating humidity 30% to 80%(no condensation)
Storage temperature -20℃ to 60℃
Storage Humidity 10% to 80%(no condensation)
Rated power supply voltage AC100V, 220V (specified in advance)
Probe Box Specifications
Probe PB33a PB33b PB33c
Drive frequency 10kHz to 20kHz 30kHz to 60kHz 50kHz to 100kHz
Load tolerance 10kHz:1200pF to 3000pF
20kHz:300pF to 1500pF
30kHz:440pF to 1300pF
60kHz:110pF to 590pF
50kHz:270pF to 660pF
100kHz:70pF to 330pF
HV output voltage 3kVrms


Probe PB37a PB37b PB37c
Drive frequency 10kHz to 20kHz 30kHz to 60kHz 50kHz to 100kHz
Load tolerance 10kHz:660pF to 1500pF
20kHz:150pF to 750pF
30kHz:200pF to 600pF
60kHz:50pF to 270pF
50kHz:120pF to 300pF
100kHz:40pF to 150pF
HV output voltage 7kVrms


Probe PB35a PB35b PB35c
Drive frequency 10kHz to 20kHz 30kHz to 60kHz 50kHz to 100kHz
Load tolerance 10kHz:840pF to 2100pF
20kHz:210pF to 1050pF
30kHz:280pF to 840pF
60kHz:70pF to 370pF
50kHz:170pF to 420pF
100kHz:40pF to 210pF
HV output voltage 5kVrms
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