What is the electric drill and hammer used in AC motor home decoration are familiar and different electric tools. They are usually matched with series motor drive, with basic control functions such as speed, steering transformation and torque characteristics adjustment, so as to adapt to different task objects.
The question arises, why use series motor drive mode at all? On the one hand, in order to simplify the control mode and minimize the weight of the tool as much as possible, on the other hand, the danger caused by drilling and vibrating cutting tool overload must be eliminated. The external characteristics of the driving motor are relatively soft, that is, when the rated load is exceeded, the motor speed decreases rapidly with the increase of the load.
Ac series motor for AC power supply. The excitation winding and armature winding of this kind of motor form a series circuit through the brush and commutator, which has very unique advantages: it can use AC power supply to work, also can use DC power supply to work; High working speed, small volume, light weight; Smooth speed regulation, wide range, simple and reliable control; When the speed is less than the rated load, the speed is basically constant, and when it exceeds a certain load value, the speed decreases rapidly. Therefore, most electric tools use series motor, simple control, cost-effective, safe and reliable and other excellent characteristics of the series motor in the field of power tools established a firm position.
Series motor's basic structure for the stator and the armature and chassis, the use of specific conditions, such as frequent starting, the vibration of high speed, large, and the working condition of changing load, etc., can lead to motor stalling, and temperature rise of motor stator winding and armature, in practice we can feel the electric tools serious fever. Based on the above reasons, the armature quality and performance of series motor are required very high.
Part of ac series motor rotor, "coil + commutator of the armature, through directly connected to the excitation winding of the stator of carbon brush, so the size of the armature current and exciting current are exactly the same, although the nature of a typical dc motor, but still have difference with common dc motor, the starting torque is bigger, features, soft, Therefore, electric tools are widely used in series motor rather than ordinary DC motor.
