Inside most electrical motors there is a switch called a rotary switch. This switch acts like the automatic gear transmission in our cars. First lets understand that a electrical motor when initially stared from a stationery mode will have a harder time to push start whatever the motor is driving. Similarly, when we start our cars, we engage a low gear first so the car has more power to push run itself. It is only after it has run smoothly that we change to higher gear so it won’t be so taxing on the gear system of the car
A basic rotary switch looks like a plate held together with springs holding the electrical terminals together. The fact that is is called a rotary switch is because this switch works depending on the rotation of the switch. If the switch is spun fast enough it will open the switch with the G force build up by the spin.
On the same concept, if the electrical motor is driving some heavy machinery, it need the starting power to get that machinery moving. To achieve that, the coils inside the motor are bind-ed in such a way that it works like a car’s gear system. This is where the rotary switch comes into play. The first layer of coils inside the motor is like the first low gear of our car. The rotary switch is the device connected to that coil and back to the switch starter panel.
During the starting phase of the motor when it needs the most power, the first layer of coil contributes to the rest by push starting the motor. Slowly speed build up and when it reaches a certain speed, the contacts of the rotary switch swings open due to the sheer G force of the spin. When that happens, the first layer coils is cut off and the motor will running smoothly.
