motor turns and kv

[idaho]

Can someone please explain to me what the turns and kv ratings on motors mean?

[Meatwad]

Kv stands for "rpm per volt". The turns can be arbitrary and vary from each manufacturer.

[Sabaot]

As far as I know it goes as follow:

TURNS
This a refference to the number of times the wire is wrapped around a rotor pole. This is described as "T", eg. 12T, 21.5T.

The more turns (higher T) means LESS rpm, MORE torque
The less turns (lower T) means opposite: MORE rpm, LESS torque

In other words 12T motor is faster but weaker, 21.5T motor is slower but more powerful.

KV
As already mentioned - "revolves per minute per volt" - rpm per volt.

It means how fast a motor can rotate with a given voltage input.

Example.
We have a 2000kv motor, it means it can spin 2000 revolves per 1v. Plug that motor to 7.4V battery and you will get max 14,800 rpm (2000 * 7.4).

Now, same motor but 11.1V battery will result in max 22,200.

Hope that helps.

Cheers.

[Calderwood]

Originally Posted by Meatwad

Kv stands for "rpm per volt". The turns can be arbitrary and vary from each manufacturer.

Arbitrary when discussing brushless motors but for brushed motors its what saboat describes above.

Brushed motors:

[Charlie-III]

Originally Posted by nigels_world

Arbitrary when discussing brushless motors but for brushed motors its what saboat describes above.

Brushed motors:

+1.....

Turns (T) in a brushed motor are the number of wire turns/pole.

"Turns" (T) in a brushless motor are sorta arbitrary, but "KV" is a "little" more specific for brushless motors.

There is no real "good" comparison between brushed turns and brushless "T" or KV.

Basically (as stated) low "T" in brushed is high RPM / low torque. High "T" in brushed is low in RPM / high torque.

In brushless, low KV = low speed / high torque, high KV = high speed / low torque.
The brushless "T" ratng is trying to equate to a brushed turn rating.
Brushed does not have "1/2 turns", only full turns.
You won't see a 12.5T brushed motor, but can find 12.5T brushless motors.

[Meatwad]

Originally Posted by nigels_world

Arbitrary when discussing brushless motors but for brushed motors its what saboat describes above.

Very much a truism, my post assumed brushless specific for some reason. Motor turns in brushed motors refer specifically to the physical amount of wire, whereas brushless motors it seems arbitrary.

[supermoturd]

So, does the turn count determine how smoothly the motor turns? I ask because in a crawler, I want nice, smooth (not jerky) rotation at slow speeds. On a related note, how much of a role does the throttle response on the radio and the resolution of the ESC play in smooth acceleration?

[6sharky9]

You have sensored and non sensored motors and Speed controllers

Non sensored wlll give you a lot of speed but doesn't start out as smooth down low and aren't really a good choice for rock crawling or trail use.

Sensored set up are a little smoother down low but still does not equal that of a quality brushed motor for crawling.

More common equivalents between brushed and brushless are as follows:

13.5T brushless is said to be the same as a 27T brushed motor.
10.5T = a 19T brushed.

If you want a brushless for crawling get a sensored set up and gear it down more than you would a brushed motor to get closer to brushed control and torque.

Common crawling turns for brushless are 17.5 and 21.5

I prefer brushed though as brushless hasn't quite caught up on the lower rpms just yet with out a more powerful battery and steeper gearing but it seems to be the latest FAD to want brushless..Brushed is more controllable for crawling..But if you want acceptable torque with a little less control and a lot more speed than go brushless.

[supermoturd]

Originally Posted by 6sharky9

You have sensored and non sensored motors and Speed controllers

Non sensored wlll give you a lot of speed but doesn't start out as smooth down low and aren't really a good choice for rock crawling or trail use.

Sensored set up are a little smoother down low but still does not equal that of a quality brushed motor for crawling.

More common equivalents between brushed and brushless are as follows:

13.5T brushless is said to be the same as a 27T brushed motor.
10.5T = a 19T brushed.

If you want a brushless for crawling get a sensored set up and gear it down more than you would a brushed motor to get closer to brushed control and torque.

Thanks, Sharky. That is useful information.

[6sharky9]

Youre welcome