Electric massager circuit

Massage therapy, also known as massage, is one of the medical treatment methods in my country. The traditional method is that the healer uses his hands to
treat certain parts of the human body using 8 techniques including connecting, rubbing, kneading, holding, pulling, tapping, vibrating, and shaking, which can dredge meridians, reconcile qi and blood, calm and relieve pain, and promote
It has functions such as absorption, excitement and refreshing, relieving fatigue, and adjusting body functions. It can treat many diseases and is an effective treatment method in traditional Chinese medicine. Traditional
massage methods are performed manually, which is a form of strenuous physical labor. In order to solve this problem, people developed an electric climbing device.
    Most electric massagers use 220V, 50Hz AC power supply, and their power consumption is not large, 5 to 35W. It has the characteristics of easy use, remarkable effect
and wide clinical adaptability. It is not only widely used in hospital physical therapy departments, but also commonly used in bathrooms, barber shops, sports teams, and homes
.
    The working principle of the electric massager is: when the power is turned on, the motor starts to rotate, and its rotation force drives the eccentric wheel to rotate through the coupling spring.
Since the center of gravity of the eccentric wheel is offset from the axis, an unbalanced and rapid movement occurs when it rotates. shake. The massager is equipped with an appropriate massage head and placed on
the area that needs massage, so that high-speed vibration can achieve an ideal massage effect.
    Electric massagers usually use small brush motors, which have high speed and large torque. It is an AC and DC dual-purpose motor with a speed of about
5000 ~ 1000r/min. Since the massage head is directly affected by the vibration generated by the rotation of the eccentric wheel, the number of massages is the number of revolutions of the motor.
The electric massage device has a setting for adjusting the strength of the massage force. The higher the motor speed, the greater the rocking force generated by the eccentric wheel, and
the stronger the massage force generated by the massage head; conversely, the massage force generated by the massage head is weak. When the input voltage to the motor is high, its speed is high; when the input voltage decreases, the speed
also decreases. Usually, a diode is connected to the circuit, and the connection form of the components in the circuit is changed through different positions of the switch, thereby changing
the voltage input to the motor, thereby changing the speed. The electric massager circuit is shown in Figure 24-7.
    It can be seen from the circuit schematic diagram that when the power switch SB is in the "US" position
, the circuit is disconnected and the motor does not rotate. When switch SB is half-wave rectification,
the input voltage of the motor is low, so the speed is low. When the switch is moved to the strong position
. The alternating current does not undergo half-wave rectification, and the input voltage of the motor is
twice that of half-wave rectification . The voltage is high and the motor speed is the highest. Li,
Lz, and C in the circuit form an anti-interference circuit to prevent sparks generated when the motor 's brushes rub against the commutator from interfering with radios or other electronic equipment.