# Motor constant

## Description

The constant K_M (motor size constant) is a value used to describe characteristics of electrical motors.

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.

Related formulas## Variables

K_{M} | motor constant (N*m/sqrt(Watt)) (dimensionless) |

τ | motor torque (N*m) (dimensionless) |

P | resistive power loss (Watt) (dimensionless) |