Difference between Vacuum Contactor Unit and Vacuum Circuit Breaker
Over the years, L&T Electrical & Automation (E&A) has earned a place amongst the leading low voltage switchgear manufacturers of the world. It has the scale, sophistication and range to meet global benchmarks. It has been offering Air Circuit Breakers (ACBs) for the last 45 years and has rich experience of developing electrical solutions
Difference between Vacuum Contactor Unit and Vacuum Circuit Breaker
A vacuum circuit breaker trips through an error like an earth fault, short circuit, over/under voltage. A contactor is usually performed in series through a fuse that provides to avoid fault current. The main difference between the vacuum contactor unit and the vacuum circuit breaker are listed below based on different characteristics.
| Vacuum Circuit Breaker | Vacuum Contactor Unit |
| Switching capacity is, it switches currents from low-values tocomplete system short-circuit current | Switch currents from very low values toDisrupting capacity of vacuum contactor without fuses. Fuses work for higher currents as compared with the interrupting ability of the vacuum contactor only, up to thedisrupting capability of the fuse |
| Endurance is high for mechanical | Endurance is extremely high for mechanical like 1,000,000 processes for up to 630A |
| Endurance is high for electrical is high like a vacuum that ranges from10k – 50k actions at rated continuous current. For vacuum, it is 30 to 100 operations at full short-circuit rating. | Extremely high switching continuous current ranges from 450,000 to 1,000,000 actions for up to 630 A. Switching short-circuit current, endurance data not established in short-circuitcurrent break that needs substitution of fuses |
| These are not applicable for extremely high endurance applications. | These are used for the operations of extremely frequent switching |
| It is operated electrically | It operates electrical only |
| It is mechanically latched because CB remains closed on system voltage loss. | Usually, the vacuum contactor unlocks oncesystem voltage is lost; vacuum contactor will lock once system voltage comes back |
| It uses protective relays | It uses protective relays for overload protection & fuses for the protection of short-circuit |
| Short circuit let through energy is low | Short circuit let through energy is low |
| Remote operation is suitable | Remote operation is suitable |
| Control power is used for the operation of CB, protective relays, & space heaters | Control power is used for the operation of contactor, protective relays & space heaters |
| It uses a larger area | It uses less area |
| Its cost is high | Its cost is moderate |
| Its maintenance is medium | Its maintenance is low. |
Advantages of VCB
Vacuum offers the utmost insulating strength. So it has extremely superior arc quenching properties than any other medium.
- The vacuum circuit breaker has a long life.
- Unlike Oil Circuit Breaker (OCB) or air blast Circuit Breaker (ABCB), the explosion of VCB is avoided. This enhances the safety of the operating personnel.
- No fire hazard
- The vacuum CB is fast in operation so ideal for fault clearing. VCB is suitable for repeated operation.
- Vacuum circuit breakers are almost maintenance-free.
- No exhaust of gas to the atmosphere and Noiseless operation.
Disadvantages of VCB
- The main disadvantage of VCB is that it is uneconomical at voltages exceeding 38 kV.
- The cost of the breaker becomes excessive at higher voltages. This is due to the fact that at high voltages (above 38 kV) more than two numbers of the circuit breaker are required to be connected in series.
- Moreover, VCBs production is uneconomical if produced in small quantities.
Applications of Vacuum Circuit Breaker
The vacuum circuit breaker is today recognized as the most reliable current interruption technology for medium voltage switchgear. It requires minimum maintenance compared to other circuit breaker technologies.
The technology is mainly suitable for mainly medium voltage applications. For higher voltage vacuum technology has been developed, but it is not commercially feasible. Vacuum circuit breakers are used in metal-clad Switchgear and also in porcelain housed circuit breakers.
Thus, this is all about Vacuum Circuit Breaker (VCB) working and applications. We hope that you have got a better understanding of this concept. Furthermore, any doubts regarding this concept or to implement any electrical and electronics projects ideas, please give your feedback by commenting in the comment section below. Here is a question for you, What is the working principle of VCB?