Vacuum Circuit Breakers and Vacuum Contactors

Vacuum circuit breakers and vacuum contactors are similar in concept to air circuit breakers and contactors, but their arc-extinguishing units are enclosed in a vacuum environment. This design improves environmental adaptability and provides superior insulation and arc-extinguishing performance, leading to widespread adoption.

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Vacuum Circuit Breaker

A vacuum circuit breaker (VCB) is a protective device designed to automatically or manually disconnect a circuit under fault conditions.

• Functions:

  • Automatically opens to protect the circuit during faults (e.g., short circuits, overloads).
  • Manually operated to interrupt load currents as needed.

• Features:

  • Provides robust protection for short circuits, overloads, and other circuit issues.
  • Used in high-voltage applications, particularly in circuits exceeding 110kV, often in combination with SF6 insulation.
  • Models include VS1-12, 12kV VS1, 24kV VJG-24, and ZW32.

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Vacuum Contactor

A vacuum contactor is designed for repeated operations and can interrupt load currents but does not provide short-circuit protection.

• Functions:

  • Withstands frequent mechanical operations due to its strong mechanical life.
  • Performs separation and holding actions upon receiving control signals.

• Features:

  • Equipped with normally open and normally closed contacts.
  • Lacks short-circuit current protection, distinguishing it from circuit breakers.

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Key Differences

Feature	Vacuum Circuit Breaker	Vacuum Contactor
Primary Function	Protection from overloads, short circuits, control and interlock actions.	Repeated switching of load currents.
Short-Circuit Protection	Yes	No
Applications	High-voltage systems (110kV and above).	Medium-voltage applications with frequent operations.

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Commonalities and Advantages of Vacuum Technology

Both devices employ vacuum as the medium for arc extinguishing, offering:

1. Enhanced Environmental Adaptability:
   Superior performance in challenging environments compared to air-insulated counterparts.

2. Improved Insulation and Arc-Extinguishing:
   Vacuum's excellent dielectric properties and efficient arc-extinguishing capabilities make it a preferred choice in many applications.

3. Specialized Applications:
   Vacuum circuit breakers are favored for their comprehensive protection, while vacuum contactors excel in scenarios requiring frequent mechanical operations without the need for short-circuit protection.