motor turns
10-17-2011, 10:04 PM
#2
RE: motor turns
ORIGINAL: sjhm9102
hi whats the diference in motor turns i.e 10 turn 12 ,21 ,23 which is fastest and drawbacks
hi whats the diference in motor turns i.e 10 turn 12 ,21 ,23 which is fastest and drawbacks
less turns = exact oppositeof more turns
really should use the search function this have been cover a billion times and thats probably not an exaderation.
10-17-2011, 11:39 PM
#3
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RE: motor turns
Bear in mind also that there are brushed and brushless motor types. Brushed motors are roughly twice as fast per turn (but provide nowhere near as much torque) as brushless, so when you see a 7 turn double brushed, it is theoretically equivalent to a 3.5 turn 2 pole brushless. But, don't misunderstand me and think that I'm saying brushed are faster, they most certainly are not. Brushless are far superior, except for specific applications (usually low speed, where smoothness is required (brushed are very smooth) such as crawling and drifting) making more speed and torque than brushed per watt.
As for drawbacks...The more turns, the more power it uses (the less your battery will last), and the less torque it has. In general in most applications, it's better to use, say, a 6.5t brushless motor and use gearing to get the speed you need, than to buy a very hot 3.5t motor and be forced to lower the gearing because it's getting hot. That's the other disadvantage. Heat. Heat is always the enemy. Brushless motors should not exceed 190*F or the resin holding the internals together starts to degrade. A very low turn motor (in other words, the very fast motors, 4 turn and less), unless geared absolutely perfectly for the battery and application, will get very hot very quickly. This is another reason people use lower turn motors and taller gearing to achieve the speed they need.
More important to understand is the meaning of KV in relation to brushless motors. You will see most brushless motors have a kv rating. This is the amount of revolutions per minute (rpm) that the motor will turn for every volt you feed it. So let's say you have a 5000kv motor, and you are using a 7.4v lipo battery...that means the motor can turn maximum (7.4x5000) 37000rpm. If I go up to an 11.1v battery (making sure the motor and speed controller can handle it), the theoretical maximum speed goes up to (11.1x5000) 55500. Of course I could achieve the same speed with a 7500kv motor on a 7.4v battery (7.4*7500=55500), but the 7500 motor will use more power and get hotter. See how it works? If you need anything clarified further, let me know.
As for drawbacks...The more turns, the more power it uses (the less your battery will last), and the less torque it has. In general in most applications, it's better to use, say, a 6.5t brushless motor and use gearing to get the speed you need, than to buy a very hot 3.5t motor and be forced to lower the gearing because it's getting hot. That's the other disadvantage. Heat. Heat is always the enemy. Brushless motors should not exceed 190*F or the resin holding the internals together starts to degrade. A very low turn motor (in other words, the very fast motors, 4 turn and less), unless geared absolutely perfectly for the battery and application, will get very hot very quickly. This is another reason people use lower turn motors and taller gearing to achieve the speed they need.
More important to understand is the meaning of KV in relation to brushless motors. You will see most brushless motors have a kv rating. This is the amount of revolutions per minute (rpm) that the motor will turn for every volt you feed it. So let's say you have a 5000kv motor, and you are using a 7.4v lipo battery...that means the motor can turn maximum (7.4x5000) 37000rpm. If I go up to an 11.1v battery (making sure the motor and speed controller can handle it), the theoretical maximum speed goes up to (11.1x5000) 55500. Of course I could achieve the same speed with a 7500kv motor on a 7.4v battery (7.4*7500=55500), but the 7500 motor will use more power and get hotter. See how it works? If you need anything clarified further, let me know.
