Confusion in block diagram of open loop and close loop control system?
This system:



Actually uses the Motor's back EMF as a feedback signal, it does not use the speed information directly.

From a back EMF viewpoint, this is a closed system (the back EMF is directly controlled).

From a motor speed viewpoint, this is an open system (the speed is not directly controlled).

However, this system:



does use the speed of the motor as a feedback signal so the speed is directly controlled.

There is still the back EMF feedback but that does not control the motor speed directly (assuming "sane" choices for \$K_b\$ and \$K_t\$)