Why is it that the motor of the drill has a buzz when it touches the switch lightly? It is not like the sound made by the mechanical structure. Is it the sound of the current?
The first step is to start with the starting principle of the motor. When the motor starts, there is a response time. Not to say that a power supply begins to rotate immediately. When the motor is not reached before starting speed, which transform magnetic field between the rotor and the stator of the motor, the magnetic field will transform energy if the energy is not driven from the rotor starts to rotate would be released by another, or fever, or noise, or magnetic leakage. Generally, what we can intuitively understand is sound and heat.
Many electric drills are operated at low speed, and the speed of the turn is slow. When the touch switch is switched on, the power of the drill can not be reached, so the sound that you hear is the sound of this vibration.
The electric current itself is silent, and only when the current passes through the conductor is subjected to electromagnetic force can the sound vibrate
Many electric drills are adjustable speedThe touch switch, an electric drill through the thyristor voltage, non sinusoidal voltage supply electric drill is very low, this time is not enough torque rotating drill, so a tiny vibration, the sound you hear is the sound vibration
