Patent Publication Number: US-2023134278-A1

Title: Washing machine appliance and method for flood protection operation

Description:
FIELD 
     The present subject matter relates generally to washing machine appliances, or more specifically, to systems and methods for flood protection in a washing machine appliance. 
     BACKGROUND 
     Washing machine appliances generally include a cabinet which receives a wash tub for containing water or wash fluid (e.g., water and detergent, bleach, or other wash additives). The wash tub may be suspended within the cabinet by a suspension system to allow some movement relative to the cabinet during operation. A wash basket is rotatably mounted within the wash tub and defines a wash chamber for receipt of articles for washing. A drive assembly is coupled to the wash tub and is configured to selectively rotate the wash basket within the wash tub. 
     Washing machine appliances are typically equipped to operate in one or more modes or cycles, such as wash, rinse, and spin cycles. For example, during a wash or rinse cycle, the wash fluid is directed into the wash tub in order to wash and/or rinse articles within the wash chamber. In addition, the wash basket and/or an agitation element can rotate at various speeds to agitate or impart motion to articles within the wash chamber. During a spin cycle, the wash basket may be rotated at high speeds, e.g., to wring wash fluid from articles within the wash chamber. 
     Washing machine appliances generally include a sensor, such as a pressure sensor or pressure switch, configured to detect the water level in the wash tub. The sensor or switch adds cost to the product, can be prone to failure, or may be of limited availability due to materials or supply chain limitations (e.g., limitations related to electric or electronic components). Such sensors may generally determine whether a washing appliance may proceed to the next cycle or mode or whether further draining or water supply is necessary. Such sensors may also determine how much water may be added or removed from the wash tub. 
     If such sensors fail, the washing machine appliance may not be able to proceed with further cycle steps, or continued operation under deleterious conditions may occur. Sensor failure may allow the washing machine appliance to overfill or flood due to erroneous water level signals. Erroneous water level signals may include high readings due to insufficient drainage 
     As such, a system and method for operating a washing machine appliance without such a sensor would be advantageous. Furthermore, a system and method for determining fault or failure at one or more sensors or component assemblies at a washing machine appliance would be advantageous. 
     BRIEF DESCRIPTION 
     Advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
     An aspect of the present disclosure is directed to a washing machine appliance including a wash tub positioned within a cabinet and a wash basket rotatably mounted within the wash tub. A motor assembly is operably coupled to the wash basket for selectively rotating the wash basket. A drain pump assembly is fluidly coupled to the wash tub for selectively draining wash fluid from the wash tub. A controller is operably coupled to the motor assembly and the drain pump assembly. The controller is configured to rotate the wash basket to at least a desired speed; determine whether the wash basket is rotated to at least the desired speed within a period of time; generate an output signal corresponding to fluid detection at the wash tub when the wash basket fails to rotate to at least the desired speed within the period of time. 
     Another aspect of the present disclosure is directed to a washing machine appliance including a wash tub positioned within a cabinet, a wash basket rotatably mounted within the wash tub and defining a wash chamber, a motor assembly operably coupled to the wash basket for selectively rotating the wash basket, a drain pump assembly fluidly coupled to the wash tub for selectively draining wash fluid from the wash tub, and a controller operably coupled to the motor assembly and the drain pump assembly. The controller is configured to rotate the wash basket to at least a desired speed; determine whether an energy parameter threshold of the motor assembly is exceeded when rotating the wash basket within the period of time; and generate the output signal corresponding to fluid detection at the wash tub when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     Still another aspect of the present disclosure is directed to a controller for a washing machine appliance. The controller is configured to store instructions that, when executed by a processor, causes the washing machine appliance to perform operations. The operations include rotating a wash basket to at least a desired speed; determining one or more of whether at least the desired speed of the wash basket is achieved within a period of time, or whether an energy parameter threshold of a motor assembly is exceeded when rotating the wash basket within the period of time; and generating an output signal corresponding to fluid detection at a wash tub when the wash basket fails to rotate to at least the desired speed within the period of time or, when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     Yet another aspect of the present disclosure is directed to a method for operating a washing machine appliance. The method includes rotating a wash basket to at least a desired speed; determining one or more of whether at least the desired speed of the wash basket is achieved within a period of time, or whether an energy parameter threshold of a motor assembly is exceeded when rotating the wash basket within the period of time; and generating an output signal corresponding to fluid detection at a wash tub when the wash basket fails to rotate to at least the desired speed within the period of time or, when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures. 
         FIG.  1    provides a perspective view of a washing machine appliance according to an exemplary embodiment of the present subject matter with a door of the exemplary washing machine appliance shown in a closed position. 
         FIG.  2    provides a perspective view of the exemplary washing machine appliance of  FIG.  1    with the door of the exemplary washing machine appliance shown in an open position. 
         FIG.  3    provides a side cross-sectional view of the exemplary washing machine appliance of  FIG.  1   . 
         FIG.  4    illustrates a method for operating a washing machine appliance in accordance with one embodiment of the present disclosure. 
         FIG.  5    illustrates an exemplary graph depicting speed and an energy parameter at a washing machine appliance versus a period of time in accordance exemplary embodiments of the method for operating a washing machine appliance. 
         FIG.  6    provides a flow diagram of an exemplary process for implementing a fluid level detection method in a washing machine appliance according to an exemplary embodiment of the present subject matter. 
         FIG.  7    provides a flow diagram of an exemplary process for fluid detection without a fluid level sensor at a washing machine appliance. 
         FIG.  8    illustrates a method for operating a washing machine appliance in accordance with one embodiment of the present disclosure. 
         FIG.  9    provides a flow diagram of an exemplary process for determining sensor failure, sensor validation, and component failure at a washing machine appliance. 
     
    
    
     Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention. 
     DETAILED DESCRIPTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     As used herein, the terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. For example, the approximating language may refer to being within a 10 percent margin. 
     It should be appreciated that where a value is at a threshold, one skilled in the art may determine whether an action at the threshold may correspond to actions below the threshold or above the threshold. For instance, an action “below a threshold” may include values “at or below a threshold”. In another instance, an action “above a threshold” may include values “at or above a threshold”. One skilled in the art may alter the corresponding action of a value at or equal to a threshold without deviating from the scope of the present disclosure. 
     Embodiments of a washing machine appliance, a controller for a washing machine appliance, and a method for operating a washing machine appliance are provided. Embodiments provided herein allow for detection of presence of fluid (e.g., water or water-based solution) in a washer tub. Methods provided herein allow for determination of the presence of fluid within or outside of a wash cycle without requiring utilization of a fluid level sensor (e.g., a pressure sensor or switch, a load sensor or switch, a moisture sensor or switch, etc.). Embodiments provided herein may allow for detection of fluid presence in the wash tub while utilizing a fluid sensor, allowing for failure detection of a fluid level sensor or component, such as a drain pump assembly. Embodiments provided herein allow for sensor-less flood protection or fluid detection, fluid level sensor validation or failure determination, or determination of obstruction or non-operation of a wash drain or drain pump assembly. 
     Embodiments provided herein energize a motor assembly and rotate a wash basket to detect a characteristic signal indicative of fluid presence in a washer tub. The signal may include a measurement of time or rate of change in speed for the wash basket to perform one or more of accelerating from a first speed to a second speed, decelerating the wash basket from a first speed to a second speed, meeting or exceeding a rotational speed threshold of the wash basket after the motor assembly is energized for a predetermined period of time, and/or meeting or exceeding an energy parameter of the motor assembly within a predetermined period of time following energizing the motor assembly. Embodiments provided herein allow for determining fluid presence, fluid sensor fault, and/or drain pump fault based on whether one or more speed and/or energy parameter thresholds is met or exceeded within the period of time. 
     As used herein, “energy parameter” or “energy parameter threshold” refers to power, current, or voltage. Embodiments of the washing machine appliance and methods provided herein allow for utilizing a measurement, detection, or calculation of power, voltage, or current of the motor assembly for detection of presence of fluid at a wash tub, sensor-less flood protection or fluid detection, fluid level sensor validation or failure determination, or determination of obstruction or non-operation of a wash drain or drain pump assembly. 
     Embodiments of the washing machine appliance and methods provided herein allow for production and operation of washing machine appliances that do not require fluid level sensors, which may lower cost, improve reliability, or reduce false signals indicative of component or sensor failure (e.g., increased robustness in fault condition detection). 
       FIGS.  1  through  3    illustrate an exemplary embodiment of a vertical axis washing machine appliance  100 . Specifically,  FIGS.  1  and  2    illustrate perspective views of washing machine appliance  100  in a closed and an open position, respectively.  FIG.  3    provides a side cross-sectional view of washing machine appliance  100 . Washing machine appliance  100  generally defines a vertical direction V, a lateral direction L, and a transverse direction T, each of which is mutually perpendicular, such that an orthogonal coordinate system is generally defined. 
     While described in the context of a specific embodiment of vertical axis washing machine appliance  100 , it should be appreciated that vertical axis washing machine appliance  100  is provided by way of example only. It will be understood that aspects of the present subject matter may be used in any other suitable washing machine appliance, such as a horizontal axis washing machine appliance. Indeed, modifications and variations may be made to washing machine appliance  100 , including different configurations, different appearances, and/or different features while remaining within the scope of the present subject matter. 
     Washing machine appliance  100  has a cabinet  102  that extends between a top portion  104  and a bottom portion  106  along the vertical direction V, between a first side (left) and a second side (right) along the lateral direction L, and between a front and a rear along the transverse direction T. As best shown in  FIG.  3   , a wash tub  108  is positioned within cabinet  102 , defines a wash chamber  110 , and is generally configured for retaining wash fluids during an operating cycle. Washing machine appliance  100  further includes a primary dispenser  112  ( FIG.  2   ) for dispensing wash fluid into wash tub  108 . The term “wash fluid” refers to a liquid used for washing and/or rinsing articles during an operating cycle and may include any combination of water, detergent, fabric softener, bleach, and other wash additives or treatments. 
     In addition, washing machine appliance  100  includes a wash basket  114  that is positioned within wash tub  108  and generally defines an opening  116  for receipt of articles for washing. More specifically, wash basket  114  is rotatably mounted within wash tub  108  such that it is rotatable about an axis of rotation A. According to the illustrated embodiment, the axis of rotation A is substantially parallel to the vertical direction V. In this regard, washing machine appliance  100  is generally referred to as a “vertical axis” or “top load” washing machine appliance  100 . However, it should be appreciated that aspects of the present subject matter may be used within the context of a horizontal axis or front load washing machine appliance as well. 
     As illustrated, cabinet  102  of washing machine appliance  100  has a top panel  118 . Top panel  118  defines an opening ( FIG.  2   ) that coincides with opening  116  of wash basket  114  to permit a user access to wash basket  114 . Washing machine appliance  100  further includes a door  120  which is rotatably mounted to top panel  118  to permit selective access to opening  116 . In particular, door  120  selectively rotates between the closed position (as shown in  FIGS.  1  and  3   ) and the open position (as shown in  FIG.  2   ). In the closed position, door  120  inhibits access to wash basket  114 . Conversely, in the open position, a user can access wash basket  114 . A window  122  in door  120  permits viewing of wash basket  114  when door  120  is in the closed position, e.g., during operation of washing machine appliance  100 . Door  120  also includes a handle  124  that, e.g., a user may pull and/or lift when opening and closing door  120 . Further, although door  120  is illustrated as mounted to top panel  118 , door  120  may alternatively be mounted to cabinet  102  or any other suitable support. 
     As best shown in  FIGS.  2  and  3   , wash basket  114  further defines a plurality of perforations  126  to facilitate fluid communication between an interior of wash basket  114  and wash tub  108 . In this regard, wash basket  114  is spaced apart from wash tub  108  to define a space for wash fluid to escape wash chamber  110 . During a spin cycle, wash fluid within articles of clothing and within wash chamber  110  is urged through perforations  126  wherein it may collect in a sump  128  defined by wash tub  108 . Washing machine appliance  100  further includes a pump assembly  130  ( FIG.  3   ) that is located beneath wash tub  108  and wash basket  114  for gravity assisted flow when draining wash tub  108 . 
     An impeller or agitation element  132  ( FIG.  3   ), such as a vane agitator, impeller, auger, oscillatory basket mechanism, or some combination thereof is disposed in wash basket  114  to impart an oscillatory motion to articles and liquid in wash basket  114 . More specifically, agitation element  132  extends into wash basket  114  and assists agitation of articles disposed within wash basket  114  during operation of washing machine appliance  100 , e.g., to facilitate improved cleaning. In different embodiments, agitation element  132  includes a single action element (i.e., oscillatory only), a double action element (oscillatory movement at one end, single direction rotation at the other end) or a triple action element (oscillatory movement plus single direction rotation at one end, single direction rotation at the other end). As illustrated in  FIG.  3   , agitation element  132  and wash basket  114  are oriented to rotate about axis of rotation A (which is substantially parallel to vertical direction V). 
     As best illustrated in  FIG.  3   , washing machine appliance  100  includes a drive assembly or motor assembly  138  in mechanical communication with wash basket  114  to selectively rotate wash basket  114  (e.g., during an agitation or a rinse cycle of washing machine appliance  100 ). In addition, motor assembly  138  may also be in mechanical communication with agitation element  132 . In this manner, motor assembly  138  may be configured for selectively rotating or oscillating wash basket  114  and/or agitation element  132  during various operating cycles of washing machine appliance  100 . 
     More specifically, motor assembly  138  may generally include one or more of a drive motor  140  and a transmission assembly  142 , e.g., such as a clutch assembly, for engaging and disengaging wash basket  114  and/or agitation element  132 . According to the illustrated embodiment, drive motor  140  is a brushless DC electric motor, e.g., a pancake motor. However, according to alternative embodiments, drive motor  140  may be any other suitable type or configuration of motor. For example, drive motor  140  may be an AC motor, an induction motor, a permanent magnet synchronous motor, or any other suitable type of motor. In addition, motor assembly  138  may include any other suitable number, types, and configurations of support bearings or drive mechanisms. 
     Referring to  FIGS.  1  through  3   , washing machine appliance  100  may include one or more speed sensors  180  for detecting a rotational speed of the wash basket  114 . The speed sensor  180  may be mounted to the cabinet  102 , the door  120 , or any other appropriate position at the washing machine appliance  100  for detecting rotational speed. The speed sensor  180  may be configured to determine one or more discrete or transient speeds of rotary components of the washing machine appliance. Certain embodiments may configure the speed sensor  180  as a speed switch configured to determine whether a rotational speed threshold has been met or exceeded, such as described with regard to one or methods herein. Speed sensor  180  may include various components for detecting a rotational speed, such as a housing  182  and a sensor element  184 . The speed sensor may be configured as any appropriate type of sensor for detecting component rotational speed, such as, but not limited to, a magneto-resistive sensor, a Hall effect sensor, or an inductive sensor. 
     Referring still to  FIGS.  1  through  3   , a control panel  150  with at least one input selector  152  ( FIG.  1   ) extends from top panel  118 . Control panel  150  and input selector  152  collectively form a user interface input for operator selection of machine cycles and features. A display  154  of control panel  150  indicates selected features, operation mode, a countdown timer, and/or other items of interest to appliance users regarding operation. 
     Operation of washing machine appliance  100  is controlled by a controller or processing device  156  that is operatively coupled to control panel  150  for user manipulation to select washing machine cycles and features. In response to user manipulation of control panel  150 , controller  156  operates the various components of washing machine appliance  100  to execute selected machine cycles and features. The control panel  150  and/or controller  156  is configured in operative communication with one or more sensors (e.g., sensor  180 , sensor  170 ), such as to receive and communicate via output signals, fault signals, validation signals, power output or consumption signals, current signal, voltage signal, or other energy parameter signal, speed signals, or thresholds, such as further described herein. According to an exemplary embodiment, controller  156  may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with methods described herein. Alternatively, controller  156  may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel  150  and other components of washing machine appliance  100  may be in communication with controller  156  via one or more signal lines or shared communication busses. 
     During operation of washing machine appliance  100 , laundry items are loaded into wash basket  114  through opening  116 , and washing operation is initiated through operator manipulation of input selectors  152 . Wash basket  114  is filled with water and detergent and/or other fluid additives via primary dispenser  112 . One or more valves can be controlled by washing machine appliance  100  to provide for filling wash tub  108  and wash basket  114  to the appropriate level for the amount of articles being washed and/or rinsed. By way of example for a wash mode, once wash basket  114  is properly filled with fluid, the contents of wash basket  114  can be agitated (e.g., with agitation element  132  as discussed previously) for washing of laundry items in wash basket  114 . 
     More specifically, referring again to  FIG.  3   , a water fill process will be described according to an exemplary embodiment. As illustrated, washing machine appliance  100  includes a water supply conduit  160  that provides fluid communication between a water supply source  162  (such as a municipal water supply) and a discharge nozzle  164  for directing a flow of water into wash chamber  110 . In addition, washing machine appliance  100  includes a water fill valve or water control valve  166  which is operably coupled to water supply conduit  160  and communicatively coupled to controller  156 . In this manner, controller  156  may regulate the operation of water control valve  166  to regulate the amount of water within wash tub  108 . 
     Although water supply conduit  160 , water supply source  162 , discharge nozzle  164 , and water control valve  166  are all described and illustrated herein in the singular form, it should be appreciated that these terms may be used herein generally to describe a supply plumbing for providing hot and/or cold water into wash chamber  110 . In this regard, water supply conduit  160  may include separate conduits for receiving hot and cold water, respectively. Similarly, water supply source  162  may include both hot- and cold-water supplies regulated by dedicated valves. In addition, washing machine appliance  100  may include one or more fluid level sensors  170  for detecting the amount of water and or clothes within wash tub  108 . For example, fluid level sensor  170  may be operably coupled to a side of tub  108  for detecting the weight, load, or pressure of wash tub  108 , which controller  156  may use to determine a volume of water in wash chamber  110  and a sub-washer load weight. The fluid level sensor  170  may form a sensor configured to determine one or more discrete values of pressure, load, weight, or moisture. Certain embodiments of the fluid level sensor  170  may form a switch configured to determine whether a threshold value has been met or exceeded. 
     After wash tub  108  is filled and the agitation phase of the wash cycle is completed, wash basket  114  can be drained, e.g., by drain pump assembly  130 . Laundry articles can then be rinsed by again adding fluid to wash basket  114  depending on the specifics of the cleaning cycle selected by a user. The impeller or agitation element  132  may again provide agitation within wash basket  114 . One or more spin cycles may also be used as part of the cleaning process. In particular, a spin cycle may be applied after the wash cycle and/or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, wash basket  114  is rotated at relatively high speeds to help wring fluid from the laundry articles through perforations  126 . During or prior to the spin cycle, drain pump assembly  130  may operate to discharge wash fluid from wash tub  108 , e.g., to an external drain. After articles disposed in wash basket  114  are cleaned and/or washed, the user can remove the articles from wash basket  114 , e.g., by reaching into wash basket  114  through opening  116 . 
     While described in the context of a specific embodiment of vertical axis washing machine appliance  100 , using the teachings disclosed herein it will be understood that vertical axis washing machine appliance  100  is provided by way of example only. Other washing machine appliances having different configurations, different appearances, and/or different features may also be utilized with the present subject matter as well, e.g., horizontal axis washing machine appliances. In addition, aspects of the present subject matter may be utilized in a combination washer/dryer appliance. 
     Now that the construction of washing machine appliance  100  and the configuration of controller  156  according to exemplary embodiments have been presented, an exemplary method  1000  of operating a washing machine appliance will be described (hereinafter, “method  1000 ”). Although the discussion below refers to the exemplary method  1000  of operating washing machine appliance  100 , one skilled in the art will appreciate that the exemplary method  1000  is applicable to the operation of a variety of other washing machine appliances, such as horizontal axis washing machine appliances. In exemplary embodiments, the various method steps as disclosed herein may be performed by controller  156  or a separate, dedicated controller. Steps of the method  1000  may be stored as instructions in one or more memory devices associated with the controller  156 . Steps of the method  1000  may be executed by embodiments of the motor assembly  138  and drain pump assembly  130  such as provided herein. Accordingly, the controller  156  or other control device may be configured to perform operations such as provided in one or more steps of the method  1000 . 
     Referring now to  FIG.  4   , a flowchart outlining exemplary steps of the method  1000  of operating a washing machine appliance is provided. The method  1000  includes at  1010  rotating a wash basket (e.g., wash basket  114 ) to at least a desired speed. The desired speed may correspond to one or more speeds for performing a spin cycle at a washing machine appliance. It should be appreciated that the spin cycle may include any cycle at which the wash basket is rotated to or toward a desired speed without the addition of fluid during rotation, or following draining of fluid prior to rotation, or any other appropriate cycle step at which fluid at the wash basket and/or wash tub is expected or have been removed prior to commencing the spin cycle. The method  1000  may further include rotating the wash basket to at least a desired speed for a period of time. Rotating the wash basket may include energizing the motor assembly (e.g., motor assembly  138 ), such as providing an energy parameter (e.g., power or current) to the motor assembly, to rotate the wash basket. 
     The method  1000  includes at  1020  determining whether at least the desired speed of the wash basket is achieved within a period of time. The method  1000  includes at  1030  generating an output signal corresponding to fluid detection at a wash tub (e.g., wash tub  108 ) when the wash basket fails to rotate to at least the desired speed within the period of time. 
     Referring briefly to  FIG.  5   , an exemplary graph  500  depicting an energy parameter (at axis  502 ) versus time (at axis  501 ) is provided in accordance with embodiments of the method  1000 . Graph  500  further depicts wash basket speed (at axis  503 ) versus time  501 . Line  510  depicts a target threshold speed, such as the desired speed in accordance with the method  1000  at step  1010 . The target threshold speed may correspond to a desired rotational speed of a wash basket for performing a spin cycle. Line  514  depicts an exemplary speed of the wash basket over the period of time when no fluid is present in the wash basket or wash tub. Line  512  depicts an exemplary speed of the wash basket over the period of time when fluid is present at the wash basket or wash tub. When fluid is present in the wash tub, such as depicted at line  512 , the rotational speed of the wash basket fails to meet or exceed the target speed threshold  510  within the period of time. When fluid is not present in the wash tub, such as depicted at line  514 , the rotational speed of the wash basket meets or exceeds the target speed threshold  510  within the period of time. 
     Referring still to  FIG.  5   , line  520  depicts a target power or current usage threshold, such as the desired power or current utilized by the motor assembly. The target power or current may correspond to the target threshold speed. For instance, the power or current may correspond to a predetermined value for meeting or exceeding the target threshold speed when fluid is not present in the wash tub. In another embodiment, the power or current may correspond to a predetermined value based on a desired energy usage of the washing machine appliance. Line  524  depicts an exemplary power or current usage of the motor assembly when no fluid is present at the wash basket or wash tub. Line  522  depicts an exemplary power or current usage at the motor assembly over the period of time when fluid is present at the wash basket or wash tub. When fluid is present in the wash tub, such as depicted at line  522 , the power or current usage at the motor assembly exceeds the target power or current usage threshold  520  within the period of time. When fluid is not present in the wash tub, such as depicted at line  524 , the power or current usage of the motor assembly does not exceed the target power or current usage threshold  520  within the period of time. 
     It should be appreciated that the term “fluid not present” or “fluid not detected” is relative to a minimum fluid level threshold desired or allowed for operation of the washing machine appliance. Accordingly, “fluid not present” or “fluid not detected” may correspond to a minimum pressure or load at the wash basket and/or wash tub, a minimum fluid level or height, or a minimum moisture content, or combinations thereof, as should be appreciated by one skilled in the art for washing machine appliances. 
     Referring back to  FIG.  4   , in certain embodiments, the method  1000  at  1020  includes obtaining, such as via a speed sensor, a speed signal corresponding to a measured, calculated, or otherwise obtained speed of rotation of the wash basket. 
     In various embodiments, the method  1000  includes at  1040  determining whether an energy parameter threshold of the motor assembly is exceeded when rotating the wash basket within the period of time, such as depicted with regard to  FIG.  5   . The method  1000  may further include at  1042  generating the output signal corresponding to fluid detection at the wash tub when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     In certain embodiments, the method  1000  includes at  1050  commencing to a next cycle step or an abatement cycle step when the output signal corresponding to fluid detection at the wash tub is generated. The output signal may command an end to the spin cycle. The output signal may additionally, or alternatively, command commencement of the next desired cycle or an abatement cycle. In a particular embodiment, the abatement cycle step may include a pump clearing cycle step. For instance, the abatement cycle step or pump clearing cycle step may include one or more commands or operations at the drain pump assembly, such as to scavenge and remove fluid from the wash tub and/or wash basket. 
     Referring now to  FIG.  6   , a flow diagram  600  of an exemplary process for fluid detection at a washing machine appliance is provided. Embodiments of the flow diagram  600  may include or form one or more steps of the method  1000  for operating a washing machine appliance such as provided with regard to  FIG.  4   . The flow diagram  600  includes commanding basket spin to the desired speed and spinning for a predetermined period of time, such as provided at step  1010  of the method  1000 . The flow diagram  600  determines whether the target speed threshold (e.g., threshold  510  in  FIG.  5   ) was achieved (e.g., met or exceeded), such as provided at step  1020  of the method  1000 . If the wash basket fails to achieve the target speed threshold (e.g., line  512  in  FIG.  5   ) then fluid is detected and the output signal may be generated accordingly, such as provided at step  1030 . If the wash basket meets or exceeds the target speed threshold, the method and process may then include determining whether power (or current) at the motor assembly was exceeded, such as provided at step  1040  of the method  1000 . If power at the motor assembly was exceeded (e.g., line  522  in  FIG.  5   ) then fluid is detected and the output signal may be generated, such as provided at step  1042  of the method  1000 . If power at the motor assembly was not exceeded (e.g., line  524  in  FIG.  5   ) then no fluid is detected at the wash tub. The method  1000  may include proceeding to a next cycle step or appropriate abatement cycle step, such as provided at step  1050  of the method  1000 . 
     Referring now to  FIG.  7   , a flow diagram  700  of an exemplary process for fluid detection without a fluid level sensor at a washing machine appliance is provided. The flow diagram  700  depicts steps that may form one or more “next cycle steps” as provided above with regard to step  1050  of the method  1000 . It should be appreciated that rotating the wash basket at step  1010  may include spinning the wash basket for a predetermined period of time prior to performing a wash cycle step, a rinse cycle step, or a spin cycle step. Embodiments of methods for operating a washing machine appliance may include starting or commencing the wash cycle, performing one or more steps of the method  1000  such as provided herein, filling the wash basket with washing fluid, performing and completing a wash step, draining the washing fluid, performing one or more steps of the method  1000 , filling the wash basket with a rinsing fluid, performing and completing a rinse step, draining the rinse fluid, performing one or more steps of the method  1000 , performing a spin cycle (e.g., to remove excess fluid from clothes or other wash articles), and ending the wash cycle. Although the flow diagram  700  depicts the serial arrangement of the steps provided above, it should be appreciated that certain steps may be started, restarted, rearranged, paused, or ended in any desired order by a controller or user input. 
     Referring now to  FIG.  8   , a flowchart outlining exemplary steps of a method for operating a washing machine appliance is provided (hereinafter, “method  1100 ”). Method  1100  may particularly provide a method for determining fault or failure at one or more sensors and/or drain pump assemblies at a washing machine appliance. Embodiments of the method  1100  provided herein may include one or more steps of the method  1000  provided herein. 
     Certain embodiments of the method  1100  include at  1105  determining, via a fluid level sensor, whether a fluid level at the wash tub is below or above a fluid level threshold. In a particular embodiment, the method  1100  includes at  1110  determining, via a fluid level sensor, whether a fluid level at the wash tub is at or below a fluid level threshold, and at  1120  determining, via a fluid level sensor, whether a fluid level at the wash tub is above a fluid level threshold. As provided above, the fluid level threshold may include a measurement or calculation of minimum fluid level or height, a minimum pressure or load, or a minimum moisture content. The method  1100  may include at  1112  generating a sensor fault signal indicative of fluid level sensor failure when the output signal is generated (e.g., step  1030 ) and when the fluid level at the wash tub is determined to be at or below the fluid level threshold. The method  1100  may include at  1114  generating a sensor fault signal indicative of fluid level sensor failure when the fluid level at the wash tub is determined to be above the fluid level threshold and when at least the desired speed of the wash basket is achieved within the period of time. The method  1100  may include at  1116  generating a sensor validation signal indicative of valid fluid level sensor operation when at least the desired speed of the wash basket is achieved within the period of time and the fluid level at the wash tub is at or below the fluid level threshold. 
     In various embodiments, the method  1100  may include at  1124  generating a pump fault signal indicative of drain pump assembly failure when the output signal (e.g., step  1030 ) is generated and when the fluid level at the wash tub is determined to be at or below the fluid level threshold. In a particular embodiment, the method  1100  determines at  1110  the wash tub is at or below a fluid level threshold and then at  1124  generates the pump fault signal. 
     Still certain embodiments of the method  1100  may include at  1122  generating a pump fault signal indicative of drain pump assembly failure when the output signal (e.g., step  1030 ) is generated and when the fluid level at the wash tub is determined to be above the fluid level threshold. In a particular embodiment, the method  1100  determines at  1120  the wash tub is above a fluid level threshold and then at  1122  generates the pump fault signal. In a still particular embodiment, the method  1100  additionally generates the sensor fault signal at  1114  and the pump fault signal at  1122 . 
     Referring now to  FIG.  9   , a flow diagram  900  of an exemplary process for operating a washing machine appliance such as provided in regard to the method flowchart of  FIG.  8   . The flow diagram  900  may particularly apply for determining sensor failure and/or pump failure at a washing machine appliance. Accordingly, the embodiment depicted in  FIG.  9    may particularly include a fluid level sensor (e.g., a pressure sensor, moisture sensor, a load sensor, or other appropriate device for determining the presence of fluid in a wash tub). The methods, processes, and flowcharts depicted in  FIGS.  8 - 9    may particularly allow for failure determination of a sensor and/or pump and/or sensor and/or pump operation validation. 
     Embodiments of the method  1100  may commence after completing a drain algorithm such as may be performed following any one or more process steps in  FIG.  7    denoted as “Drain”. A fluid level sensor determines whether there is a minimum fluid threshold of fluid in the wash tub, such as provided at  1105 ,  1110 , or  1120  of the method  1100 . The method may compare the determination of the fluid level sensor to the output of the fluid detection method  1000  when performed. 
     When the method  1000  determines that there is no fluid in the wash tub (e.g., via method  1000  at  1030 ) while the fluid level sensor determines that there is a minimum fluid threshold or less of fluid in the wash tub (e.g., at  1105  or  1110 ) then this indicates that the fluid level sensor is functioning properly and the sensor validation signal is generated (e.g., via method  1100  at  1116 ). When the method  1000  determines that there is fluid in the wash tub (e.g., via method  1000  at  1030 ) while the fluid level sensor determines that there is a minimum fluid threshold or less of fluid in the wash tub (e.g., at  1105  or  1110 ) then this indicates that the fluid level sensor is not functioning properly and a sensor fault signal is generated (e.g., via method  1100  at  1114 ). 
     When the method  1000  determines that there is fluid in the wash tub (e.g., via method  1000  at  1030 ) while the fluid level sensor determines that there is greater than a minimum fluid threshold (i.e., above the threshold) in the wash tub (e.g., at  1105  or  1120 ) then this indicates that the drain pump assembly (e.g., drain pump assembly  130 ) is not working properly, such as failing to sufficiently or completely drain the fluid from the wash tub. Accordingly, a pump fault signal (e.g., at  1122 ) is generated when the output signal is generated (e.g., at  1030 ) and when the fluid level at the wash tub is determined to be above the fluid level threshold. 
     When the method  1000  determines that there is not fluid in the wash tub (e.g., via method  1000  at  1030 ) while the fluid level sensor determines that there is greater than a minimum fluid threshold (i.e., above the threshold) in the wash tub (e.g., at  1105  or  1120 ) then this indicates that the fluid level sensor is not working properly. Accordingly, a sensor fault signal (e.g., at  1114 ) is generated when the fluid level at the wash tub is determined to be above the fluid level threshold and when at least the desired speed of the wash basket is achieved within the period of time. 
     Further aspects of the subject matter are provided by one or more of the following clauses: 
     A controller for a washing machine appliance, the controller storing instructions that, when executed by a processor, causes the washing machine appliance to perform operations, the operations including rotating a wash basket to at least a desired speed; determining one or more of whether at least the desired speed of the wash basket is achieved within a period of time, or whether an energy parameter threshold of a motor assembly is exceeded when rotating the wash basket within the period of time; and generating an output signal corresponding to fluid detection at a wash tub when the wash basket fails to rotate to at least the desired speed within the period of time or, when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     The controller of any one or more clauses herein, wherein determining whether at least the desired speed of the wash basket was achieved within the period of time includes obtaining, via a speed sensor, a speed signal corresponding to a measured speed of rotation of the wash basket. 
     The controller of any one or more clauses herein, the operations including commencing an abatement cycle when the output signal corresponding to fluid detection at the wash tub is generated. 
     The controller of any one or more clauses herein, the operations including determining, via a fluid level sensor, whether a fluid level at the wash tub is at or below a fluid level threshold; and generating a sensor fault signal indicative of fluid level sensor failure when the output signal is generated and when the fluid level at the wash tub is determined to be at or below the fluid level threshold. 
     The controller of any one or more clauses herein, the operations including determining, via a fluid level sensor, whether a fluid level at the wash tub is above a fluid level threshold; and generating a pump fault signal indicative of drain pump assembly failure when the output signal is generated and when the fluid level at the wash tub is determined to be above the fluid level threshold. 
     The controller of any one or more clauses herein, the operations including commencing a pump clearing cycle when the pump fault signal is generated. 
     The controller of any one or more clauses herein, the operations including determining, via a fluid level sensor, whether a fluid level at the wash tub is at or below a fluid level threshold; and generating a sensor fault signal indicative of fluid level sensor failure when the fluid level at the wash tub is determined to be above the fluid level threshold and when at least the desired speed of the wash basket is achieved within the period of time. 
     The controller of any one or more clauses herein, the operations including determining, via a fluid level sensor, whether a fluid level at the wash tub is at or below a fluid level threshold; and generating a sensor validation signal indicative of valid fluid level sensor operation when at least the desired speed of the wash basket is achieved within the period of time and the fluid level at the wash tub is at or below the fluid level threshold. 
     A washing machine appliance including the controller of any one or more clauses herein. 
     A washing machine appliance including a wash tub positioned within a cabinet; a wash basket rotatably mounted within the wash tub and defining a wash chamber; a motor assembly operably coupled to the wash basket for selectively rotating the wash basket; a drain pump assembly fluidly coupled to the wash tub for selectively draining wash fluid from the wash tub; and the controller of any one or more clauses herein operably coupled to the motor assembly and the drain pump assembly. 
     A method for operating a washing machine appliance, the method including rotating a wash basket to at least a desired speed; determining one or more of whether at least the desired speed of the wash basket is achieved within a period of time, or whether an energy parameter threshold of a motor assembly is exceeded when rotating the wash basket within the period of time; and generating an output signal corresponding to fluid detection at a wash tub when the wash basket fails to rotate to at least the desired speed within the period of time or, when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     A method for determining fault or failure at one or more sensors and/or drain pump assemblies at a washing machine appliance, the method including rotating a wash basket to at least a desired speed; determining one or more of whether at least the desired speed of the wash basket is achieved within a period of time, or whether an energy parameter threshold of a motor assembly is exceeded when rotating the wash basket within the period of time; and generating an output signal corresponding to fluid detection at a wash tub when the wash basket fails to rotate to at least the desired speed within the period of time or, when the energy parameter threshold is exceeded when rotating the wash basket within the period of time. 
     The method of any one or more clauses herein, the method including determining whether a fluid level at the wash tub is at or below a fluid level threshold; and generating a sensor fault signal indicative of fluid level sensor failure when the output signal is generated and when the fluid level at the wash tub is determined to be at or below the fluid level threshold. 
     The method of any one or more clauses herein, the method including determining whether a fluid level at the wash tub is above a fluid level threshold; and generating a pump fault signal indicative of drain pump assembly failure when the output signal is generated and when the fluid level at the wash tub is determined to be above the fluid level threshold. 
     The method of any one or more clauses herein, the method including commencing a pump clearing cycle when the pump fault signal is generated. 
     The method of any one or more clauses herein, the method including determining whether a fluid level at the wash tub is at or below a fluid level threshold; and generating a sensor fault signal indicative of fluid level sensor failure when the fluid level at the wash tub is determined to be above the fluid level threshold and when at least the desired speed of the wash basket is achieved within the period of time. 
     The method of any one or more clauses herein, the method including determining whether a fluid level at the wash tub is at or below a fluid level threshold; and generating a sensor validation signal indicative of valid fluid level sensor operation when at least the desired speed of the wash basket is achieved within the period of time and the fluid level at the wash tub is at or below the fluid level threshold. 
     A washing machine appliance configured to execute the method of any one or more clauses herein. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.