What Is a Vacuum Switch?
A vacuum switch is a device that activates or deactivates an electrical circuit by detecting pressure levels below atmospheric pressure. It operates based on vacuum pressure changes, controlling fluid flow or activating safety mechanisms when specific pressure thresholds are reached. Its unique feature of preventing arcing due to the absence of air makes it ideal for high-voltage electric power applications, where the switch mechanism operates within a vacuum to enhance safety and reliability.
Uses of Vacuum Switches
Vacuum switches have a broad range of applications, including:
1. For Automation Control
They are integral to the safety, protection, and control circuits of automated vacuum equipment. Uses span semiconductor manufacturing, chemical analysis, vacuum deposition, and pressure control systems, benefiting from the compatibility of silicon and stainless steel with various fluids.
2. For Electric Power
High-voltage circuit breakers utilize vacuum switches for reliable power transmission in buildings, factories, and railways. They ensure circuit interruption during malfunctions, with some designed as vacuum electromagnetic contactors for large motor control, primarily in 6kV and 3kV high-voltage circuits.
Principle of Vacuum Switches
Vacuum switches operate by sensing pressure changes and actuating a switch to open or close an electrical circuit. They consist of a sensor and a switch mechanism, which may be electric, pneumatic, mechanical, or electronic. The sensor detects vacuum pressure levels and triggers the switch based on preset limits, ensuring safe operation in various environments. For electric power applications, they interrupt current flow in case of system malfunctions, utilizing a vacuum valve construction to diffuse and quench arcs efficiently.
Features of Vacuum Switches
Key features include:
1. Wide Setting Range
They offer a broad vacuum pressure setting range, accommodating various operational needs.
2. Long Life
Designed for durability, vacuum switches boast a long lifecycle with minimal setting errors, often exceeding 1 million cycles.
3. Compatibility With Various Media
Constructed mainly from stainless steel, their welded seals are compatible with a wide array of gases.
4. Single-Pole, Two-Headed Contact
Many models feature a single-pole, dual-headed contact for precise ON/OFF control at set pressure limits.
Other Information on Vacuum Switches
Vacuum switches are also crucial in managing shock currents in electric power systems and high-temperature plasma experiments, effectively preventing overvoltages and ensuring circuit safety during large current accidents.