Brushless motor the back emf constant KE is to have cultured, because here include the counter electromotive force of the motor constant KE KE and generator of induction electromotive force constants, although they can be thought of as the same value, but the concept is not the same as KE counter electromotive force of the motor constant with the rotational speed of units counter electromotive force, its expression is KE = E/n = U/n’ 0 in the technical requirements of the motor, the motor rated voltage U, motor rated speed of nN is must be some N is the speed of the motor output shaft, can be measured, but E did not express on the shaft of the motor, cannot express in the input motor power, motor coil is a quantity of the internal potential. In the formula, the voltage U is the power input end of a clear input, but the ideal no-load rotation speed of the motor n’ 0 in the shaft end of the motor can't express and measurement, so use formula KE = U/n’ 0 to find the counter electromotive force of the motor constant KE is difficult. How the technical conditions of the brushless motor or mechanical characteristic curve of determining and calculating KE counter electromotive force constant of the motor, the design conforms to the KE parameter values of mechanical characteristic curve of the brushless motor is a need to study the topic if the KE, KE = NΦ Effective conductor / 60, then the motor number N and motor flux & Phi; The product of the (Magnetic chain NΦ ）KE to counter electromotive force of the motor constant values, then the mechanical properties of the motor is basically achieve the desired mechanical properties. Observed here are several counter electromotive force of the motor constant KE method, thus the effective number of conductor N of the motor, finally achieve the aim of brushless motor design.
