# What it parameter "total number of turns in the slot" ns in design BLDC motor?

Hi.

In BLDC motor, what it parameter total number of turns in the slot ns, which enters in the formula of torque?  If Ns is the number of engine slots, then what is then ns?

Does anyone know more details about what that parameter actually represents in engine and what it depends on?

If I want to find, for example, torque, how do I know the value mentioned, is it taken from a table or is it somehow calculated by the formula based on the Ns parameter.

Nomenclature for formulas

Thanks.  Nomenclature.pdf (138 KB)

Aleksandari:
If Ns is the number of engine slots, then what is then ns?

Looks like you did not read the PDF that you gave a link to. It clearly says

ns - Total number of turns in a slot

...R

know what it is (what it's called), but how it is calculated, I don't have that formula, just whether it's somehow calculate or take out of some a table, otherwise I know it's called "total number of turns in the slot" ?

If I want to find, for example, torque, how do I know the value mentioned, is it taken from a table or is it somehow calculated by the formula based on the Ns parameter.

Only that.

Aleksandari:
know what it is (what it's called), but how it is calculated,

You can't calculate the number of turns of wire - you have to count them, or get the number from the manufacturer.

...R

But I'm trying to make BLDC it myself.

Aleksandari:
But I'm trying to make BLDC it myself.

Then you can count the turns of wire as you make the motor.

...R

In any motor the number of turns can be varied in inverse proportion to the current without changing the motor's behaviour mechanically.

The number of turns is relevant only to the voltage rating of the motor. Double the turns of a 12V motor (using wire of half the cross-sectional area), and you have a 24V motor that does the same job.

So I would first start by judging a safe total amp-turns for the slot based on its geometry and the resistivity of copper.

If you can calculate the motor torque constant (in Nm per amp), this is the same as the voltage constant (in volts per rad/s)