Vacuum Filled High Voltage Relays

 High Voltage Relays

These relays are quite similar in function to that of low voltage relays.

But the major difference is the contacts which are designed to operate at high voltages. 

Therefore, a high insulation is provided between the contacts, between the contacts and the earth, and between the activator and contacts. 

This relay contacts are typically placed in a different medium enclosed by ceramic or glass to prevent arcing at the time of switching.

Generally, two kinds of mediums: vacuum and high-pressure gas are used in these relays as contacts medium.

Vacuum Filled High Voltage Relays

As the characteristics like high-voltage breakdown, fast-recovery rate and an absolutely non-reactive and inert environment, vacuum is the ideal dielectric that contains a very

few gas molecules. 

The dielectric strength of vacuum is 10000V per 0.1mm in vacuum and also due to no air, the contacts become oxidation free. 

These relays have stable and lowcontact resistance, so these are widely employed in Radio Frequency (RF) applications.

The above figure shows the components in a vacuum relay. 

This type of relay permits the use of low-mass actuators with the small movement, which is enough to operate it. 

When the load is switched, an arc is formed in between the contacts. 

Due to the presence of the vacuum, this arc no longer stays, but breakdowns within a moment.