초록 ▼

A load in an electrical apparatus is driven by two motors M 1 , M 2 . Switching means (R 1 , R 2 ) switches the motors M 1 , M 2 between: a series configuration, in which the motors M 1 , M 2 are connected in series across a power supply and driven with a dc supply; and a parallel configuration in w

A load in an electrical apparatus is driven by two motors M 1 , M 2 . Switching means (R 1 , R 2 ) switches the motors M 1 , M 2 between: a series configuration, in which the motors M 1 , M 2 are connected in series across a power supply and driven with a dc supply; and a parallel configuration in which the motors M 1 , M 2 are connected in parallel across the power supply and driven with an ac supply. In the series configuration, a bridge rectifier BR is switched across the ac supply to provide the dc supply for the motors M 1 , M 2 and in the parallel configuration, the rectifier BR is removed from the circuit. The arrangement can be used to drive a drum of a washing machine or a load in some other kind of appliance.

대표청구항 ▼

1. A drive for driving a load in an electrical apparatus, comprising first and second motors coupled to a power supply, outputs of the motors being used to drive the load, and a switching structure for switching the motors between a series configuration, in which the motors are connected in series a

1. A drive for driving a load in an electrical apparatus, comprising first and second motors coupled to a power supply, outputs of the motors being used to drive the load, and a switching structure for switching the motors between a series configuration, in which the motors are connected in series across the power supply and driven with direct current; and a parallel configuration in which the motors are connected in parallel across the power supply and driven with alternating current. 2. A drive according to claim 1, wherein the switching structure connects the motors in the series configuration when the load is to be driven at a lower speed and in the parallel configuration when the load is to be driven at a higher speed. 3. A drive according to claim 1 or 2, further comprising a rectifier and wherein, in the series configuration, the switching structure switches the rectifier across an ac supply to provide direct current. 4. A drive according to claim 3, wherein, in the parallel configuration, the switching structure switches the rectifier out of the circuit. 5. A drive according to claim 1 or 2, further comprising a power switching device for switching power on and a controller for controlling the firing angle of the power switching device, the controller being arranged to vary the on time for the power switching device when switching between the series and parallel configurations. 6. A drive according to claim 1 or 2, further comprising means for reversing the direction of current flow through the motors when the motors are in the series configuration. 7. A drive according to claim 6, wherein the reversing means comprises a further switch structure which is coupled between an armature and rotor of each motor and is operable between a first configuration in which current flows through the motors in a first direction and a second configuration in which current flows through the motors in a second direction. 8. An electrical apparatus comprising a drive according to claim 1 or 2. 9. An electrical apparatus according to claim 8 in the form of a laundry appliance, wherein the load comprises a rotatable drum for retaining articles to be laundered. 10. A method of operating a drive for driving a load in an electrical apparatus, the drive comprising first and second motors coupled to a power supply and whose outputs are used to drive the load, and a switching structure, the method comprising:operating the switching structure so as to switch the motors between a series configuration in which the motors are connected in series across the power supply and driven with direct current and a parallel configuration in which the motors are connected in parallel across the power supply and driven with alternating current.