The difference between vacuum circuit breaker and vacuum contactor

While both vacuum circuit breakers and vacuum contactors utilize vacuum as an interrupting medium, there are some key differences between the two. Here are the main distinctions:

1. Application: Vacuum circuit breakers are primarily used for circuit protection and interruption, whereas vacuum contactors are specifically designed for switching and controlling electrical motors and other heavy-load applications. Vacuum contactors are commonly employed in industrial settings to control motors, pumps, transformers, and other power-consuming devices.

2. Current Rating: Vacuum circuit breakers are designed to handle higher current ratings, typically ranging from several hundred amperes to several thousand amperes. On the other hand, vacuum contactors are typically used for lower current ratings, often up to a few hundred amperes. The current-carrying capacity of vacuum circuit breakers is typically higher than that of vacuum contactors.

3. Breaking Capacity: Vacuum circuit breakers are designed to interrupt fault currents and short circuits, necessitating a high breaking capacity. They are capable of breaking and extinguishing high-energy arcs. Vacuum contactors, on the other hand, are primarily used for making and breaking normal load currents and do not require as high of a breaking capacity as circuit breakers.

4. Arc Control: Vacuum circuit breakers are designed to effectively extinguish and control high-energy arcs that occur during fault conditions. They are equipped with arc chutes and other mechanisms to ensure reliable arc interruption. Vacuum contactors, on the other hand, are not typically designed to handle high-energy arcs and may not have advanced arc interruption capabilities.

5. Protection Functions: Vacuum circuit breakers are often equipped with protective features such as overload protection, short-circuit protection, and ground fault protection. These protective functions are not typically incorporated into vacuum contactors, as their primary purpose is switching and control rather than comprehensive circuit protection.

6. Design and Construction: Vacuum circuit breakers are typically built as standalone devices and are often enclosed in metal housings. They are designed to be integrated into power distribution systems. Vacuum contactors, on the other hand, are often constructed as modular units with replaceable contacts. They are typically mounted in motor control centers or switchgear panels.

It's important to note that while both vacuum circuit breakers and vacuum contactors use vacuum interrupters, they serve different purposes and have distinct design considerations based on their intended applications.