Solved Motor kV - The real meaning?

[Hai-Lee]

I love to design, build and fly fixed wing RC model aircraft and as a sort of hobby I also like to investigate the REAL reasons for the crashes on models we experience at our local club.

A trend seemed to appear that made me question the kV rating system as we are informed it is by the manufacturers of the electric motors that we use.
From the crash statistics it appeared that the higher the kV rating of the motor the greater its chance of meeting a sudden end. At first I thought that this must be due to the size of the planes concerned but then when I add the EDF crashes, (some of which where large models), the whole thing just didn't add up!

After a few drinks, (well a few more after an initial few), the whole problem solution became clear. The kV rating may be supposed to mean the thousands of revolutions per volt of applied power but there is a more sinister and statistically proven definition.

WHY, OH WHY didn't I see it before?

Simply put the kV number is actually the motors "kamikaze Value"..

Now that the problem is identified I can relax and have another drink!



Have fun!

 

[DamoRC]

Technically it should be Kamikaze value - the motor kamikaze constant which is the number of kamikazes it takes to make one value, often mistaken with the number of kamikazes you get out if you apply one value.

 

[ElectriSean]

After a few drinks, (well a few more after an initial few), the whole problem solution became clear. The kV rating may be supposed to mean the thousands of revolutions per volt of applied power but there is a more sinister and statistically proven definition.

WHY, OH WHY didn't I see it before?

Simply put the kV number is actually the motors "kamikaze Value"..

Technically Kv is the amount of BEMF generated by the motor, as AC motor speed is dependant on frequency not voltage. But I like your interpretation better