Patent ID: 7412339

Claim:
A method for identifying an operational phase of a motor, the method comprising: obtaining a first value of a signal that is indicative of the operational phase of the motor; obtaining a second value of the signal after a first time period has expired; obtaining a third value of the signal after a second time period has expired; obtaining a fourth value of the signal after a third time period has expired; determining a first change identifying a change between the first and third values with time; determining a second change identifying a change between the second and fourth values with time; identifying a first operational phase of the motor for the first change exceeding a first threshold value by more than a non-negative first predetermined value and the second change exceeding a second threshold value by more than a non-negative second predetermined value; identifying a second operational phase of the motor for the first change not exceeding the first threshold value, the second change not exceeding the second threshold value, the first change not exceeding a non-positive third predetermined value, and the second change not exceeding a non-positive fourth predetermined value; and operating the motor in accordance with the identified operational phase.