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_Dear Friends,_
The leaves are falling and this morning when I took Pirate out for a walk he couldn’t resist diving into piles of leaves and burrowing. He was having so much fun that I just had to stand and watch him enjoy autumn. If it is October it is MLB playoffs and a couple of late nights as I watched my Cubbies beat the Giants to advance to the National League Championship series.
I am growing my playoff beard and will not shave until the Cubs win or are eliminated. Last time I had a beard it was dark black. It seems to be a lot whiter this time around. We have a number of baseball themed specials running this month for the boys of October and boy oh boy if the Cubs should happen to win the World Series we will have to do something really special.
Apple and Samsung are locked in a battle before the Supreme Court regarding Apple’s design patent but Apple has been enjoying some unexpected benefit from Samsung as their Galaxy Note 7 phones can’t seem to stop exploding. This will certainly increase Apple’s market share. And it should because the new iPhone 7 and iPhone 7+ are really state-of-the-art handheld computers. It seems a bit inappropriate to call them phones anymore. I would say that use as a telephone is about 20% of my use of my iPhone 7+. From alarm clock to calendar, to Siri and Maps the iPhone is a digital companion more than a phone.
This week’s Kibbles & Bytes exclusive features an Apple Factory Certified Refurbished CTO 12-inch MacBook. This Space Gray unit has an upgraded 1.3 GHz processor, 8GB of RAM and a 512GB drive. It carries the same 1-year Apple warranty as new Apple products and we are bundling it for “**Kibbles & Bytes readers**”:http://www.smalldog.com/wag900002406 with the AppleCare protection plan that not only extends the normal 1-year Apple warranty to 3 years but also extends the 90 days of free Apple technical support to 3 years as well. This week only for Kibbles & Bytes readers you can buy this MacBook and get AppleCare for free! Get the MacBook with AppleCare for only “**$1385.99!**”:http://www.smalldog.com/wag900002406
Electric Locomotion
My article last week was heavy on theory, but now that we have the theory down we can talk about some cool practical applications. All of the most interesting electrical stuff comes from combining the properties of electricity with the properties of magnetism. Electromagnets, motors, sensors and more all rely on the fundamental interactions between electricity and magnetism.
One of the most difficult things to understand are AC induction motors. DC motors are actually pretty straightforward. Even with the basic understanding a 12 year old has, I was able to repair a few DC motors when I was a kid. I would salvage them from electronics and use them to drive fans for projects like a model hovercraft and a model submarine. I tended to wear them out by driving too much power through them (and by submerging them), so I would often have to open them and repair them.
In a DC motor, the current is always flowing in the same direction. The motor itself is composed of two main pieces: the stator and the rotor. The stator is the outer shell of the motor and in DC motors, it houses fixed permanent magnets that encircle the rotor that spins inside. The rotor is composed of a shaft with electromagnets that face outwards to the permanent magnets on the stator. When current is passed through the electromagnets on the rotor, they repel the permanent magnets and rotate. Eventually though, the rotation will stop because the poles of the electromagnets and permanent magnets match up. To keep the motor spinning, we have to continuously adjust which coils are engaged. We do this with brushes that contact the rotor shaft as it spins. When it reaches a certain angle, the brushes contact a different surface and the electromagnets on the rotor are engaged one after another to keep rotation going. DC motors are inherently self-starting, meaning that the initial repulsion created will “kick” the motor into motion. That’s basically all you need to know about DC motors. Simple stuff.
AC induction motors are far more complicated, but more elegant and reliable. As we know, AC power is a constantly changing current. Standard household power is single-phase AC, meaning that there is one sine wave of voltage/current going up and down. Induction motors are actually easier to understand initially if we consider industrial 3-phase AC power. This type of power is composed of three separate AC waveforms on top of each other. Each wave is 120 degrees apart from the others.
p{text-align: center;}. !http://blog.smalldog.com/images/4851.png!
So if phase-1 peaks at time zero, phase-2 will peak 120 degrees later and phase-3 will peak 120 degrees after that. The stator of an AC induction motor is composed not of permanent magnets, but electromagnetic coils. In the simplest form, there will be three separate coils each connected to one of the three phases of the 3-phase power. The coils are physically placed 120 degrees apart from each other in the stator. Three of these complete the 360 degrees of a circle. As each coil is energized, it creates a magnetic field, and because they are arranged in a circle that is identical to the phase shift in the original power, what we have done is created a rotating magnetic field with no moving parts!
Ok, so do we put in permanent magnets on the rotor and call it a day? No need. The rotor is actually designed as something called a squirrel cage. It essentially looks like two disks held together by metal slats on the outside. Remember that because the AC power is always fluctuating, the strength of each magnetic field is fluctuating. When we place the squirrel cage inside this rotating magnetic field, the changing magnetic field ??induces?? current in the slats. This current isn’t going anywhere, it’s just trapped in the slats but like any current, it too creates a magnetic field. This magnetic field opposes the one created by the electromagnets on the stator and a force is delivered to the rotor causing it to spin. The mathematics and physics of these forces are really cool and worth checking out on your own. It’s called the Lorentz Force.
A 3-phase induction motor is inherently self-starting because regardless of the initial position of the rotor the outer magnetic field will be rotating. The power in your house is not 3-phase though, so how do those induction motors work? The principle is pretty much the same, you just have only one magnetic field to work with instead of three. Single-phase induction motors always have some way to shift the phase of the power coming in to make it off balance during startup so the motor can start. Without this the rotor would just vibrate in place. There are several ways to do this, but the most common is a starting capacitor and a secondary stator winding. This special circuit can be disengaged by a centrifugal switch once the motor spins up.
Because of their simplicity and lack of wear parts (brushes wear out on DC motors) AC induction motors are often chosen even when AC power isn’t immediately available, like in the case of modern electric cars. Their batteries provide DC power only but because AC induction motors are so advantageous, engineers actually go through the trouble of inverting the DC power to AC power. All modern diesel-electric locomotives use AC traction motors as well.
Once again, this is a difficult concept to compress, but hopefully I’ve done a bit to demystify AC motors. These kinds of motors were one of the most confusing things to me for such a long time. This was an interesting article to write, and I’m unsure what my topic will be next week. I’m thinking maybe something about inductive heating, but if any readers have any questions or suggestions, let me know!
It is time to put the Sprite and the motorcycles away for the winter. It has been a mild fall and we would probably still get some riding in if we were not heading down I-95 late next week on our way to Key West. We have a lot of buttoning up to do before we leave but the plan is to leave next Thursday and celebrate our 49th anniversary somewhere on the road. Grace and I decided to get each other kayaks for the occasion so any suggestions for some old fogies first kayak will be appreciated. Then, of course, I have to figure out how to haul them to the ocean on the Volt.
Thanks for reading this issue of Kibbles & Bytes!
Your Kibbles & Bytes Team,
_Don, Emily, Hadley & Amy_
Revert to iOS 9 Home Button Behavior
Ever since upgrading to iOS 10 and getting my iPhone 7 Plus I have been amazed with how fast the fingerprint recognition works. I must admit, however, that I was a little thrown off with having to press the Home button before unlocking my phone.
iOS 10 changes how you use the Home button to unlock your iOS device from the lock screen. Previously, you could unlock it by merely resting your finger on the Home button when the lock screen is showing. In iOS 10, however, you must press the Home button and then use Touch ID to unlock the device. With newer iPad and iPhone models, Touch ID reads your fingerprint so quickly that you can usually press the Home Button instead of just resting your finger on it.
If you’re like me and find this to be more of a hassle than convenience and prefer to skip the requirement to press the Home button I’ve got good news for you. You can change it! To revert to the previous, and one could argue faster, behavior go to **Settings>General>Accessibility>Home Button** and enable “Rest Finger to Open.”
Working Together
In a direct challenge to Google Docs, Apple has introduced collaboration to the iWork suite of apps. Pages, Numbers and Keynote now support collaboration through iCloud.
You can use iWork collaboration with these devices:
* A Mac with macOS Sierra and Pages 6.0, Numbers 4.0, or Keynote 7.0 or later
* An iPhone, iPad, or iPod touch with iOS 10 and Pages 3.0, Numbers 3.0, or Keynote 3.0 or later
* A Mac with Safari 6.0.3 or later, or Google Chrome 27.0.1 or later
* A Windows PC with Internet Explorer 11 or later, or Google Chrome 27.0.1 or laterIf you find collaboration is not available to you, make sure that you have the latest versions of the iWork apps. I have run into this issue a few times here at Small Dog. I am always a bit ahead of the rest of the team in terms of running Apple software so if I send a Pages 6.0 document sometimes I get push back from those that haven’t upgraded. I do recommend that you update to the latest versions in order to take advantage of the new features, especially collaboration.
To invite others to collaborate on your document in Pages, Numbers or Keynote you must be signed into iCloud and have iCloud Drive turned on. I was struggling a bit as we were testing this because collaboration is very dependent upon iCloud addresses. You need to use the iCloud email address to invite someone or it may get stuck in the “verification link cannot be sent” bug.
Keep in mind that the title of the document will be included in the link that you send so if it is confidential- like “www.icloud.com/pages/09aMdbLCQ5naCrMpHaqAfxUoQ#firingemily” you might want to tell the recipient to not forward that link.
p{text-align: center;}. !http://blog.smalldog.com/images/4847.jpg!
You can invite people to collaborate on your Mac, iOS device or from iCloud. To invite from the Mac simply click on the handy “collaborate” button in the menu bar. By default, people that you invite can edit your document. You can change share options and limit who can access it. If you set Who Can Access to “Anyone with the link”, and you want to add a password, click Add Password. Type your password and hint. You and other participants need this password to open the document.
Then choose how you want to invite others to work on your document. If you choose to email your invitation, type an email address or phone number for each person you want to invite. Add any other information, then send or post the message.
To invite from your iOS device, tap the ***, then tap Collaborate With Others. Again, you will be given the options to limit access or add a password. Click on Add People and you have the same choices on how to inform them via email, Messages, copying the link, Twitter or Facebook.
Inviting from iCloud in Safari is the same as doing so from within Pages on the Mac.
You may not want everyone to be able to edit the document but do want them to be able to read it. You can set this all up when you share. When you invite others to collaborate on your document, you can set restrictions on who can view and make changes to your document.
In the Who Can Access menu:
* Choose “Only people you invite” if you want only specific participants to access the document. To open it, those participants must sign in to iCloud or iCloud.com with an Apple ID. If they don’t have an Apple ID, they can create an Apple ID after you share the document with them.
* Choose “Anyone with the link” if you want anyone who has the link to the shared document to be able to open it.
In the Permissions menu:
* Choose “Can make changes” if you want anyone who can access the document to be able to edit and print it.
* Choose “View only” if you want anyone who can access the document to be able to view and print, but not edit it.
You can change share options at any time by clicking or tapping the Collaborate button, then choosing Share Options.p{text-align: center;}. !http://blog.smalldog.com/images/4848.jpg!
It is usually important to be able to track everyone’s edits on the document and know when changes have been made. If you click on the collaborate button you can see to whom the document is shared and who is currently viewing or editing it.
Edits that you and others make to the document appear in real time. Look for colored cursors and colored selections of text and objects to see what others are currently editing. Tap or click the colored dot next to the person’s name in the participant list to jump to their cursor. If you don’t see a colored dot, that person has the document open, but isn’t editing.
If you are really confident in the editors you can hide collaboration activity on your Mac by going to Choose View->Hide Collaboration Activity or View->Show Collaboration Activity. On your iPhone or iPad tap *** and turn Collaboration Activity on or off.
You can continue to edit even if you are offline but others will not see your edits until you have re-connected.
You should note that currently not all functions are available in collaboration mode. As an example, in Pages you cannot insert, cut, copy, paste, delete, duplicate, reorder or edit sections. You cannot adjust margins, use “replace all”, create delete or reorder styles.
Once you have had enough of the sharing edits on the collaborated document you can turn off sharing by clicking on the collaboration button and hitting Stop Sharing. When you stop sharing it is removed from iCloud drive for all participants.
iWork Collaboration is still in development and I expect we will see a lot of improvements before it is a real competitor to Google Docs but it is coming along. Check it out and let me know how it works for you!