Heterodyne Dielectric Loss Tester
1. This instrument can only be used on equipment that has been de-energized; the grounding terminal must be reliably connected to the grounding grid,
It is recommended to use the instrument in a spacious, safe, and reliable location.
2. The equipment under test must be disconnected from the high-voltage leads and switched to maintenance state, cleaned, and after preliminary insulation tests are satisfactory, the instrument can be used for testing to prevent damage to the instrument due to poor insulation of the equipment under test during voltage application.
3. Determine the wiring method based on the installation situation of the equipment and select the corresponding wiring method in the menu options.
4. Correctly select the test voltage level according to different equipment and choose the required voltage in the corresponding menu options.
5. In case of special situations that endanger safety during testing, the main power can be urgently turned off.
6. Only after disconnecting the power switch on the panel and clearly disconnecting the 220V test power supply can wiring changes be made or work be concluded; when repeating tests on the same equipment, press reset and measure again, or choose to repeat after the previous test is completed.
7. To ensure measurement accuracy, especially when the loss of small capacitance test samples is small, it is necessary to ensure that the low-voltage end (or secondary end) of the equipment under test has good insulation and measure in an environment with relatively low humidity.
8. When testing large capacitance samples, the instrument's grounding and the test sample's grounding should not be at the same grounding point to prevent back-surge voltage or traveling waves from affecting the instrument's safety during grounding discharge.
9. The instrument comes with a voltage boosting device; attention should be paid to the insulation distance of the high-voltage leads and personnel safety; 10. The instrument must be reliably grounded; poor grounding may cause machine protection or danger.
10. After the instrument is started, except for special circumstances, it is not allowed to suddenly turn off the power to avoid overvoltage damage to the equipment;
11. The dedicated high-voltage wire (HVx) provided with the instrument has been tested and qualified at the factory, but it still needs to be kept away from the human body and the low-voltage test line (Cx) during measurement; neither the high-voltage core wire nor the high-voltage shielding wire is allowed to be grounded or connected to the low-potential part of the test circuit.
The core wire and shielding wire of the CX input line must not contact the high-voltage part of the test circuit.
12. The instrument should be protected from moisture and severe vibration.
13. When on-site interference is significant and power frequency measurement cannot yield definite results, heterodyne frequency measurement should be used; otherwise, power frequency measurement should be used.
14. If after issuing a measurement command, the measurement result does not appear on the screen for a long time (1 minute), it may be due to the test sample capacitance being too large or a system crash; restart the instrument and lower the measurement voltage before measuring again.
15. A short circuit in the test sample will prevent measurement, and the instrument will automatically protect itself. When a section extends from the paper outlet above the machine head, press the button to stop paper feeding. The printing paper is allowed to be pulled outward.
Instrument Structure
Measurement circuit: All calculations such as Fourier transform, complex number operations, range switching, and variable frequency power supply control.
Control panel: Printer, keyboard, display, and communication relay.
Variable frequency power supply: Uses SPWM switching circuit to produce high-power sine wave stabilized output.
Step-up transformer: Steps up the variable frequency power supply output to the measurement voltage, with maximum reactive power output of 2KVA/1 minute.
Standard capacitor: Internal Cn, measurement reference.
Cn current detection: Used to detect the current of the internal standard capacitor, 10μA～1A. Input resistance <2Ω.
Cx positive wiring current detection: Only used for positive wiring measurement, 10μA～1A. Input resistance <2Ω.
Cx reverse wiring current detection: Only used for reverse wiring measurement, 10μA～1A. Input resistance <2Ω.
Reverse wiring digital isolation communication: Uses precision MPPM digital modem to transmit the reverse wiring current signal.
