Name: 為甚麼要在家裡使用交流電(AC)來代替直流電(DC)？？（Why Use AC Instead of DC at Home??）
Uploaded: 2021-07-18T16:56:30.000Z
Duration: 10 min 36 s

轉承詞

Hi. Why do we ever use AC to power homes instead of DC?

嗨，為什麼我們總是用交流電為家庭供電，而不是直流？

情態副詞

Haven't I showed you that AC is typically more dangerous than DC?

我沒有告訴過你交流電通常都比直流電危險嗎？

我們能在直流電上運行所有的東西嗎？

沒錯！事實上家裡的每台裝置都必須在使用電以前

Yes! In fact pretty much every device at home has to rectify AC into DC

先將交流電整流成直流電。所以我為什麼生氣？

first before it can use it so why? Why am I angry?

原因是很基本的。曾經，一個叫尼古拉·特斯拉的人與交流電和湯瑪斯·愛迪生的直流電發生爭執

The reason is elementary. Once there was a fight between a guy named Nikola Tesla being AC and Thomas Edison

因特斯拉贏得了他雇主西屋公司的契約，從而生產交流電

being DC and Tesla won the contract on his employer Westinghouse company to provide power with AC

無論愛迪生如何透過在公共場合電擊

no matter how hard Thomas Edison tried to expose the dangerous nature of AC by

狗和大象來揭露交流電的危險性

electrocuting dogs and elephants in public.

現在我想起我為何生氣了。這個愛迪生傢伙其實是隻動物！他還發明了用交流電驅動的電動椅

Now I remember why I'm angry; this Edison guy was an animal! He even invented the electric chair to execute with AC

並不是因為那是一種更簡單或更好的方式，而是因為他想透過將交流電和死亡連結起來來汙衊交流電。

--not because it was a cleaner or better way to execute--because he wanted to deface AC by forever associating it with death.

尼古拉·特斯拉理所當然的贏得了這場戰役

Nikola Tesla very rightfully won this battle.

沒錯，交流電可能比同等級的直流電還危險，

Yes, AC can be more dangerous than the same level DC but a higher level DC can be as dangerous

但高一點的直流電也會一樣危險

if not more and just because something is dangerous

我們並沒停止使用它。舉例，如果你住在高樓，

we don't stop using them like for example if you live in a high-rise

你不會想冒著跳下窗戶的風險。但交流電在這裡有優勢嗎？

you are not in a constant risk of jumping off the window. But is there an advantage of using AC?

我的意思是，當時他們只想使用鎢絲燈而不關心是交流或直流電

I mean, back then all they wanted was light using incandescent lights and those don't care about AC or DC.

現在我像平常一樣在直流電上運行一般的燈泡

Here I'm running a regular light bulb on AC as usual

無論如何，我正在把交流轉換成直流電藉由FUUUL

Anyways with this I'm converting the AC into DC using

它只是一個二極體，但也能使用，如果我測量它的輸出電壓

It's a single diode, but it will do and if I measure the voltage at the output

170伏特的直流電，就算一樣很危險

170 volt DC and although it's still quite dangerous

我還是可以觸摸它，而且不像觸摸120伏特的交流電一樣痛苦

I can still touch it and it's not as remotely as painful as touching the 120 volt AC

甚至更亮一點 因為它是連續的170伏特

And it's even a little brighter because it's 170 volt continues

除了燈光，電動馬達也在家裡越來越受歡迎

Beside the lights the electric motors were becoming more popular in home

像是絞肉機或風扇等 但也可以製作成無刷的

Appliances like meat grinders or fans and such, but even those could be made into brushless

直流或是有刷的交流，像是我從老微波爐取下的

AC or brushed DC for example, of course a brushless AC motor like this one that I took from an old

無刷交流馬達可以使用比有刷直流馬達更久...

microwave oven can last much longer than a brushed DC...

記得小心凌亂的電線。有刷直流馬達裡的碳刷最終還是會磨損

Loose wires, avoid them anyways brushes in DC brushed motors wear out eventually

這就是為什麼交流馬達都可以使用更久 除此之外，交流和直流似乎沒有太多的差別

And that's why AC motors can last longer, but beside that fact there doesn't seem to be much preference between AC and DC

但交流電的真正優勢並不在家裡

But the real advantage of AC is not at home

是在電還沒送到家裡時的傳送過程

It's before electricity even gets to home in transmission lines

這就是為何愛迪生的直流配電系統最終會消失的原因

And that's why Edison's DC power distribution system eventually died away, here

I made a transmission line using thin wires and using my supply

並用我的電源供應器試著在1歐姆負載上輸出10伏特10安培的電

I'll try to place 10 volts across my 1 ohm load for 10 amps of current

然後我會測量負載的電壓，讓我們來試試

And I'm measuring the voltage across my load. Let's try it

已經開始冒煙和變熱，且電壓持續地降低，看經過負載的

Transmission line is starting to smoke and heat up and the voltage continues to drop see the line resistance is so much that the voltage

線路電阻是如此的大且還到不了10伏特

Across the load doesn't even get to ten volts

像是只有7伏特7安培通過負載，且由於高電阻，它加熱得非常快

It's at seven volts for seven amps through the load and because of the high resistance. It's heating up so much

同樣的，因為愛迪生在傳輸線上傳輸低電壓，所以有大量的電流通過這些線路

Similarly because Edison was passing low voltage across the transmission lines a ton of current was passing through the lines

且在電線撐不住自身重量下或變得太貴之前，電線的細度有限

And there is a limitation to how thick you can make the wires before they break under their own weight or become too expensive

通過線路電阻的高電流將會在長距離傳輸上導致大量壓降

Huge currents through the resistance of the wire would result in large voltage drops over longer distances

這就是為什麼愛迪生的系統只能將電力傳輸到大約一英里至兩英里的地方

And that's why Edison's system could only transmit power to around a mile or two from the power source

Otherwise the power loss would be so much over the lines

那會導致巨大的反效率，當然愛迪生知道他很ㄌ*ㄢˋ的系統

That would cause huge inefficiency, of course Edison was aware of his s**tty system

所以他決定他的天才員工來解決這問題，也就是我們親愛的尼古拉·特斯拉(Tesla)

So he decided to let one of his genius employees to take care of the problem, who was our beloved Nikola Tesla

Tesla當時也在愛迪生(Edison)底下工作。 根據Tesla所說，Edison承諾他

He was working for Edison at the time. according to Tesla Edison promised him

如果Edison的DC系統有很大的改進的話，可以得到(當時的)50,000美元報酬

$50,000 which was a lot of money back then, if Tesla was able to make great improvements to Edison's DC system

Tesla在幾個月之後做到了，當去要報酬的時候

Which Tesla did in a few months and when he went to Edison to ask for the money?

他卻說：哈哈，開玩笑地。 看來你並沒有注意到我們的

He said "Haha. I was joking obviously you're not aware of our

美式幽默。 Tesla說：F*** you，我不幹了！！！

American humor," which Tesla said  "F*** you, I quit !!!"

之後Tesla想到不錯的系統並在西屋公司研發出來

Later Tesla came up with his genius system and developed it for Westinghouse company

就是讓電力傳輸更方便。他利用交流電(AC)傳輸，所以可以利用變壓器改變電壓

What he did was to transmit power much smarter. He used AC so he could change the voltage level using transformers, here

我用一台自耦變壓器(Auto Transformer)來生產10V AC，可以讓1Ω的負載產生10A電流

I'll use my auto transformer to generate 10 volt AC which would result in 10 amp AC through my 1 ohm load

But before I send it through the transmission line, first

微波爐的變壓器讓電源電壓上升，然後

I'll step the voltage up using my microwave transformer

如果我有變壓器的話，我會在另外一端讓電壓下降

and then I would step the voltage down after the line if I had a transformer

Well，我應該可以跟我們的微波爐"借"一下

Well, guess I can borrow the one from our microwave

F**k，他們使用特殊螺絲(tamper proof screws)讓我沒辦法拆開

F**k. They're using tamper proof screws to stop me

他們不知道這並沒辦法阻止我。 只是拖時間罷了。

What they don't know is that nothing can stop me. They are just postponing the inevitable

在拿出來之前先拍一張接線圖。我不想等等就把它炸飛了

I'll just take a picture of the wiring before I pull it out. I don't want to blow it up later

OK，接好線了。 在接上負載之前先量一下電壓

Ok, now we have both transformers connected. Let's do some voltage measurements before I connect the load. At the input

輸入有大概10V，不錯。 在線路上...

We have close to 10 volts so that's good. On the transmission line

We get around 190-200 volts. And at the output

也有大概10V，非常好。 現在把負載接上去

Again we have close to 10 volts so that's pretty good. Now, let's connect a load

1.6V?這垃圾發生什麼事? 線路上的電壓呢

1.6 volts? That's garbage. What happened? The transmission line voltage

這比DC傳輸還差。Tesla發生什麼事了? 量一下變壓器次級圈的電阻好了

This is worse than the DC system. What's going on Tesla? Let's measure the transformer secondary winding resistance

次級圈電阻太大以至於電壓降太多了，所以這些變壓器並不是這個用途的

There's too much drop over the large resistance of the secondary, so these transformers are not made for this purpose

這不是好得範例。不管它了。我還是要傳輸電力

That was a bad example. It doesn't matter. I'm gonna transmit power. No matter what

And our transmission line is not burning so that's always a plus

沒有東西炸掉。現在線路電壓多少?

Nothing is exploding. What is the transmission line voltage now?

雖然這是很糟糕的實驗，但是我用

This is a pretty bad example, you can see that

I'm transmitting more power than the DC system

但是線路沒有燒起來。 所以這算是某方面的成功?