Circuit design to switch on local power during global outage

[beltscientist]

Can you help me out? I’m looking for a circuit design to switch on local power during a global power outage.

Like if there is a steam engine near the coal miners that is normally off, but when the power goes off, it needs to switch on.

[wobbycarly]

This might help with some inspiration: https://wiki.factorio.com/Tutorial:Circ ... team_power

[quyxkh]

A canary accumulator on the main power net but not on the emergency net should do it, canary charge <25% throw the isolation switch and turn on the emergency power.

[Tertius]

I recommend you don't build emergency power plants that do nothing in 95% of the time, and if you switch them on you will find they're insufficient anyway. It's a waste to build a power plant that's not being used.
Instead, build two power grids, one core grid for essential machines and another for non-essential factory parts. The first includes all power plants, fuel, ammo supply, mall. The other includes everything research-related. This is where the most energy is consumed. Connect the two with a power switch.
Then, if you detect a brownout, switch off the power switch and your core grid has enough power again to operate properly, for example to still power your lasers for border defense. This gives you all the time you need to build an additional power plant.

[beltscientist]

Thanks - that's helpful.

Is there a way to test my design? To create a circuit that would take a full power level and output a power level less than 100%?

[astroshak]

As they said, a single Accumulator will do the trick, if in a simple-minded manner. Wire it to a power switch, and have the switch on when A >25 (or off when A < 25, whichever based on the interface). If you want to prevent hysterisis, use a SR Latch for when to turn it off/on.

There is another option though … wire the accumulator to your boilers’ offshore pumps. Have the offshore pumps come on when the Accumulator charge gets low. This provides near instant reaction time, provided that you keep fuel on the belts for the boilers. However, hysterosis still applies, so a SR Latch is again recommended.

But, in all honesty, the best approach is to forego backup power plants entirely. Just overbuild your main power plant. Planning an expansion? Check your power situation; if demand is anywhere near, or above, 50% of your power plant’s capacity, better to expand the power plant first.

[SirSmuggler]

But, in all honesty, the best approach is to forego backup power plants entirely. Just overbuild your main power plant. Planning an expansion? Check your power situation; if demand is anywhere near, or above, 50% of your power plant’s capacity, better to expand the power plant first.

You are not wrong, however... Building uneccassary contraptions, such as a backup power plant, is (for me) a big part of what makes this game so much fun!