US 6,640,372 B2Granted

Method and apparatus for detecting load unbalance in an appliance

AssigneeWhirlpool Corporation

InventorsRosario Ciancimino, Brenner Martin Sharp, Gerald C. Stenger

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method and apparatus for determining load unbalance in an appliance is provided for an appliance having a vessel configured to receive a supply of material and rotatable about an axis. A control is arranged and configured to accelerate a rotation of the vessel between a series of constant rotational speeds, measure an amount of current with which the motor draws in rotating the vessel at each of the rotational speeds and during each acceleration period, compare the amount of current with a calculated threshold value for each speed and each acceleration period and send a signal indicative of an unbalance condition if the amount of energy exceeds the precalculated threshold value. The vessel may be rotated by use of an electric motor such as a controlled induction motor and the control can be used to measure the electric current drawn by the motor. The threshold values can further be adjusted by comparing the actual line voltage supplied to the motor with a predetermined nominal line voltage.

In an appliance with a vessel for holding a supply of material, said vessel being rotatable by operation of an electric motor, a method comprising the steps:

A. determining an amount of electrical current required by said motor to rotate said vessel at various predetermined speeds and at predetermined acceleration rates between said various predetermined speeds;
B. calculating a separate threshold value above said determined amount of current for each of said predetermined speeds and acceleration rates;
C. charging said vessel with said supply of material;
D. then rotating said vessel about an axis at a first one of said predetermined speeds with said electric motor;
E. then determining an amount of electrical current used by said motor to rotate said vessel at said first predetermined speed;
F. then comparing said amount of electrical current with said calculated value for said first speed;
G. then sending a signal indicative of an unbalance condition if said amount of current exceeds said calculated value;
H. then accelerating said vessel for an acceleration period to a higher predetermined speed if said amount of current is below said calculated value;
I. then determining an amount of electrical current used by said motor to accelerate said vessel to said next higher predetermined speed;
J. then comparing said amount of electrical current with said calculated value for said acceleration period;
K. then sending a signal indicative of an unbalance condition if said amount of current exceeds said calculated value for said acceleration period;
L. then determining an amount of electrical current used by said motor to rotate said vessel at said next higher predetermined speed;
M. then comparing said amount of electrical current with said calculated value for said next higher speed;
N. then sending a signal indicative of an unbalance condition if said amount of current exceeds said calculated value for said next higher speed;
and
O. repeating steps H through N until either a signal indicative of an unbalance condition is sent or a maximum predetermined speed is achieved.

13 more elements

Facts

Application

09/885,644Filed 20 Jun 2001 · us provisional application

Priority

26 Jun 2000

Published

US 2001/0054204 A127 Dec 2001

Granted

4 Nov 2003

Term ends

Not estimatedThe source records don’t support an estimate.

Classification3 codes

D06F 33/48
Control of washing machines characterised by the purpose or target of the control: preventing or reducing imbalance or noise
D06F 2103/26
Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers: imbalance; Noise level
D06F
Laundering, drying, ironing, pressing or folding textile articles

Abstract

Claims19