When the speed sensor is integrated into the application
equipment, the mechanical structure would become more
complex and the manufacturing cost of equipment would be
increased as well. The testing efficiency must become worse
because much more time will be required to change the speed
sensor;If the allowed installing space of the real speed sensor
has been critical limited, the direct speed measuring method
may be not suitable to be used here;When the direct speed
measuring method is applied to the measurement of torquespeed
characteristic curve for the measured DC motor, much
more time may be taken for adjusting the different load
condition.