Why Does Switch Size Depend on Stored Energy & Inductance?

[cabellos]

Why is the size of a switch determined by the stored energy that is to be interupted and by the inductance of the circuit it is connected to?

thanks,

Phil

 

[Suerbatica]

When you disconnect a switch in a circuit of a given potential, it has the ability to transmit current directly through the air towards the nearest part of the switch. Since the switch is a conductive disconnecting device, the two sides of the circuit are in very close proximity to each other initially at the first point of disconnection, (over time, they obviously become further spread apart), and it is very easy for electric current to "arc" to the other side of the switch. Arcing is bad.
In the case of inductance, if no diode is placed parallel with the coil, the collapsing magnetic field of the inductor causes a voltage spike in the circuit (Its direction dependant on the fields polarity). That spike means the voltage is now higher than the source voltage and it is much easier to arc again to the other side of the switch, and at farther distances.

Switch sizes are based on their interrupt capacity. What they can safely disconnect without arcing. There are many protection methods employed. Magnetics the polarize the air against conduction of electricity, air blasting to disorganize ionized air particles for the same reason (corona voltage), mylar barriers, etc etc.

I hope this helps :)

Suer

 

[ravenprp]

The size of a switch is determined by the stored energy and inductance because these factors are directly related to the amount of power that needs to be controlled and the potential risks involved.

Firstly, the stored energy in a circuit is the amount of energy that is stored in a component, such as a capacitor, inductor, or battery. This energy needs to be controlled and interrupted by a switch in order to prevent damage to the circuit or any connected devices. The larger the amount of stored energy, the larger the switch needs to be in order to handle and control it effectively.

Secondly, inductance is a property of a circuit that resists changes in current flow. When a switch is opened or closed, it can generate a high voltage spike due to the sudden change in current. This can cause damage to the switch and other components in the circuit. The size of the switch needs to be able to handle this potential surge in voltage without being damaged. The higher the inductance of the circuit, the larger the switch needs to be in order to handle the surge effectively.

In summary, the size of a switch is determined by the stored energy and inductance of the circuit it is connected to in order to effectively control and protect the circuit from potential damage. It is important to consider these factors in order to ensure the safe and efficient operation of the switch and the circuit as a whole.