Laundering machines

Claim 3

A method according to Claim 1 wherein the DC voltage is provided across a pair of DC lines (80, 82) as a full wave rectified sinusoidal signal (100) derived from an AC source, and the method further comprising: converting the full wave rectified sinusoidal signal (100) into voltage pulses (101) having a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal, the first control function being imposed on the operation of the laundry machine by modulating the width of the voltage pulses (101) in accordance with the selected one of the plurality of first waveshapes, and limiting the voltage pulses to a variable time interval in each half cycle of the full wave rectified sinusoidal signal during which the amplitude thereof exceeds the amplitude of the effective voltage.

Claim 4

A method according to Claim 1 wherein the DC voltage is provided across a pair of DC lines (80, 82) as a full wave rectified sinusoidal signal (100) derived from an AC source, and the control circuit has a plurality of current paths each including at least one of the winding stages, the method further comprising: converting the full wave rectified sinusoidal signal (100) into voltage pulses (101) having a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal, the first control function being imposed on the operation of the laundry machine by modulating the width of the voltage pulses (101) in accordance with the selected one of the plurality of first waveshapes; the winding stages being commutated by sequentially allowing the current paths to become conductive; and controlling the conductivity of respective current paths with the voltage pulses when the current paths are sequentially rendered conductive.

Claim 5

A laundering apparatus comprising a laundry machine having at least one rotatable component comprising a tub (10) for receiving the wash load, and characterised in that the at least one rotatable component is coupled to a rotatable assembly (1161) of an electronically commutated DC motor (30), the motor further including a stationary assembly (1161) including a plurality of winding stages (a,b,c) ; and the apparatus further comprising a control system connected to the motor and comprising first control means including means (132) for providing a plurality of first waveshapes, means (138,140) for selecting one of the first waveshapes, and means (72) for controlling the application of a DC voltage in accordance with the selected first waveshape adapted to provide a resultant effective voltage (V M ) to said winding stages (a,b,c); second control means including means (166) for selectively setting the maximum amplitude of the effective voltage through said first control means; and means (74, 76) for commutating said winding stages by applying the effective voltage thereto in sequence; whereby said first and second control means jointly determine the angular velocity of said rotatable assembly and said at least one rotatable component selectively coupled thereto.

Claim 6

A laundering apparatus comprising a laundry machine having at least one rotatable component comprising a tub (10) for receiving the wash load, and characterised in that the at least one rotatable component is coupled to a rotatable assembly (1161) of an electronically commutated DC motor (30), the motor further including a stationary assembly (1161) including a plurality of winding stages (a,b,c) ; and the apparatus further comprising a control system connected to the motor and comprising first control means including means (132) for providing a plurality of first waveshapes, means (138,140) for selecting one of the first waveshapes, and means (72) for controlling the application of a DC voltage in accordance with the selected first waveshape adapted to provide a resultant effective voltage (V M ) to said winding stages (a,b,c); second control means including means (166) for selectively setting the maximum amplitude of the effective voltage through said first control means; and means (74, 76) for commutating said winding stages by applying the effective voltage thereto in sequence; whereby said first and second control means jointly determine the angular velocity of said rotatable assembly and said at least one rotatable component selectively coupled thereto.

Claim 7

A laundering apparatus according to Claim 4 wherein the commutating -means (74, 76) includes a commutation circuit (76) responsive to the angular position of the rotatable assembly (1151) to provide commutation signals; and the apparatusfurther comprising: a plurality of commutation switching means (84, 86, 88) for connection in series with the respective winding stages (a, b, c); means (74) for applying the commutation signals in sequence to said commutation switching means to control their conductivity; a first common point (82) connected to one terminal of each of said winding stages; first diode means (230, 232, 234) separately connected between the other terminal of each of said winding stages and a second common point (236); said commutation switching means being connected between a third common point (80) and said other terminal of each of said winding stages; means (228) for electrically braking the rotation of said rotatable assembly (1151) to apply a negative torque to said rotatable assembly and to said at least one rotatable component coupled thereto, said braking means including an energy return circuit to connect a variable low impedance across said winding stages with said energy return circuit having capacitor means (238) connected between said first and second common points; first impedance means (240), first transistor means (242) and second diode means (244) for connection in series combination between said first and second common points; voltage divider means (246, 248) and second transistor means (250) for connection in series combination substantially between said second and third common points, said voltage divider means including second (24.6) and third (248) impedance means for respective connection at a fourth common point; the voltage at said fourth common point controlling the conductivity of said first transistor means (242); and means (96) for deriving a control signal representative of the actual angular velocity of said rotatable assembly; the control signal being applied to said second transistor means (250) to decrease the conductivity thereof whenever the actual angular velocity exceeds the angular velocity determined by said first and second control means, the decreased conductivity of said second transistor means being effective to increase the conductivity of said first transistor means; whereby energy generated upon the commutation of said winding stages is stored in said capacitor means for subsequent dissipation,, and the negative torque is variably applied to said rotatable assembly in proportion to the amount by which the actual angular velocity exceeds the angular velocity determined by said first and second control means.