Principle of frequency conversion anti-interference dielectric loss tester

Principle of frequency conversion anti-interference dielectric loss tester

working principle

Under the action of AC voltage, the dielectric consumes some electrical energy, which will be converted into thermal energy and result in losses. This type of energy loss is called dielectric loss. When an AC voltage is applied to a dielectric, there exists a phase angle difference between the voltage and current in the dielectric. The residual angle δ of PSI is called the dielectric loss angle, and the tangent tg δ of δ is called the dielectric loss angle tangent. The TG δ value is a parameter used to measure the dielectric loss. The instrument measurement circuit includes a standard circuit (Cn) and a test circuit (Cx), as shown in Figure 1. The standard circuit consists of a built-in high stability standard capacitor and a measurement circuit, while the test circuit consists of the test sample and the measurement circuit. The measurement line consists of a sampling resistor, a preamplifier, and an A/D converter. By measuring the standard circuit current and the amplitude and phase of the tested circuit current separately, the capacitance value and dielectric loss tangent value of the test sample can be obtained through vector operation using a digital real-time acquisition method by a microcontroller. The instrument has adopted anti-interference measures internally to ensure accurate measurement under external electric field interference.

Technical Specifications

1. High voltage output: 0.5-10kV,

Add 500V to each level, there are a total of twenty levels, capacity: 1500VA

2. Accuracy: tg δ: ± (reading * 1.5%+0.06%)

Cx: ± (reading * 1.5%+5PF)

3. Resolution: tg δ: 0.001% Cx: 0.001pF

4. Measurement range: 0.001%<tg δ<

Internal high voltage: 3pF~60000pF/10kV 60pF~1 µ F/0.5kV

External high voltage: 3pF~1.5 µ F/10kV, 60pF~30 µ F/0.5kV

Power supply: AC 220V ± 10% 50 ± 1Hz

Measurement method: a. Single frequency: 45Hz, 50Hz, 55Hz, 60Hz, 65Hz

b. Abnormal frequency: 45/55Hz, 55/65Hz, 47.5/52.5Hz automatic dual frequency conversion

7. Harmonic adaptation: ≤ 3%

8. Usage conditions: -15 ℃ -50 ℃ Relative humidity ＜ 80%

9. Dimensions: 460 (L) × 345 (W) × 345 (H)

10. Weight: 35 kg

Precautions

1. This instrument can only be used on equipment that is powered off; The grounding terminal should be reliably connected to the grounding grid; Try to use the instrument in a wide, safe, and reliable location;

2. The tested equipment should be switched from the operating state to the maintenance state by disconnecting the high-voltage lead and cleaning it. After the preliminary insulation test is good, the instrument can be used for testing to prevent poor insulation of the tested equipment and damage to the instrument during the pressurization process;

3. Determine which type of wiring to use based on the installation of the equipment, and select its wiring method from the corresponding menu options;

4. Select the correct test voltage level based on different devices and choose the required voltage from the corresponding menu options;

5. In case of special situations that endanger safety during the testing process, the main power supply can be urgently turned off;

6. Disconnect the power switch on the panel and clearly disconnect the 220V test power supply before making wiring changes or completing the work; When retesting the same experimental equipment repeatedly, you can press the reset button to re measure, or you can choose to repeat after the previous test is completed;

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 tested equipment is well insulated and measured in an environment with low relative humidity;

When conducting experiments on large capacitance test samples, the grounding of the instrument and the grounding of the test sample should not be at the same grounding point to prevent the safety of the instrument from being affected by the rebound voltage or flowing waves during grounding discharge;

9. The instrument comes with a boost device, and attention should be paid to the insulation distance of the high-voltage leads and personnel safety;

10. The instrument should be reliably grounded, as poor grounding may cause machine protection or pose a danger.

11. 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;

12. Although the high-voltage wires (HVx) equipped with the instrument have been tested and qualified at the factory, they still need to be kept away from the human body and low-voltage test lines (Cx) during measurement; Both high-voltage core wires and high-voltage shielding wires are not allowed to be grounded and tested on the low potential parts of the circuit.

The core wire and shielded wire of CX input line are not allowed to touch the high-voltage part of the test circuit.

13. The instrument should be moisture-proof and prevent severe vibration;

When there is significant on-site interference and a single frequency cannot obtain a definite result, cross frequency measurement should be used, while single frequency measurement should be used for other situations.

After issuing the measurement command, if the measurement result does not appear on the screen for a long time (1 minute), it may be caused by the sample capacitance being too large or freezing. After restarting, reduce the measurement voltage and retest.

16. Short circuit of the test sample will prevent measurement, and the instrument will automatically protect it.

When the paper outlet above the printer head extends a section, press the button once to stop the paper feeding. Printing paper is allowed to be pulled outward.

Principle of frequency conversion anti-interference dielectric loss tester