Examples include a method for controlling a synchronous motor using a variable speed drive. The motor includes a permanent magnet rotor generating a magnetic flux. The method includes applying a predefined electrical command signal to the motor and estimating a motor speed in response to the applying of the predefined electrical command signal. The method also includes reaching a desired estimated motor speed and, in response to reaching the desired estimated motor speed, estimating a parameter related to the magnetic flux of the permanent magnet rotor. The method further includes recording the estimated parameter.

Examples include a method for controlling a synchronous motor using a variable speed drive. The motor includes a permanent magnet rotor generating a magnetic flux. The method includes applying a predefined electrical command signal to the motor and estimating a motor speed in response to the applying of the predefined electrical command signal. The method also includes reaching a desired estimated motor speed and, in response to reaching the desired estimated motor speed, estimating a parameter related to the magnetic flux of the permanent magnet rotor. The method further includes recording the estimated parameter.

A method and system to convert a constant speed motor drive (40) into a variable speed motor drive (80) are disclosed. The method comprises disconnecting a second terminal (68) from a first terminal (54) by removing from the constant speed motor drive (40) a first cover assembly (46) comprising the second terminal (68), the constant speed motor drive (40) comprising the first cover assembly (46) and a base assembly (42) including the first terminal (54), the cover assembly further comprising a constant speed controller (66), the first terminal (54) adapted to receive an alternating-current (AC) voltage and including motor contacts operable to output a motor voltage, wherein the constant speed controller (66) generates the motor voltage for the motor contacts when the constant speed controller (66) operates; and connecting a third terminal (68) to the first terminal (54) by coupling a second cover assembly (82) to the base assembly (42), the second cover assembly (82) comprising the third terminal (68) and a variable speed controller (100) electrically coupled to the third terminal (68).

A method and system to convert a constant speed motor drive (40) into a variable speed motor drive (80) are disclosed. The method comprises disconnecting a second terminal (68) from a first terminal (54) by removing from the constant speed motor drive (40) a first cover assembly (46) comprising the second terminal (68), the constant speed motor drive (40) comprising the first cover assembly (46) and a base assembly (42) including the first terminal (54), the cover assembly further comprising a constant speed controller (66), the first terminal (54) adapted to receive an alternating-current (AC) voltage and including motor contacts operable to output a motor voltage, wherein the constant speed controller (66) generates the motor voltage for the motor contacts when the constant speed controller (66) operates; and connecting a third terminal (68) to the first terminal (54) by coupling a second cover assembly (82) to the base assembly (42), the second cover assembly (82) comprising the third terminal (68) and a variable speed controller (100) electrically coupled to the third terminal (68).

A method and system to convert a constant speed motor drive (40) into a variable speed motor drive (80) are disclosed. The method comprises disconnecting a second terminal (68) from a first terminal (54) by removing from the constant speed motor drive (40) a first cover assembly (46) comprising the second terminal (68), the constant speed motor drive (40) comprising the first cover assembly (46) and a base assembly (42) including the first terminal (54), the cover assembly further comprising a constant speed controller (66), the first terminal (54) adapted to receive an alternating-current (AC) voltage and including motor contacts operable to output a motor voltage, wherein the constant speed controller (66) generates the motor voltage for the motor contacts when the constant speed controller (66) operates; and connecting a third terminal (68) to the first terminal (54) by coupling a second cover assembly (82) to the base assembly (42), the second cover assembly (82) comprising the third terminal (68) and a variable speed controller (100) electrically coupled to the third terminal (68).

A method and system to convert a constant speed motor drive (40) into a variable speed motor drive (80) are disclosed. The method comprises disconnecting a second terminal (68) from a first terminal (54) by removing from the constant speed motor drive (40) a first cover assembly (46) comprising the second terminal (68), the constant speed motor drive (40) comprising the first cover assembly (46) and a base assembly (42) including the first terminal (54), the cover assembly further comprising a constant speed controller (66), the first terminal (54) adapted to receive an alternating-current (AC) voltage and including motor contacts operable to output a motor voltage, wherein the constant speed controller (66) generates the motor voltage for the motor contacts when the constant speed controller (66) operates; and connecting a third terminal (68) to the first terminal (54) by coupling a second cover assembly (82) to the base assembly (42), the second cover assembly (82) comprising the third terminal (68) and a variable speed controller (100) electrically coupled to the third terminal (68).