METHOD OF DETECTING AN OFF-BALANCE CONDITION OF A CLOTHES LOAD IN A WASHING MACHINE

• US 20130119909A1
• Filed: 01/30/2013
• Published: 05/16/2013
• Est. Priority Date: 08/16/2005
• Status: Active Grant

• Current Assignee: Fisher & Paykel Appliances Limited (Haier Group Company), Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: COOK, BENNETT J., CLEMONS, JASON L., SOARES NETO, MANOEL F., STANSEL, ANDREW C., DARBY, ADAM J.
• Granted Patent: US 8,918,937 B2
• Time in Patent Office: Days
• US Class Current: 318/434
• CPC Class Codes: D06F 2103/24 Spin speed; Drum movements
• CPC Class Codes: D06F 2103/26 Imbalance; Noise level
• CPC Class Codes: D06F 2103/46 of the motor driving the drum
• CPC Class Codes: D06F 33/48 Preventing or reducing imbalance or noise

Abstract

An off-balance detection method comprises a plurality of off-balance detection schemes that utilize wash basket speed to detect an off-balance load condition at speed ranges that span the entire spin cycle and include speeds corresponding to natural frequencies of a mass comprising a wash tub and a wash basket. The schemes can be used alone or in combination with one or more of the other schemes. The off-balance detection method can further comprise a power limiting method to prevent motor overload when an off-balance condition is present.

Claims

1. A method for controlling a spin speed of a wash basket driven by a motor in a washing machine, the method comprising:

detecting a line voltage from a power line that provides a voltage supply for the motor; and

limiting a maximum torque output of the motor based on the line voltage.

2. The method according to claim 1, wherein the detecting of the line voltage comprises measuring a DC rail voltage for the motor.

3. The method according to claim 2, wherein the measuring of the DC rail voltage comprises measuring the DC rail voltage for the motor at a constant spin speed of the wash basket.

4. The method according to claim 3, wherein the limiting of the maximum torque output occurs at spin speeds greater than the constant speed.

5. The method according to claim 1, wherein the limiting of the maximum torque output comprises setting a maximum advance angle for the motor.

6. The method according to claim 5, wherein the maximum advance angle for the motor is set between about 80 and 85 degrees.