Matsayin Yadda a Kan Kula da AC Vacuum Contactors da Binciken Bayanarwa

A cikin aiki, AC vacuum contactors yana kasance da 'yan 'yanu daga abubuwan overvoltage kamar lightning overvoltage da switching overvoltage. Saboda haka, AC vacuum contactors ya kamata da kyau na voltage withstand capacity.

AC vacuum contactor ana sa shi ne a kan vacuum interrupter (na tattalin structure a Figure 1), housing, electromagnetic system, secondary circuit, da wasu muhimman components. Daga cikinsu, vacuum interrupter shine "heart" na AC vacuum contactor, kuma irin aiki masu shine take tabbatar da voltage withstand capacity na AC vacuum contactor.

1. Muhimmanci Factors da Hazards

Bayan a yi design da manufacture na vacuum interrupter, gap d bayan moving da static contacts ta zama bacewa. Saboda haka, yadda ake yi gap breakdown voltage yana da shakka da pressure p, wanda yana nufin vacuum degree na vacuum interrupter. Idan vacuum degree yana da shi, relative density na electrons yana da shi, kuma yanzu mafi yawan charged particles. Discharge capacity na gas yana da shi, saboda haka, breakdown voltage yana da shi, kuma voltage withstand capacity na vacuum interrupter yana da shi. Saboda haka, a cikin littafi, mafi vacuum degree, mafi yawan pressure, mafi dielectric strength na contact gap, mafi breakdown voltage, mafi voltage withstand capacity na vacuum interrupter, kuma a lokacin da shi, leakage current yana da shi.

Muhimmanci factors wadanda ke tabbatar da voltage withstand capacity na vacuum interrupter, ba a nan charged particles da ke cika a contact gap (vacuum degree yana da muhimmanci) ba, amma ke da outer shell na vacuum interrupter. Kamar yadda ake nuna a Figure 1, outer shell na vacuum interrupter an yi shi ne a kan ceramic ko glass. Saboda ceramic da glass suna da hydrophilic insulating materials, suka da kyau na ability to absorb water, kuma water absorbs impurities. A cikin applied voltage, wannan impurities ke ionize don charged particles da ke cause surface discharge, kuma ke reduce voltage withstand capacity na vacuum interrupter. A lokacin da shi, insulation strength na shell yana da shi, kuma leakage current yana da shi.

A cikin applied voltage, main contact gap na vacuum interrupter da outer shell na vacuum interrupter suka form parallel circuit. Idan surface discharge na vacuum interrupter yana canza zuwa flashover, yana nufin cewa vacuum interrupter yake break down along the surface na shell, wanda yake tabbatar da insulation performance na vacuum interrupter. Da amsa, don AC vacuum contactor, quality na outer shell yana da shakka da voltage withstand capacity.

2. Improvement Measures

Saboda voltage withstand capacity na AC vacuum contactor yana da shakka da vacuum interrupter, da muhimmanci factors wadanda ke tabbatar da voltage withstand capacity na vacuum interrupter suna da inside na interrupter da outer shell, measures yana da shakka da suka yi waɗannan labar.

Kima, tun daga perspective na inside na vacuum interrupter, ya kamata a duba abubuwan:

Improve physical structure na contacts don make electric field na vacuum interrupter as uniform as possible. Bayan a determine contact gap na vacuum interrupter, improving distribution na electric field a cikin interrupter don make it more uniform yana taimakawa improve voltage withstand capacity na vacuum interrupter da reduce leakage current.

A cikin practice, kafin, thickness na contacts ya kamata a increase, kuma sharp corners and edges na contacts ya kamata a blunt, don make electric field distribution a wadannan parts bacewa, wanda yana taimakawa improve voltage withstand capacity na vacuum interrupter. Amma, don high-voltage and large-capacity vacuum interrupters, ya kamata a design voltage-equalizing shield around the contacts, kuma auxiliary voltage-equalizing shield a end of the voltage-equalizing shield don effectively improve electric field distribution near the contacts. Designing end shields near the end caps at both ends na vacuum interrupter yana taimakawa effectively reduce electric field intensity near the end caps na vacuum interrupter.

Improve vacuum degree. Vacuum degree shine important parameter wanda ke reflect quality na vacuum interrupter. Vacuum degree na qualified vacuum interrupter yana da range, between 10^-4~ 10^-2 Pa, that is, 10^-6~10^-4 mmHg. Kamar yadda ake nuna a Figure 2, idan pressure na vacuum interrupter yana da shi da 10^-2 Pa, voltage withstand capacity ta zama da shi.

Contact surface ya kamata a smooth and flat. Idan an bukata, burrs na contact surface ya kamata a remove through conditioning.

Improve coaxiality. Guide sleeve yana iya effectively ensure coaxiality na vacuum interrupter, amma sometimes coaxiality ba a da shi a best state ba, kuma yana da shakka da suka adjust carefully. Improvement na coaxiality yana ensure effective contact na moving and static contacts, wanda yana taimakawa reduce contact resistance, reduce heat generated when the contacts are closed, and effectively reduce surface damage caused by fusion welding when the contacts are opened.

Tara, tun daga perspective na outer shell na vacuum interrupter, ya kamata a duba abubuwan:

• Increase creepage distance. Especially in the case of product miniaturization, this goal can be effectively achieved by designing the outer shell into a corrugated shape.

• Maintain cleanliness na outer shell and pay attention to use environment. Especially for vacuum switches used outdoors in polluted and humid environments, measures should be taken to keep the outer shell clean.

• For high-voltage and large-capacity vacuum interrupters, adding silicone grease insulation between the outer surface na vacuum interrupter and the insulating porcelain sleeve can effectively improve insulation strength na outer surface na vacuum interrupter. In addition, materials with high insulation strength must be selected to improve voltage withstand capacity na outer shell na AC vacuum contactor.

3. Conclusion

By improving internal insulation na vacuum interrupter and reducing surface conductivity na outer shell na vacuum interrupter, and improving voltage withstand capacity na outer shell na AC vacuum contactor, voltage withstand capacity na AC vacuum contactor can be greatly improved, and product quality can be enhanced.