How many AC motors do you have at home? Mine are almost all (barring my big woodworking machines) universal motors. Even the old shaded-pole motors in clocks and timers have gone digital now.
It's still a terrible idea though. Switching tens of DC amps isn't that easy.
Avionics is very safety conscious, so it tends to evolve rather than innovate. 115V 3-phase alternators are already in service, so the only significant mod is just a rectifier stack.
Yes, although it's not simply a matter of tripping the breaker, but tripping it within the required time (0.4 seconds for circuits with socket outlets, 5 seconds for other circuits).
No. Whole house RCD is not permitted (except >=100mA as described above, and only when really required). I described which circuits are required to be RCD protected (at
The 800Hz hum from a transformer core or motor sounds real nice, too. Not.
Either 50 or 60 Hz is fine. But I'd like to see 480V 3ph in a house. 3 phase, of whatever voltage or frequency will do more for motor efficiency than the other factors.
Sometimes I forget that normal people have no need for the types of motors I'm used to. Since I'm mainly concentrating on industrial construction right now, my mind kind of kept going with everything I'm familiar with.
I read up on this in detail a while back, might have started from the wiki ACFI page. In brief, higher v means both lower run current and higher fault current, producing very much better fault discrimination and fault clearance. There is also the lesser point that some faults dissipate less heat on higher v.
There is NO limit to the number of outlets per circuit in the US. The only limit is the number that will fit on the floors, walls and ceiling of a room and the budget.
Ditto
Our regulations are a MINIMUM requirement not a specification.
Cord length on US kitchen appliances has nothing to do with fault protection!
The concern is the cord not being long enough for the excess to hang over the front edge of the worktop and therby allow a toddler to pull the appliance down upon themselves (with obvious non-electrical consequences).
It's a rhetorical question anyway. There is no place on the planet that does not already have electric service in some form or another, so anything you would impose would need to match waht is already there. You cannot "start from scratch" any more. No matter what you do, you will have problems and benefits based upon what is already in existance. A better approach is to look at your most important likely trading partner. If that is going to be the US, i.e. you are going to be importing machinery and appliances from US suppliers and your populace is going to travel back and forth a lot, use 120/240 60Hz. If not, use 220 50Hz. All other arguments are pointless.
Anyway, you can make a three phase inverter for AC motors to run on DC fairly cheaply.
My real point was that with the advances in semiconductors, making AC from DC and voltage transformation is not really a huge issue as it was in the 20's when all the grid went in.
Modern appliances either have a way of shortening the cord (our kettle base has an area to wind the excess cord, and the deep fryer has a winding area too; yes, these are meant to be used when they are 'running'), OR they have 'curly' flex.
400Hz is useful for aircraft because of weight/volume/power considerations but these don't apply. Also 400Hz in home would require frequency converters (extra $$$) as distribution is not particularly practical at this frequency in comparison to 60Hz or below. As for 100V, again why? What gain is made?
The proper answer to the original question is "it depends"
Agreed-partially. While 400Hz requires less iron in a motor, the problem is that, for the speeds of typical household motors, we are looking at much higher synchronous speeds- many more poles. Possibly a large diameter pancake or simply use "brushless DC". Same control problem with that as with a 60Hz supply. Transmission at 400Hz has its problems anywhere where distances are large or L and C are appreciable. so that at local substations there would have to be frequency converter stations- not cheap. May as well go half-way and go DC for less$$.
Now, 480V, 3 phase, sounds good at either 50 or 60Hz.
-- C'mon now, APL isn't that bad to read unless you want to show off with recursive one-liners! At least one can concentrate on the problem rather than the code.
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