Active Member
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[China]
Address: Layers Building 2,N0.2-2 Guannan Science&Technology Industrial Park, East Lake High-Tech Development Zone,Wuhan ,China
Contact name:Jianbin Cao
WUHAN FANKE HAIWO HIGH VOLTAGE TECHNOLOGY CO.,LTD. |
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VLF High Voltage Testing Machine , VLF AC Hipot Tester , Testing Large Capacitance object
I. Product Description Of VLF Test Technology :
Ultra low frequency insulation withstand voltage test is an
alternative method for power frequency withstand voltage test.
Using 0.1Hz ultra low frequency withstand voltage test replace
power-frequency withstand voltage test, not only is equivalent to
the same equipment, and greatly reduces the volume and the weight,
so the ultra-low frequency withstand voltage device is widely used
in large generators, cables, power capacitor test AC voltage
withstand test products.
II. Technogy feature advantage at DC test /power frequency test/VF test/ VLF test
| Aspects | DC | Power Frequency | Variable Frequency | 0.1Hz VLF |
| Equivalency | Poor | Good | Good | Good |
| Insulation Damage | strong | slight | slight | slight |
| Operation Safety | relatively low | relatively low | relatively low | high |
| Wiring Difficulty | complicated | complicated | most complicated | simple |
| Volume | smallest | largest | large | small |
See from the above table , VLF test is the substitute for power frequency test. It is suitable for testing electrical equipment with large capacitance.
III. Product advantage and Feaure
Data of current and voltage are obtained directly through the sampling of high-pressure side and it is true and accurate.
Over-voltage protection: the instrument will shut down to protection within 20 ms when the output voltage is exceeding limiting values of setting.
Over-current protection: design for dual protection of high and low voltage, downtime protection can be accurately set in high-pressure side. Shut down to protection times is within 20 ms when the current of low-voltage sides exceeds reacted current.
High-voltage output protection resistor design in the body boost and it is no need to additional outside resistor.
Closed-loop negative feedback control circuit of high and low voltage.
IV. General Technical data:
Remarks: Capacitance of test object can not be larger than the maximum value of the test instrument. If capacitance of test object is smaller than 0.05μF, the hipot should be equipped with an auxiliary device (supplied by HV HIPOT at your option).
V. Other typical model
| Model no | Rated Voltage/current | Load Carrying Capacity | Power FuseTube | Product Structure and Weight |
| VLF-30 | 30kV/20mA (Peak) | 0.1Hz,≤1.1µF | 5A | Controller:4KG Booster: 25KG |
| 0.05Hz,≤2.2µF | ||||
| 0.02Hz,≤5.5µF | ||||
| VLF-50 | 50kV/30mA (Peak) | 0.1Hz,≤1.1µF | 15A | Controller:4KG Booster: 50KG |
| 0.05Hz,≤2.2µF | ||||
| 0.02Hz,≤5.5µF | ||||
| VLF-90 | 90kV/30mA (Peak) | 0.1Hz,≤0.5µF | 20A | Controller:4KG Booster Grade 1(40kV):25KG Booster Grade 2(50kV):50KG |
| 0.05Hz,≤1µF | ||||
| 0.02Hz,≤2.5µF |
VI.Test Voltage standard by this test set
1 For MV and below class XLPE cable:
Test peak voltage formula: Ｕmax＝3Ｕ0,
Ｕ0＝Single-phase rated voltage of cable
Test time :60mints
2 For generator stator
Ｕtest＝1.414*βKＵ0,
Utest---- 0.1Hz peak test voltage (kV);
β-------0.1Hz and 50Hz voltage equivalent factor, usually taking 1.2;
K------ Usually take 1.3 to 1.5, generally take 1.5;
Uo----- Generator stator windings rated voltage (kV);:
