Motot constant
Found this at http://en.wikipedia.org/w/index.php?title=Brushless_DC_electric_motor&diff;=483432978&oldid;=483432770

== KM rating ==
''KM'' is the ''motor constant'' (sometimes, ''motor size constant''), defined as:
:\frac{\tau}{\sqrt{P}}

where
* \scriptstyle \tau is the motor torque (SI units, N·m)
* \scriptstyle P is the resistive power loss (SI units, W)

The motor constant is winding independent (as long as the same conductive material used for wires); e.g., winding a motor with 6 turns with 2 parallel wires instead of 12 turns single wire will double the velocity constant, Kv, but KM remains unchanged.  KM can be used for selecting the size of a motor to use in an application.  Kv can be used for selecting the winding to use in the motor./

It look to me as if the scope is well beyond the original article and if put anywhere - it should be herer.