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I'll try to explain some of the workings of our motors as best I understand it, and show how I go about rewinding a stator. I feel that I need to lay down some basics about the internals of the motors first. And to describe some of the terminology, so that we all understand each other without getting to confused. I'll capitalize the main parts when I describe them so pay attention to what I'm naming parts so we wont get confused later. And please call me out on something if you think I'm wrong or describing it incorrectly. I have not been schooled on any of this, it's just what I have learned on my own by reading and rewinding a couple of motors. And to give you an idea of how many motors that I have rewound so far. I just bought my 8th, 5 pound spool of wire. Each spool has 7850 feet of wire on it! 62800 feet or just shy of 12 miles! I am NOT claiming to know everything there is to know about these motors, but I do have a pretty good understanding of how they work and how too wind them.
There aren't very many parts inside and I'll assume that ya'll know what a rotor is. So the main thing to explain is the stator and windings.
The STATOR as I'm sure most of you know is the big chunk of steel surrounding the rotor. It holds the wires or BUNDLES of wires that are threaded through holes in the stator, called SLOTS. The wire goes through the slots and wraps around the stators TEETH, maybe just around one tooth, as in a CONCENTRATED wind. Or the wire can go around three teeth as in a DISTRIBUTED wind, More about this a lot later in this thread. When the wire goes through those slots, and wraps around those teeth, it does so in a particular couple of ways. One is that the wire will go around and round said tooth to form a COIL. This coil can be either one wire, or several wires that are eventually connected on both ends so as to act like one larger wire, and this is what I refer to as a BUNDLE. We have to use the bundle because we can't get just one big wire through the slots and make the 180* turn to go down the next slot. One big wire would be better but it ain't gonna happen! So when you make this coil you might wind it clockwise or counter clockwise. And ya better get it right! You'll be able to see on some of my pictures later, that the wind is following a certain CW or CCW pattern. Most of the winds that I use follow this CW or CCW pattern all the way around the stator. BUT THEN sometimes you get one that will have both CW and CCW in the same stator and it can get a little confusing. The Dynamite 3831 2000 kv 3 delta motor, is an example of this type of wind. (that last sentence has a "misprint" in it that I hope someone catches and points out)!
The reason for the CW and CCW explanation is, if you connect a battery to a coil one wire on positive, and the other on the negative (don't know how you'd do it any other way
) and the coil has a hole through the middle. And now insert a steel rod through that hole, or wrap the wire coil around a screwdriver. Take a magnet and hold it to the ends of the rod, making sure to use only one side (pole) of that magnet. You notice that the electro magnet that you made with the coil and rod has a north and a south. NOW switch the polarity of the wires going to your coil,and check the rod ends again, using that same side (pole) of the magnet. you'll see that the poles of the electro magnet have switched! Amazing isn't it!
So in the coils that we made in our stator, lets say we made them all CCW, and so when the esc sends these coils a positive signal, lets say the stator teeth turn into north poles. This attracts the south pole magnets on the rotor. Just as the rotor gets about lined up on that position, the esc switches (commutates) and sends a negative signal to the coils, and this changes our stator coil teeth to a south pole, and thus attracts the upcoming north pole on the rotor! This is a very simplified explanation and not real accurate, because ther will be positive and negative charges flowing at the same time. And there will be north and south coils working at the same time too. And don't forget that third set of coils that aren't being energized, but instead are making electricty and sending a pulse back to the esc saying, here I am send positive down that wire--now here I am send negative down that wire-- now I'm over here do this. That esc is a smart and fast little sucker.
The STATOR has an insulating coating on it to keep the windings from shorting between legs/phases. We have three wires going from the esc to the motor and these are what we'll call LEGs or PHASEs. I don't think that is an accurate way to describe them because on a true AC (alternating current) 3 phase electrical circuit, all three phases are hot . Not so on our DC brushless system. Two legs are hot, from the positive and negative poles of the battery/esc, and the third leg is carrying a "signal voltage" from the motor windings, back to the esc, called BACK EMF (electromotive force) generated by the third legs coil. This signal tells the esc what position the rotor is in, in it's rotation, so that the esc knows which set of coils to fire next.
There aren't very many parts inside and I'll assume that ya'll know what a rotor is. So the main thing to explain is the stator and windings.
The STATOR as I'm sure most of you know is the big chunk of steel surrounding the rotor. It holds the wires or BUNDLES of wires that are threaded through holes in the stator, called SLOTS. The wire goes through the slots and wraps around the stators TEETH, maybe just around one tooth, as in a CONCENTRATED wind. Or the wire can go around three teeth as in a DISTRIBUTED wind, More about this a lot later in this thread. When the wire goes through those slots, and wraps around those teeth, it does so in a particular couple of ways. One is that the wire will go around and round said tooth to form a COIL. This coil can be either one wire, or several wires that are eventually connected on both ends so as to act like one larger wire, and this is what I refer to as a BUNDLE. We have to use the bundle because we can't get just one big wire through the slots and make the 180* turn to go down the next slot. One big wire would be better but it ain't gonna happen! So when you make this coil you might wind it clockwise or counter clockwise. And ya better get it right! You'll be able to see on some of my pictures later, that the wind is following a certain CW or CCW pattern. Most of the winds that I use follow this CW or CCW pattern all the way around the stator. BUT THEN sometimes you get one that will have both CW and CCW in the same stator and it can get a little confusing. The Dynamite 3831 2000 kv 3 delta motor, is an example of this type of wind. (that last sentence has a "misprint" in it that I hope someone catches and points out)!
The reason for the CW and CCW explanation is, if you connect a battery to a coil one wire on positive, and the other on the negative (don't know how you'd do it any other way
) and the coil has a hole through the middle. And now insert a steel rod through that hole, or wrap the wire coil around a screwdriver. Take a magnet and hold it to the ends of the rod, making sure to use only one side (pole) of that magnet. You notice that the electro magnet that you made with the coil and rod has a north and a south. NOW switch the polarity of the wires going to your coil,and check the rod ends again, using that same side (pole) of the magnet. you'll see that the poles of the electro magnet have switched! Amazing isn't it!So in the coils that we made in our stator, lets say we made them all CCW, and so when the esc sends these coils a positive signal, lets say the stator teeth turn into north poles. This attracts the south pole magnets on the rotor. Just as the rotor gets about lined up on that position, the esc switches (commutates) and sends a negative signal to the coils, and this changes our stator coil teeth to a south pole, and thus attracts the upcoming north pole on the rotor! This is a very simplified explanation and not real accurate, because ther will be positive and negative charges flowing at the same time. And there will be north and south coils working at the same time too. And don't forget that third set of coils that aren't being energized, but instead are making electricty and sending a pulse back to the esc saying, here I am send positive down that wire--now here I am send negative down that wire-- now I'm over here do this. That esc is a smart and fast little sucker.
The STATOR has an insulating coating on it to keep the windings from shorting between legs/phases. We have three wires going from the esc to the motor and these are what we'll call LEGs or PHASEs. I don't think that is an accurate way to describe them because on a true AC (alternating current) 3 phase electrical circuit, all three phases are hot . Not so on our DC brushless system. Two legs are hot, from the positive and negative poles of the battery/esc, and the third leg is carrying a "signal voltage" from the motor windings, back to the esc, called BACK EMF (electromotive force) generated by the third legs coil. This signal tells the esc what position the rotor is in, in it's rotation, so that the esc knows which set of coils to fire next.
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