The essence of 32mm57mm and 36mm57mm planetary DC gear motors is a combination of high‑speed miniature permanent‑magnet DC motors and planetary gearbox.
The character of DC motor itself is high rotational speed but low torque which has poor load-carrying capacity and can not drive heavy structural subject.
In order to let it have low speed and high torque,so we it is equipped with a planetary reduction gearbox which makes the speed is reduced and the output torque is becoming bigger which is the advantage of 32mm57mm/36mm57mm planetary DC gear motor.
As the planetary gearbox’s structure is a fixed reduction ratio , so it only has some basic rotate speed.If let it have contimuous stepless speed regulation and the speed can be adjusted freely, a PWM electronic speed controller is generally equipped.
Most 3257 and 3657 miniature planetary DC gear motors adopt permanent-magnet DC structures and do not have external excitation whose speed is regulated simply by controlling the armature voltage,and in such miniature gear motors they are rarely used while separately excited .
In terms of speed detection, the actual speed of these DC gear motors cannot be accurately measured via current’s feedback. In practical applications, Hall sensors or Back-EMF detection are commonly used to estimate the rotational speed