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by eigenvector 1918 days ago
The ostensible benefit to DC distribution in homes is to be more economical and simpler for devices that already run on DC - not to redesign ever device ever made to accept mains-voltage DC. If your iPad and your laptop and your blender still need a power brick to work, what's the point?

Using high-voltage unnecessarily to avoid using a DC converter is also not going to save money. Yeah, you can use a 300 V DC motor in a coffee grinder, but why? It's just going to cost more money to make.
2 comments
londons_explore 1918 days ago
90% of things in your home would happily run from 150V DC, even though they aren't rated for it.

Source: I sometimes connect my solar panels direct to my AC wiring without an inverter, and my house works entirely except my washing machine and fridge (both of which have AC motors in). Even my vacuum cleaner works (although it's on-off switch doesn't work, since it uses a thrysistor!). Phone charger, laptop charger, oven, microwave, doorbell, furnace, routers, TV, monitors, desktop pc, all work fine.

If some country declared tomorrow that all electrical devices must accept AC or DC, not that much would have to change.

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interestica 1918 days ago
I had no idea about this. Can it damage things that won't work (eg things with AC motors). I've been building out electrical in a campervan and always wonder if there were DC equivalents to a lot of things.
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londons_explore 1917 days ago
Yes. AC motors will normally blow their fuses immediately.

But a small AC motor (eg. a fishtank water pump) will burn out before the fuse blows.

Surge protector strips sometimes have isolation transformers. These will also blow their fuses immediately.

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namibj 1917 days ago
My point is, that the European accidentally-DC-capable mains equipment can be expected to complain/sustain overcurrent damage, provided it isn't able to handle US residential voltages.

Hence you might as well take the opportunity and switch to a higher in-house distribution voltage than the typical 120 V.

And that 300 V DC motor may actually be cheaper, as you could run a BLDC driver directly from the DC supply with just minimal filtering.

The enhanced power density and copper-efficiency of these high-frequency 3-phase motors may make up for the cost of said inverter, even neglecting the considerably increased energy efficiency over a typical single-phase-capable "oldschool" motor.

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