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Analyzing electric motors

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Old 09-16-2011, 08:00 PM
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Meafordguy
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Default Analyzing electric motors

So many motors, so little knowledge. Can someone please explain the two main stats I see when looking at electric motors for RC Trucks.

Already understand the difference between brushed and brushless.


First is KV such as a 3200kv .... Does more kv mean more power?

A number such as 540 indicates the size of the motor? Important to know that it wil fit into your car.

Second is Turns.. Is this like rpms? What is the difference between higher and lower turns? Why is that important to know?

How do you know what esc to get with a motor? How do you know if your esc will work with a motor that you order?

For example, when reading this page, how do I know the difference between the motors for 1/10 RC cars and trucks?
http://www.hobbypartz.com/gensacesale.html


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Old 09-16-2011, 08:26 PM
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Default RE: Analyzing electric motors

KVis the number of rpms the motor will theoretically spin per volt of input.
The number of turns relates to using a thicker wire with less turns which makes less low speed torque but higher rpm.
rock crawlers typically use a high number of turns while all out racers use a few turns. For example a rock crawler with a brushed motor will typically use a 35 to 55 turn motor while a touring car may use a 19 turn.
The most common number of turns for brushed motors was 27 turns which gave decent all around performance.
Ibelieve brushless motors can get away with a lot less turns on average but Iam somewhat new to them myself.
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Old 09-16-2011, 08:34 PM
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Default RE: Analyzing electric motors

Do you think it is number of rpms per volt, per second = Kv?
One way I could look at it is like a gear ratio. Fewer turns would be a higher gear, like on a bicycle in top gear, you peddle slower but
your top speed will be higher. And same thing vice versa with low gears.
If you want a rock crawler or rough terrain truck with big tires, you want more torque, less top speed, so you would want a motor with
Higher number of turns. Street racer, lower turns (higher gear)
Anyone else want to elaborate on some of the other questions please do!
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Old 09-17-2011, 05:01 AM
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Default RE: Analyzing electric motors

Actually I found this cool video which helps to explain a lot.

[youtube]http://www.youtube.com/watch?v=HSKXK...layer_embedded[/youtube]
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