Page 5 : Cores and Coils - Continued 蕊心與線圈 (續)

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原文: http://www.totallyamped.net/adams/page5.html

在這一頁要開始來討論線圈的配置和磁鐵的特性。 This will eventually lead us to rotor design; since how or what you want your motor to do will dictate the design of your rotor as well. In Fig 13 below we'll look at various coil locations, and discuss some observations. Lets go MYTHBUSTING !

在上面的 Fig 13 中，有一個驅動線圈和兩個拾取線圈。馬達啟動後而且平順的轉動著，此時測量Coil B 和 Coil C的電壓。我們會發現，雖然兩個線圈在各方面全都一模一樣，但是Coil C 的 Voltage 會比 Coil B 高。這是你昨晚夢到的 "Sweet Spot" 嗎? (LOL). 當你將 Coil C 移向 Coil B 而遠離 Coil A，你會注意到電壓開始下降，直到一半的地方，你會注意到幾乎就和 Coil B 一樣。但是當你更靠近 Coil B，Coil C 和 Coil B 的電壓可能同時都會一起上升，但是不會變成和 Coil C 的電壓一樣高，亦即在靠近 Coil A (驅動線圈) 的位置。

What's going on here ?? Simple induction, that's all: - represented by the green lines around Coils A and C. There's no Punch without Judy! You cant stick one core near another, without shielding, and not have something happen between them when one or more is energized. Especially when the magnetic path between them is constantly changing due to a magnet swinging past at high speed. The magnet, as it passes from Coil A to Coil C is imparting some of the EMF and CEMF from Coil A on the leading and trailing edges of the pulse. Remember Coil A is turning on and off which is inducing a changing field exchange with Coil C . All the while this process of induction by proximity is happily facilitated by the closing of one end of the magnetic circuit between them by the magnet as it passes between them. So the higher Voltage reading is due to the Magnet and EMF/CEMF of Coil A combined. When Coil C is shifted right around to close proximity to Coil B, a field becomes shared between them which is induced by the magnet, and a similar sharing of Induced EMF occurs. Though not as profound, because neither coil is externally energized by a power supply like Coil A.

But what comes in goes out. If you connect the outputs of each coil to a load, then, when Coil C is near Coil A (the drive coil) it will deliver a higher power to the load. But the extra power will be drawn directly through induction from the drive Coil A, whilst Coil B will only deliver what it gets from the rotating magnet. When Coil C is near Coil B, they will both only deliver the same amount of energy as each other and the total energy combined will be less than the combination of Coil C and Coil A. This is because they are both now only receiving induced current from the magnet and not from Coil A. There is no "Sweet Spot" here without a sticky end. The higher power combination of Coil A and C together, fed into a load , results in higher current consumption from the driving source. In this case a battery supply.

在下面的 Fig 14，我們要看看另外的， 不同類型的 "Sweet Spot "。下面將參照 Fig 14 來說明這個 "Sweet Spot"。

In Fig 14 above, we move the pickup Coil B towards and away from the moving rotor. All the while we are measuring the AC Voltage output of Coil B. Starting at about 1.5 centimeters away from the rotor, we notice we have a 1Volt peak to peak AC signal, and as we slowly push the core closer to the rotor we witness the voltage increase steadily until we are about 2-3 mm away from the rotor, and reach a Voltage of about 3.0 Volts. As we were moving the core closer to the rotor, we also noticed that the rotor slowed down just a "little bit".

At 2-3 mm distance, we continue to push the coil closer to the rotor, and at first notice a slight increase in Voltage, but then all of a sudden the rotor begins to slow down significantly and the Voltage suddenly starts to drop off. As we slowly pull back on the coil and return it to the point where it was about 2-3 mm away, we notice the rotor regains its speed and the Voltage climbs back up to 3 Volts. Is this the "Sweet Spot" you dreamed about last night? (LOL). Well it might be, because it is a "Sweet Spot" in a sense. It is not a magical "OU" realm, but it is the right spot for your particular setup. The actual distance will depend on both the magnet strength and length and the nature of the core being used. But this particular "Sweet Spot" is present in all open magnetic systems. It does not affect Air Cored Coils until those coils are delivering current into a load. Even when that is the case, the effect is minimal on Air Cored Coils.

要瞭解這個，我們必需要討論 "bloch wall (布洛希磁壁) " 和 "transition wall (過渡壁) "，後者我們還沒有討論過。下面的 Fig 15 代表 Transition Wall 的示意圖。

在上面的 Fig 15 中的兩個 group 中，磁鐵在左邊，線圈在右邊，其已變成感應磁鐵。但是 group A 和 B 是有差異的。

在 Fig 15 A 中，磁鐵和感應磁鐵的表現仍是個別的磁鐵。此感應磁鐵的存在是依賴於該磁鐵，但其在各方面看來就是該磁鐵的鏡像，除了絕對強度較弱之外。隨著磁鐵和線圈更靠近，bloch wall 會移向它們的共同中點，也就是 transition wall。這只會出現在兩個或兩個以上的磁鐵之間，或者出現在磁鐵和其感應線圈之間。獨自一個磁鐵，沒有其它東西和它玩的時候，根本就不會如此! "或是當兩個磁鐵變成一個磁鐵的時候!"

在 Fig 15 B 中，磁鐵移到這麼的靠近磁鐵，突破了彼此的 transition wall，已經完全落在磁鐵的壓倒性影響的範圍內。兩個分開的個體，對於所有的磁性含義或意圖，已經變成 "像是一體"! 隨著整個線圈變成單一磁極後，感應 bloch wall 不見了，並且磁鐵的 bloch wall 向前挺進，藉以宣稱其新找到的主控位置。現在要將線圈和磁鐵分開變得很困難了，即使它們甚至還沒實際接觸在一起! 此改變是一種量子變化，其需要在驅動功率的躍進 (leap) 才能維持轉子的轉速。現在，磁性狀態的改變影響了將這兩個元件分開所牽涉的壓迫因素。

When water changes to ice there is a quantum change in state to the individual water molecules. Think of the way that water has a "latent" heat quota, which must be extracted before it will turn to ice, (relate to creating electrical Coercion). Once it does turn to ice, that same latent heat quota must be filled (relate to creating Drag) before it will turn back into water again. All the while, you could have just left it alone, and you would have had a drink of water a whole lot quicker!

強烈建議將你的拾取線圈週整到 "Right Spot"。 You will get the maximum Voltage and Current without paying a greater price than you need to. I also recommend, that you start off your construction by mounting your Drive Coils first. Play around with the Drive coils to "tune them in" to the "Right Spot", which is the best distance from the rotor. The best distance in this case, will be when you are getting the Maximum desirable RPM from a Minimum Current Draw for that given Maximum desirable RPM. Then, mount your pick-up coils and tune them in to the best distance that suits them. If the Drive Coils and Pick-Up Coils are identical, then the best distance will be the same for both coil types.

Standard Electrical Induction Generator Theory says you should put the cores as close as possible. In this instance I strongly disagree. I say put them where you get the most Voltage before your rotor slows significantly. And remember - This is an Open Magnetic System and We Play by Different Rules here! What can appear to be a weakness can be a great strength. There is a "yet to be discussed anomaly" which makes good use of the changing Bloch and Transition walls.

在前進到使用 Singular 和 Bi-Filar 線圈的工作模型之前，讓我們再看一下 "Sweet Spot"。馬達控制電路的 Hall IC 是負責在正確的時間切換脈波的 on 和 off ，下面的 Fig 16 繪示當 Hall IC 的位置移動造成點火的 "脈波角度 (pulse angle)" 改變時預期會得到的不同結果。

在上面的 Fig 16，在轉子的一側裝設單一的驅動線圈，負責開關作用的 Hall IC 則在轉子相對的一側。此校準線是為了方便顯示改變 Hall IC 的點火角度所建立的不同 "Zones"。在 point A，IC 是在磁鐵和線圈的 "register point" 的線上。隨著你將 IC 由 register point 移往 point B，你會發現馬達的 RPM 並未降低，或者只是稍微降低一些，但是驅動電流也稍微減少。當你通過 point B，並且繼續接近 point C，你會注意到 RPM 會很快的降得更多，而且驅動電流會開始增加的更快。假如你再通過 point C，RPM 會急速的下降而且驅動電流的消耗也會急速的增加。

為了得到最高的 RPM 和真正的轉矩，Hall IC 在剛過 register point 但不超過 point B 的位置，馬達會運轉的最好。在那個小小的角度範圍內是你的馬達的最佳角度。實際的角度是無法預測的，沒有適用於所有馬達的固定角度，其會依據其他許多因素而變化的，例如所使用的磁鐵的寬度與磁鐵間的間隔的關係 (duty cycle)，還有磁鐵的強度，Hall 的偏壓，等等。你所要做的就是，測量 Hall IC 在不同位置時的電流消耗，你會找到可獲取最大 RPM 和轉矩而且是最小驅動電流的角度。

在 point B 和 C 之間，會有一個馬達的動力轉換，其會將轉矩效益 (torque availability) 轉換成 CEMF效益 (CEMF availability)。 Now there is always going to be a level of CEMF available while the coil is pulsing on and off. But the maximum level of usable CEMF (note* - current: not just potential) can be found when the motor is slightly "de-tuned" and your Hall IC is somewhere in the zone between B and C. But as mentioned, there will be a slight increase in current consumption, and a decrease in true torque.

你也會注意到 point D。假如在啟動之前 Hall IC 就在這個位置，那麼當電路接上的時候，轉子會反時鐘方向轉動。但是，要是馬達已經順時鐘方向轉動，那麼 Hall IC 在 point A 和 D 之間會發生什麼事呢? 對於反方向越過 register 的很小的角度，轉動中的馬達是相當容許的，仍然會高轉速運轉的。在這裡會注意到一件事，就是在這小小的區域，其作用與 points B 和 C之間是一樣的。

到這裡，你應該開始看得出來設計 "Adams" motor 時要考慮的東西比你原先預期的還要多的多。究竟什麼是你想要由這馬達得到的呢? 如我先前提過的，這是一個非常 "動態的 (Dynamic)" 馬達，從這個字的各種意義來看，此馬達的設計就看你想要由它得到什麼。但是這種馬達的構造簡單，製作相當容易，用它們來作實驗是很棒的。一般來講，透過這種馬達的實驗可以學到很多關於馬達的知識，並且也可以用來向初學者介紹簡單的半導體電子學原理。

接下來.......To Bi or not to Bi ?