Motor velocity control servo amplifier

A sampling servo amplifier for controlling the velocity of a motor having at least one motor winding, comprising in combination:

• first means connected to a winding of the motor and generating a motor velocity signal varying with the motor back emf, said first means including means for storing the motor velocity signal during a motor sample time interval, and further including first switching means for connecting the motor velocity signal to said means for storing in response to a timing signal during the motor sample time interval,
• means for combining the motor velocity signal and a motor command signal into a motor drive voltage,
• an amplifier responsive to the motor drive signal for generating a voltage during the motor drive time having an amplitude varying with the amplitude of the motor drive signal,
• a first power amplifier connected to a first voltage for energizing the motor to rotate in a first direction,
• a first switch actuated by the motor drive signal of said amplifier of a first sense during the motor drive time to turn on said first power amplifier to connect the first voltage to the motor,
• a second power amplifier connected to a second voltage for energizing the motor to rotate in a second direction,
• a second switch actuated by the motor drive signal of said amplifier of a second sense during the motor drive time to turn on said second power amplifier to connect the second voltage to the motor,
• second switching means for interrupting the application of the output voltage of said amplifier to said first and second switches during the motor sample time interval and for connecting the output of said amplifier to said switches in response to the timing signal during the motor drive time, and
• means for generating the timing signal to said first means for switching and to said second means for switching.