| Electronics > Beginners |
| Is there a particular reason Japan is 100 volts? |
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| GeorgeOfTheJungle:
--- Quote from: rstofer on August 30, 2018, 01:08:02 pm ---60 Hz is our competitive advantage over the 50 Hz world. It takes less iron to make motors and transformers thus saving costs. --- End quote --- I still remember that in the past, all the US wall chargers, those that had iron transformers inside, ran crazy hot in Europe, due to that. There are more hysteresis and eddy-current losses, and the lower voltage means you need more copper in the wirings everywhere, and/or more I2R losses. |
| mmagin:
--- Quote from: filssavi on August 30, 2018, 02:29:31 pm ---The only switch that would kind of make sense with the current state of power electronic would be to switch from AC to DC for distribution, not regular transmission, there AC is still going strong for now. The great majority of loads right now (I don't have numbers but I bet is over 80% of the total residental and small industrial installed power) rectify the AC to DC anyway, and especially in residential use the conversion efficiencies are quite low. --- End quote --- So, uh, like distributing 120-160 VDC (or equivalently 240-320 VDC)? You'd need more expensive circuit breakers / fuses. Also you'd have a harder time detecting ground faults (and such faults would lead to corrosion issues). And it only saves on the initial PFC/rectification part of a power supply. Something lower voltage? (5, 12, 48, etc?) Going to be spending a lot on copper wire. |
| filssavi:
The more expensive breaker /fuses ok that is a disadvantage. I fail however to see how detecting a DC ground current with modern technology is significantly harder than with AC, it could be more expensive I give you that but not that much harder and not having rectifiers/PFC stages can save quite a lot of energy, granted there is little power lost in each device but you could eliminate them from the vast majority of electronics on earth, so the tiny contributions start adding up fast. However the real problem is that a switch would be way too expensive (basically we are talking of replacing almost the whole distribution grid at once), so it will never happen |
| rstofer:
--- Quote from: filssavi on August 30, 2018, 02:29:31 pm ---The only switch that would kind of make sense with the current state of power electronic would be to switch from AC to DC for distribution, not regular transmission, there AC is still going strong for now. The great majority of loads right now (I don't have numbers but I bet is over 80% of the total residental and small industrial installed power) rectify the AC to DC anyway, and especially in residential use the conversion efficiencies are quite low. switches will get bigger but they are being replaced by semiconductors anyway Circuit creakers will get bigger, but it is not the end of the world Unfortunately this will probably never happen since the costs would be way to high and so we will keep 240V/50Hz or 120V/60Hz forever I think --- End quote --- Actually, DC transmission is done extensively in Europe and makes a lot of sense. But transmission is easy, it's usually just about point to point and both ends can agree on the voltage. https://en.wikipedia.org/wiki/High-voltage_direct_current Distribution is usually at some intermediate voltage (say 12 kV just to pick a number) and this is what is in the ground or on the poles. Somehow we need to get that down to a low voltage that is suitable for residential use and that takes transformers of one kind or another. With DC that is just about impossible (actually, it may actually be impossible) and that's why we need AC in distribution and utilization. Don't bet on residential as being primarily DC capable. My HVAC system won't run on DC. Nor will any of my ceiling fans or even the microwave. The stove and oven (seldom used) could possibly be DC as could lighting. But a high percentage of my bill comes from cooling. In most ways, I would rather we have the system they have in Europe where they get 3 phase 240/415 (or something similar) because we could then use 3 phase motors. But I would prefer we stay at 60 Hz. None of which is going to happen any time soon. |
| rx8pilot:
In Japan, they use metric volts. Short and misplld from my mobile...... |
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