Answer simple. DC brush motor and controller is cheaper choice.
Brushless servo motor expensive, DC brush motor cheap.
Brushless servo motor's power stage need 6 transistor and predriver, DCbrush motor need 4 transistor and predriver.
Brushless servo motor need 3 pwm, DC brush motor need only 1 pwm.
AC servo (2 phase) motor is out of fashion.
Usualy stepper motor cheaper then brush type servo motor but
there are problem at the high speeds and high torques. |