Patent ID: 7940022

Claim:
A motor controlling device, comprising: a first sensor for detecting a switching phase signal generated by a motor and obtaining a first switching phase signal corresponding to the switching phase signal; a second sensor for detecting the switching phase signal generated by the motor and obtaining a second switching phase signal corresponding to the switching phase signal; and a signal switching circuit electrically connected to the first sensor and the second sensor, respectively, wherein the signal switching circuit comprises: a measuring component for measuring after the motor has been started and having a predetermined value, wherein the measuring component outputs a switching signal when an actual value is measured and the measured actual value reaches to the predetermined value; and a switch component electrically connected to the measuring component, wherein the switch component is switched from the first sensor to the second sensor after the switch component receives the switching signal, wherein the signal switching circuit is switched to the first sensor for outputting the first switching phase signal when the motor starts to operate, and the signal switching circuit is switched to the second sensor for outputting the second switching phase signal when a predetermined switching condition is satisfied during the motor operation.