Control system for an electronically commutated motor, method of controlling such, method of controlling an electronically commutated motor and laundry apparatus

A method for controlling a system having an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:

• digitizing the voltages across the winding stages;
• generating successive patterns of the control signals for the commutating means in response to successive patterns of digital signals;
• prestoring data representing at least one preselected sequence of the patterns of the digital signals and prestoring data, corresponding to each pattern of the digital signals, identifying the respective digitized voltage for the at least one unpowered winding stage;
• successively producing one of the patterns of the digital signals and sensing only the identified digitized voltage corresponding to the one pattern;
• and
• producing the following pattern in sequence after at least one predetermined logic level of the identified digitized voltage has occurred.

A method for controlling a system having an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, first and second conductors for supplying power, and means for commutating the winding stages and producing a current in the winding stages by selectively switching the winding stages to the supply conductors in response to a pattern of control signals, the method comprising the steps of:

• producing successive patterns of digital signals in at least one preselected sequence;
• generating patterns of the control signals for the commutating means in response to the successive patterns of the digital signals;
• comparing the current in the winding stages of the electronically commutated motor with a predetermined level;
• and
• producing a preestablished pattern of the digital signals for a predetermined period of time to reduce the current in the winding stages, whenever the predetermined level is exceeded and periodically producing the current reducing pattern of the digital signals at an adjustable rate when the predetermined level is not exceeded.

A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, first and second conductors for supplying power, and means for commutating the winding stages and producing a current in the winding stages by selectively switching the winding stages to the supply conductors in response to a pattern of control signals, the control circuit comprising:

• means for generating patterns of the control signals for the commutating means in response to successive patterns of digital signals;
• means for comparing the current in the winding stages of the electronically commutated motor with a predetermined level;
• and
• means for producing the successive patterns of digital signals in at least one preselected sequence for said generating means, for producing in response to said comparing means a preestablished pattern of the digital signals to reduce the current in the winding stages upon the predetermined level being exceeded, for monitoring the voltage across the winding stages to monitor the position of the rotatable means when the current is being reduced, and for resuming producing the successive patterns of digital signals in sequence after a predetermined time interval.

A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, the control system comprising:

• means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered;
• means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means;
• and
• means for producing the successive patterns of the digital signals in at least one preselected sequence, and for subsequently producing a different pattern of the digital signals which causes said commutating means to connect all of the winding stages together, thereby braking the motor.

A method for controlling an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:

• producing successive patterns of the control signals in at least one preselected sequence of commutating the winding stages in a first connection arrangement;
• producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered;
• switching the winding stages to a second connection arrangement;
• sensing the position of the rotating means from the winding stages while they are temporarily unpowered;
• and
• resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the position of the rotating means sensed while the winding stages are temporarily unpowered.

A method for controlling an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:

• converting the voltages across the winding stages to digital form thereby to digitize the voltages;
• producing successive patterns of the control signals in at least one preselected sequence to commutate the winding stages and rotate the rotatable means;
• subsequently producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered;
• sensing the digitized voltages while the winding stages are temporarily unpowered;
• determining a pattern of the control signals from the sensed digitized voltages;
• and
• resuming producing the successive patterns of the control signals in sequence beginning with the pattern so determined.

A method for controlling an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:

• generating successive patterns of the control signals for the commutating means in response to successive patterns of digital signals;
• producing the successive patterns of the digital signals in at least one preselected sequence;
• and
• producing a different pattern of the digital signals which causes the commutating means to connect all of the winding stages together, thereby braking the motor.

A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and first and second conductors for supplying power, the control system comprising:

• means for commutating the winding stages in response to successive patterns of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, said commutating means including sets of electronic devices connected across the supply conductors, each set having a junction point connected to a respective one of the winding stages, each of said electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals;
• and
• means for producing the successive patterns of the control signals in at least one preselected sequence to switch on only one electronic device in each of at least two of the sets of said electronic devices at once and cause a current to flow in the winding stages to rotate the rotatable means, and for subsequently producing a pattern of the control signals to switch off one of said electronic switching devices which was previously switched on so that said commutating means leaves all of the winding stages temporarily unpowered and also provides a current path for the previously-powered winding stages, said control signal producing means comprising means responsive to successive patterns of digital signals for generating the successive patterns of the control signals for said commutating means, said generating means including first and second logic gate means feeding said sets of electronic devices in said commutating means and having inputs driven by respective pairs of digital signals in the digital signal patterns, means for disabling said first and second logic gate means when any of the pairs of digital signals has identical logic levels in the pair, and means for disabling in response to a disabling signal a single one of said first and second logic gate means identified by an additional pair of digital signals in the digital signal patterns.

A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the control system comprising:

• means coupled to the winding stages for simultaneously converting the voltages across the winding stages to digital form thereby to digitize the voltages;
• means responsive to successive patterns of digital signals for generating successive patterns of the control signals for the commutating means;
• and
• means for producing successive patterns of the digital signals in a first preselected sequence, producing a different pattern of the digital signals for causing the commutating means to remove power from all of the winding stages, sensing the digitized voltages while the power is so removed, and producing successive patterns of the digital signals in a second preselected sequence to rotate the rotatable means in the reverse direction after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
• means coupled to said winding stages for simultaneously converting voltages across said winding stages to digital form thereby to digitize the voltages;
• means for producing successive patterns of digital signals in at least one preselected sequence, for selecting the digitized voltage across said at least one unpowered winding stage depending on the digital signal pattern produced, and for producing a following pattern in sequence after at least one predetermined logic level of the selected digitized voltage has occurred;
• and
• means responsive to the successive patterns of the digital signals for generating the successive patterns of the control signals for said commutating means.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages and producing a current in said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
• means for producing successive patterns of digital signals in at least one preselected sequence;
• means for generating patterns of the control signals for said commutating means in response to the successive patterns of the digital signals;
• and
• means for comparing the current in said winding stages of said electronically commutated motor with an electrical level representative of a predetermined current,
• said pattern producing means including means for also producing a preestablished pattern of the digital signals for a predetermined period of time to reduce the current in said winding stages whenever the predetermined level is exceeded, and periodically producing the current reducing pattern of the digital signals at an adjustable rate when the predetermined level is not exceeded.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages and producing a current in said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
• means for generating patterns of the control signals for said commutation means in response to successive patterns of digital signals;
• means for comparing the current in said winding stages of said electronically commutated motor with a predetermined level;
• and
• means for producing the successive patterns of digital signals in at least one preselected sequence for said generating means, for producing in response to said comparing means a preestablished pattern of the digital signals to reduce the current in said winding stages upon the predetermined level being exceeded, for monitoring voltages across said winding stages to monitor the position of said rotatable means when the current is being reduced, and for resuming producing the successive patterns of digital signals in sequence after a predetermined time interval.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
• means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
• and
• means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, for subsequently producing a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered, for sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
• means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means;
• and
• means for producing the successive patterns of the digital signals in at least one preselected sequence, and for subsequently producing a different pattern of the digital signals which causes said commutating means to connect all of said winding stages together, thereby braking said motor.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to successive patterns of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered, said commutating means including sets of electronic devices connected across said supply conductors, each set having a junction point connected to a respective one of said winding stages, each of said electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals;
• and
• means for producing the successive patterns of the control signals in at least one preselected sequence to switch on only one electronic device in each of at least two of said sets of said electronic devices at once and cause a current to flow in said winding stages to rotate said rotatable means, and for subsequently producing a pattern of the control signals to switch off one of said electronic switching devices which was previously switched on so that said commutating means leaves all of said winding stages temporarily unpowered and also provides a current path for the previously-powered winding stages.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
• means coupled to said winding stages for simultaneously converting voltages across said winding stages to digital form thereby to digitize the voltages;
• means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means;
• and
• means for producing successive patterns of the digital signals in a first preselected sequence, producing a different pattern of the digital signals for causing said commutating means to remove power from all of said winding stages, sensing the digitized voltages while the power is so removed, and producing successive patterns of the digital signals in a second preselected sequence to rotate said rotatable means in the reverse direction after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
• means coupled to said winding stages for digitizing the voltages across said winding stages;
• means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means;
• and
• a digital computer operating under stored program control, said computer having inputs for the digitized voltages, said computer having memory elements for storing data representing at least one preselected sequence of the patterns of the digital signals and for storing data, corresponding to each pattern of the digital signals, identifying the respective input for the digitized voltage for said at least one unpowered winding stage, said computer successively producing one of the patterns of the digital signals, sensing only the digitized voltage at the identified input corresponding to the one pattern and producing the following pattern in sequence as soon as complementary logic levels of the digitized voltage at the identified input have occurred in a predetermined order if they so occur within a predetermined time period and otherwise producing the following pattern in sequence after the predetermined time period.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered, said commutating means including sets of electronic devices connected across said supply conductors, each set having a junction point connected to a respective one of said winding stages, each of said electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals;
• means coupled to said winding stages for digitizing voltages across said winding stages;
• means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means, including first and second logic gate means feeding said commutating means and having inputs driven by respective pairs of digital signals in the digital signal patterns, means for disabling said first and second logic gate means when any of the pairs of digital signals has identical logic levels in the pair, and means for disabling one of said first and second logic gate means in response to a signal to cause the current in said other powered winding stages to be reduced;
• a digital computer operating under stored program control, said computer having inputs for the digitized voltages, said computer having memory elements for storing data representing at least one preselected sequence of the patterns of the digital signals and for storing data, corresponding to each pattern of the digital signals, identifying the respective input for the digitized voltage for said at least one unpowered winding stage, said computer successively producing one of the patterns of the digital signals, sensing only the digitized voltage at the identified input corresponding to the one pattern and producing the following pattern in sequence after at least one predetermined logic level of the digitized voltage at the identified input has occurred;
• and
• means for comparing currents flowing in said winding stages of said electronically commutated motor with an electrical level representative of a predetermined current, and upon the level being exceeded, interrupting said digital computer and supplying the signal to said disabling means, said digital computer also having memory locations for storing data identifying one of said first and second conductors corresponding to each pattern of the digital signals, said digital computer including means for causing said disabling means to disable switching by said electronic devices to said one identified conductor corresponding to the pattern of the digital signals which is being produced when the interrupting occurs.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
• means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
• means for selecting the laundering mode and the spin mode;
• means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement, wherein one of the first and second connection arrangements is a low speed connection arrangement and the other of the first and second connection arrangements is a higher speed connection arrangement;
• and
• means coupled to said selecting means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, for also counting revolutions of said rotatable means in the laundering mode by counting the successive patterns of control signals produced and, when the counting reaches a predetermined value, causing said rotatable means to reverse by also producing a pattern of the control signals which causes said commutating means to switch all of said winding stages to one of said supply conductors and then producing the patterns of control signals in a second preselected sequence, and for subsequently producing in the spin mode a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, for sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the second digitized voltages.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
• means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
• means for selecting the laundering mode and the spin mode;
• means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement, wherein one of the first and second connection arrangements is a low speed connection arrangement and the other of the first and second conection arrangements is a higher speed connection arrangement;
• and
• means coupled to said selecting means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, for also counting revolutions of said rotatable means in the laundering mode by counting the successive patterns of control signals produced and, when the counting reaches a predetermined value, producing a pattern of the control signals for causing said commutating means to remove power from all of said winding stages, sensing the digitized voltages while the power is so removed, and producing successive patterns of the control signals in a second preselected sequence to rotate said rotatable means in the reverse direction only after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages, and for subsequently producing in the spin mode a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, for sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
• means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
• means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement;
• and
• means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, the successive patterns of the control signals being identified by values of an index, for subsequently producing a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, for repetitively sensing the digitized voltages while said winding stages are temporarily unpowered, determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages as soon as a change occurs in any one of the sensed digitized voltages, and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals identified by the value of the index so determined.

Laundry apparatus comprising:

• means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
• an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
• first and second conductors for supplying power;
• means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
• means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages, said converting means including means for generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each winding stage comprising the logic levels so generated;
• means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement;
• and
• means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, selecting the digitized voltage across the at least one unpowered winding stage depending on each of the successive patterns produced, producing a following pattern in sequence after complementary logic levels of the selected digitized voltage have occurred in a predetermined order if they so occur within a predetermined time period and otherwise producing the following pattern in sequence after the predetermined time period, and subsequently producing a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.