Sep 29, 2003, 09:55 PM Registered User Jefferson, GA Joined Jul 2002 1,220 Posts Brushless terms..What does # of turns mean? Could someone please explain what it meant by the "number of turns" in relation to brushless motors? Please explain what this represents or measures, and what the result is of having a higher or lower number. Thank you, David J.
 Sep 29, 2003, 10:12 PM Just an average RC'er Laurel, Maryland USA Joined Aug 2000 4,291 Posts The number of turns affects the RPM per Volt of the motor. The fewer the turns the higher the RPM per Volt, more turns has fewer RPM per volt. The trade off is that the lower turn motor will have less torque, while the higher turn motor will have more torque. In general the difference in torque is not directly proprotional to the RPM/V. That means that lower turn motors will have more torque per RPM, but it's not a huge difference. Another difference is that lower turn motors usually have thicker wire and can handle a little more current, becuase of this they will also have a lower impedance and thus less heat generation at a given power level. -Jim
Sep 30, 2003, 12:17 AM
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Los Angeles, California
Joined Apr 2002
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Quote:
 Originally posted by Jim McPherson The number of turns affects the RPM per Volt of the motor. The fewer the turns the higher the RPM per Volt, more turns has fewer RPM per volt. The trade off is that the lower turn motor will have less torque, while the higher turn motor will have more torque. In general the difference in torque is not directly proprotional to the RPM/V. That means that lower turn motors will have more torque per RPM, but it's not a huge difference. Another difference is that lower turn motors usually have thicker wire and can handle a little more current, becuase of this they will also have a lower impedance and thus less heat generation at a given power level. -Jim
Jim,

I think I understand the general usage of the number of turns in brushless motors. However, what does "turn" refer to? Also, in brushed motor, there is also a reference to "wind". What does "wind" refer to and what is the relationship to "turn"? Does "wind" apply to brushless motor too? Since I don't see "single wind", "triple wind" etc. being mentioned in the brushless world.
 Sep 30, 2003, 01:28 AM Just an average RC'er Laurel, Maryland USA Joined Aug 2000 4,291 Posts Turn is the number of times the wire goes around the stator tooth (assuming a stator exists). In the car world the term wind is synonymus with turns. Single wind, double wind etc. means that instead of one wire going around each stator tooth there are two (double) or three (triple). The two wires are effectively acting as one, except that because they are actually 2 wires you can fit more copper into a smaller place. Many brushless motors are wired in this manner(my AXI and Mega motors do this) they just are not advertised as such. -Jim Last edited by Jim McPherson; Sep 30, 2003 at 01:31 AM.
 Sep 30, 2003, 01:32 AM Registered User Germany Joined Sep 2003 77 Posts Turns and winds are the same. In brushless-world it means how many times the wire(s) is/are wound around ONE tooth . If one won't handle one thick wire, he uses "double" or " triple" wires parallel (each with smaller diameter). regards Olaf
 Sep 30, 2003, 10:14 AM Registered User Los Angeles, California Joined Apr 2002 923 Posts This is great information. DavidJ, I am sorry if it sounds like I hi-jacked your thread but you brought up a question that I never gave any deep thinking of unitl now. And here we go, more questions. Is it not true that all brushless motors then are single wind? There are only 3 wires coming out of the motor. If they are double wind or triple wind, would you not see 3 sets of double wires or triple wires? If everything else is equal, what do you get or lose with more or less winds?
 Sep 30, 2003, 12:19 PM Registered User Ontario, Canada Joined Nov 2002 1,568 Posts Disagree... Contrary to Olaf's comment... - "Turns" refers to how many times the wire(s) are wrapped around the armature (or stator in a brushless) - "Wind" refers to the number of parallel wires that are used carry the current, usually one, sometimes more. The reality of turn/wind combinations are a bit of voodoo science (particularly in 540-size car motors). The general rule seems to be that multiple thinner wires (versus one thick one) makes a motor that offers more torque versus higher RPM capabilities. But, the entire operating "premise" for R/C cars is a fixed-voltage world, utterly different than R/C aircraft. Perhaps a BL expert can chime in and give us some details?
 Sep 30, 2003, 02:02 PM Just an average RC'er Laurel, Maryland USA Joined Aug 2000 4,291 Posts aau007: No, many brushless motors have multiple winds however they are all combined inside the wires that you solder to. I am looking at an AXI 2808/24 right now that is double wind. -Jim
 Sep 30, 2003, 03:10 PM WORK! Joined Jul 2002 407 Posts Does this terminology correlate to the voltage of a brushed motor? I see different voltages for the same size motor like s400 4.8v, s400 6v, s400 7.2v. I understand that a higher voltage motor can handle more cells, the lower voltage motors generate higher rpm per volt but don't know exactly why. Thanks, Howard
 Sep 30, 2003, 06:44 PM Registered User Ontario, Canada Joined Nov 2002 1,568 Posts Food for thought... (actually very important!) Here more than you want to know, from the guys at Aveox: http://www.aveox.com/torque.html What's very interesting is the statement: "...Since the construction of the motors are identical, except for the number of turns on the armature, ALL of these motors can produce the same output torque!" This kind of kills the common "understanding" that there is such a thing as a "hi-torque" or "low-torque" motor. (within a specific range of motors like the Mega 16/15/x, etc) Really the difference in turns is where that maximum torque point occurs in relation to current (A) going in to the motor, in response to an applied load. A low-turn motor can "use" (bad terminolgy!) more amps to attain maximum torque, a high-turn motor uses less to reach maximum torque. It's the old "watts are watts" axiom, as long as you load the motor to the torque peak (current), the voltage you apply is really irrelevant, unless you reach the thermal or mechanical limits of the motor. Bottom line: when choosing a particular number of turns, no one number of turns is more "powerful" than any other, that's strictly a function of voltage. Very cool!
 Oct 01, 2003, 03:35 AM Registered User East Anglia, UK Joined Sep 2002 29,713 Posts Torque is not power. Hotter wound motors will do best power at lower voltages. Hotter wound motors may alos be more efficient - certainly at lower voltages. There is a lot to consider, but best power out of a motor is at max RPM it doesn't disintegrate at, and max current that doesn't fry the windings. Hotter wind menas you can put more current through, and it will scream up to max RPM on small cell count. To get same power on 'cool' motor takes more cells. Then it will indeed have same RPM, and same toruue at less current. In reality, taking something like MEGA motors, a 16/15/3 will approach max power at 8 cells or so, whereas teh cooler motors really need far more cells than people run em at to get to teh same power levels. In reality, those coooler motors run at less power (but excellent afficiency) to swing bigger props DD. No one says you have to run a motor at max theorteical power before damage! However for best power-to-weight, sometimes you want to.