Seam Finishing, Multiple Thread, Cutting Blade, Versatile Stitch Options Zhejiang Lejiang Machine Co., Ltd. , https://www.cnlejiang.com
working principle
The standard loop consists of a built-in high-voltage stability standard capacitor and a standard resistance network. The computer collects the current and the phase difference between the standard loop current and the test loop in real time, and calculates the capacitance (CX) and dielectric loss (tgδ) of the tested product. ).
The data acquisition circuit adopts high-voltage stability devices. The acquisition board and the acquisition computer are completely floated and shielded by the iron box. The instrument casing is grounded and shielded. In addition, the anti-interference technology such as light guide data, floating ground, large-area ground, single-point ground, and digital filtering is used. In addition, the computer processes the data of hundreds of power grid cycles, so that the measurement results are stable, accurate, and reliable.
As can be seen from Figure 3, the high voltage side of the instrument's high voltage device and the measurement circuit are floating. Users can flexibly use multiple grounding methods according to different measurement objects and measurement needs. If the "positive connection method" is used for measurement, the "E" point may be grounded. When the "reverse connection method" is used for measurement, the "UH" point may be grounded and the E point may be left floating.
In the figure, except the test product CX, the rest is the instrument. The inner part of the thin wire frame has a high voltage of 15KV for 5 minutes and a rated voltage of 10KV. The instrument is equipped with a standard capacitor CN with a nominal value of 50 PF, tg δ ≤ 0.0001, and a withstand voltage of 10 kV. High voltage transformer, rated output power 1.5KVA.
★ "E" point is connected to the shielding layer of the instrument in the instrument and the measuring cable. It is not the earth. It is also not connected to the shell of the instrument. ! !
Instructions
★★★ Safe Operation Precautions
1. The grounding terminal of the instrument must be reliably grounded during use.
2. Only when the instrument's power supply is turned off and the test voltage selector switch is set to the “off†position, the contact with the rear of the instrument and its measuring cable and the test item are considered safe.
3, the instrument during the test, the operation of the "test voltage" selection switch is strictly prohibited.
4, ★ positive connection method UH end for high voltage, anti-wiring method IX end for high voltage, use must be based on the actual situation, the high voltage cable and ground to maintain a sufficient distance, use our company to provide special insulation cable measurement Large-capacity test items can be used to mop.
5. Do not replace fuses that do not meet the panel's indication.
6. When using, use the cables provided by the manufacturer with the instrument as much as possible to ensure the measurement accuracy.
7, operating keyboard
Standby ------ no.
Quick measurement ------- quick measurement, no anti-jamming function.
Anti-interference ------ anti-jamming measurement.
Connected ------- is connected to measure.
Print ------- Print test data after the test results come out.
Reverse ------ reverse connection method measurement.
Start ------- start high pressure, start measuring.
External ------ external method measurements. Also used to select the capacity of an external standard capacitor.
Stop ------- can interrupt the measurement during the test.
Turn on the power, the instrument first self-test
(Display screen, optoelectronic communication, memory, operation keys, digital-to-analog conversion, grid frequency), after the self-test passes, enter the home directory. At this point, press the screen prompts to complete the test.
After entering the measurement state, the user can use the "Stop" button to exit the measurement state at any time.
There is no need for manual intervention to make positive or negative connection measurements. The connection of the test line is consistent with the instrument operation measurement method. If you use the connection method of the positive connection method, when you test, press the “reverse connection†button to measure and you can also get the result. This result is not true and reliable.
When measuring externally, it will show “Please close the external high voltage!†and stop for a while. Wait until the external high pressure is turned off manually. After the external high pressure is turned off (the external high pressure must be turned off), press “START†again to complete the test.
If the external high pressure is not turned off, the test result is not true.
External standard capacitor capacity selection:
In the “External Modeâ€, press the “External†button once, then the external standard capacitor capacity “XXXXpF†will change. There are eight kinds of capacity for selection (the last one is for factory debugging, but the user is invalid).
50pF, 100pF, 150pF, 200pF, 500pF, 1000pf, XXXpF, XXXpF.
Should choose the same capacity as the external standard capacitor. If special external capacitance is used, the manufacturer can input the capacitance into the instrument. If the external capacitor selected is not equal to the actual value, the measurement result will be affected.
Positive wiring method:
Before applying power, place the "test voltage" switch in the "off" position. Connect the UH terminal with a large wire clip for special cables (marked with UH) to the high voltage end of the test object, and use the core wire end of the other dedicated cable (red, marked with CX) for the IX terminal to be tested. The lower end of the product CX, its shielded wire end (black, with the E mark) is grounded. If the lower end of the sample has a shielded terminal, the terminal can be connected to “E†with a wire and grounded.
After the power is turned on, press the "Positive connection" key. Selected positive connection mode: Select the voltage with “test voltage†switch: Then press “start†key to start the test.
Anti-wiring
Before powering on, place the “test voltage†switch in the “off†position, ground the UH terminal, and connect the core wire of IX (marked with CX) to the high voltage side of the test sample CX.
After the power is turned on, press the “Reverse†key to select the anti-wiring mode: use the “Test Voltage†switch to select the voltage, then press the “Start†key to start the test.
Special attention: the shielding "E" and IX potential close to the high voltage side of the test object can be shielded or floating, absolutely can not be grounded! ! ! Otherwise, the output of the internal high voltage transformer of the instrument is short-circuited.
External high voltage method
CB is an external standard capacitor and CX is the test item.
When the test object requires the test voltage is greater than 10KV or the sample product capacity is greater than 60000pF, can be measured with an external high pressure, that is not using the instrument internal high voltage, and an external high-voltage device for measurement.
Note: When measuring with the external high voltage method, the "test voltage" switch is set to the "OFF" position! Adjust the external voltage, then start the test.
After power-on, connect "external" button, select the external mode and the external standard capacitor capacity, you must set the "test voltage" switch to the "off" position! Adjust the external voltage, then start the test.
The instrument is a Chinese liquid crystal display, with Chinese characters prompting various types of test information. When the test is completed, the “print†key can be pressed to print the test results.