Good Old days?

A change in technology is an interesting phenomenon. It often meets with resistance initially, but in retrospect it is the exact opposite and one often wonders why it did not happen faster.

To visualize this we have a nerdy BL!XT story for you.

The discussion takes place in a not too distant future, when electronics have totally replaced mechanics in the field of electricity:

– Is this such a mechanical switch as you had in the past?
– Yes, it’s an mechanical circuit breaker. It was the most proven and safest one around.
– How did it work?
– It needed a proper over current to trip.
– So there was no limit to how much current could go through the wire?
– Well, the more power, the faster it tripped.
– So you mean that you could charge the power grid with 10000A?
– Yes, the current spikes could be that high.
– For how long?
– The mechanical arm needed to change position to OFF. For the smallest fuses it took about 3ms and the large 300ms.
– Are you kidding? There is no electricity network that can handle these spikes, is there?
– Well, the network had to be oversized quite heavily.
– Yes, but 10,000A?
– No, you’re right. Quite often the spike traveled and damaged the grid further up the chain.
– Then whole districts must be without electricity.
– Yes, unfortunately it happened sometimes.
– What happened when you broke the big current?
– Then an arc was formed.
– Could that not weld the mechanical arm in a fixed position?
– Yes. Therefore, continuous manufacturing tests were performed with 500A.
– But 10000 A is enough to start a fire if it is allowed to float for 300ms. R = (220V / 10000A) = 22mΩ. The power is thus 10,000A x 10,000A x 0.022Ω x 0.3

Take care!