Abstract:
Starter apparatuses are provided for multiple-winding motors. Such starters can function with a single/combined overload device/circuit, rather than requiring multiple overloads relays and separate overload trip circuits for each motor winding. A microcontroller can keep track of the applicable overload trip points and can control multiple discrete contactors appropriately, via a single/combined overload relay. For a specific implementation, additional and/or alternative desirable functionality can also be afforded, including universal voltage input, true power characteristic sensing for status output/annunciation, integrated damper control, and substantially automated trip point selection and/or implementation.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a nonprovisional of, and claims the benefit of priority from, U.S. Provisional Patent Application No. 61/531,610, filed Sep. 6, 2011, which is hereby incorporated by reference in its entirety 
     
    
     COPYRIGHT NOTICE 
       [0002]    © 2012 Cerus Industrial Corporation. A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 37 CFR §1.71(d), (e). 
       TECHNICAL FIELD 
       [0003]    The present application is directed to the field of motor starters, and, in particular, starters offering control and protection for motors having separable windings configured for multiple, discrete operating speeds and/or modes. 
       BACKGROUND 
       [0004]    In building automation systems, heating, ventilation, and air conditioning (HVAC) installations, pumping systems, and other industrial implementations, it is common to use starters or starter mechanisms to control and protect motors. Starters for motors and the like are generally well known in the art. Typical starters comprise thermal trip elements plus contactors to disconnect a motor from line power in the event of an undesirable operating condition. The National Electric Code (NEC) classifies combination starters as devices that provide thermal overload protection and motor disconnect functionality. 
         [0005]    Key components of a traditional starter include an electromagnetic contactor and an overload relay. The circuitry of such traditional starters offers both motor control and motor protection functionality via a single device that is ideally specifically selected or calibrated for the particular motor being controlled. Operation of the motor (e.g., starting and stopping the motor, etc.) can be controlled through modulation of the contactor, which includes separable contacts that are electromechanically/electromagnetically operated by an energized or de-energized coil. Closing the contacts allows line power to energize the motor, while opening the contacts cuts of power from the motor. 
         [0006]    As mentioned above, starters also are able to provide thermal protection (i.e., overload protection) to a motor to protect it against unfavorable operating conditions. Traditional starters typically include an overload relay provided for this purpose. Overload conditions occur when equipment is operated in an electrically undamaged circuit in excess of the normal full load current rating (e.g., the conductors carry current in excess of the rated amperage). The overload is detected by the overload relay with reference to the applicable current trip point (expressed as a trip curve, which designates trip points as a function of current and time for a given motor classification). Overload conditions persisting for a sufficient amount of time can damage the motor, conductors, or other equipment. The terms “overload”, “overload protection” and “overload relay” are defined by the National Electrical Manufacturers Association (NEMA) standard ICS2, which is hereby incorporated by reference in its entirety. In the past, typical overload relays were implemented using heater/detector elements, such as using bimetallic relays or thermal heater elements. More recently, however, electronic overloads have been increasingly used. Electronic overloads may include a current transformer or current sensor to detect and monitor current supplied to the motor. 
         [0007]    For simple electromechanical motors, which have a single winding driving the motor at a single intended speed upon application of a constant load, a traditional starter apparatus with control and overload protection functionality would suffice. However, for motors including multiple windings, capable of operating the motor at multiple, discrete speeds, or in multiple, discrete operating modes (e.g., such as a start mode/speed and/or a run mode/speed etc.), a starter with a single overload relay would be insufficient. For separable-winding motors, each motor winding has its own applicable overload characteristics. Accordingly, starters that operate motors having separable windings are required to employ overload relays and corresponding overload trip circuits for each separate winding in order to ensure that the proper level of thermal protection is afforded to the motor for each specific winding and for each separate, discrete operating speed/mode for the motor. Such systems require bulky and/or cumbersome installations and result in increased complexity and cost in equipment acquisition, installation, and maintenance. 
       SUMMARY 
       [0008]    While starters are well known in the art, present embodiments provide novel and nonobvious improvements to solve problems Applicants have discovered with conventional product offerings and traditional installations. Present embodiments can provide integrated novel and nonobvious functionality consolidated into a unitary starter housing, thus offering significant cost savings, facilitated installation/operation, and other advantages and/or improvements over conventional starters. Starters consistent with the present application can be employed for protection and control of the wide variety of separable-winding motors or configurable-winding motors that are commercially available. Some such motors are delta-wye motors, some are two-speed motors (either as two running speeds, or one speed to start and one to run), etc. However, consistent with the present application, present starter embodiments are intended for substantially any of such varied configurable-winding motors types. 
         [0009]    One advantageous aspect of present starter apparatuses is that they do not require multiple overloads relays and separate overload trip circuits for each motor winding. Present embodiments can employ one overload device by taking advantage of a programmable microcomputer/microcontroller that knows the applicable overload state and can appropriately and independently control multiple discrete contactors appropriately. For example, two or more contactors can be provided for a high or low run speed, or for alternative conditions such as a start condition and a run condition, as appropriate for the motor with multiple windings. The microcontroller can keep track of, and control the motor for operation within, the specific requirements of each speed or operating condition for each separate motor winding, including each corresponding level of overload protection required. Embodiments can be aware of the appropriate level overload protection required in each operating state and appropriately control a corresponding contactor according to the applicable overload protection requirements. 
         [0010]    Consistent with the present application, starter embodiments can also include additionally and/or alternatively desirable functionality, depending on the given installation. For example, such functionality, embodied in a separable-winding motor starter, can include universal voltage input, true power characteristic sensing for status output/annunciation, integrated damper control, and substantially automated trip point selection and/or implementation based, at least in part, on startup conditions and/or specified system parameters (e.g., full load amperage (FLA), motor classification, etc.). 
         [0011]    Additional aspects and advantages of this invention will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  illustrates one embodiment of a starter apparatus consistent with the claimed subject matter. 
           [0013]      FIG. 2  illustrates one embodiment of a system schematic for a starter embodiment consistent with the claimed subject matter. 
           [0014]      FIG. 3  depicts one embodiment of an operating methodology consistent with the claimed subject matter. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The following description discloses various embodiments and functionality associated with the starter apparatuses, systems, and methods for use, at least in part, in applications such as building automation, industrial systems automation, heating, ventilation, and air conditioning (HVAC) installations, and applications including the control and protection of motors and electro mechanical devices driven by motors, such as pumps, fans, conveyor belts, etc., to name but a few illustrative examples systems presented for purposes of illustration and not by way of limitation. 
         [0016]    In particular, the subject matter of the present application and the detailed starter embodiments described herein are preferably adapted for one or more of the several variations of separable-winding motors or configurable-winding motors now known or later developed. Those skilled in the relevant art will appreciate that the present subject matter is applicable regardless of the specific type of separable-winding motor that is being controlled and/or protected. As but two examples, delta wye motors and/or two-speed motors (either having two running speeds, or one speed to start and one speed to run the motor), would be equally well suited for control and/or protection by starter embodiments consistent with the present subject matter. 
         [0017]    In one aspect, consistent with the present subject matter, starter functionality can be enabled, at least in part, through one or more embodiments of a starter control module (SCM) embodiment and related technology. An SCM can include components such as a meter base and a custom interface printed circuit board assembly to cooperatively facilitate motor control and/or protection. The specific electronics comprising the SCM can be further adapted, selected, and/or configured so as to facilitate optimization for an particular intended operating environment/application, such as to substantially represent an energy management starter (e.g., for HVAC implementations, etc.), a building automation starter (e.g., for industrial control applications, etc.), or an intelligent pump starter (e.g., for pump control applications, etc.). As used here, the term “starter control module” or “SCM” refers to the actual printed circuit board and related control board electronics and mechanical interfaces, rather than an entire integrated starter controller. For example, one SCM embodiment can be integrated into a single unitary enclosure along with an integrated overload relay and any required electromagnetic contactors to comprise a motor starter. However, a SCM embodiment can also be offered and/or employed modularly, such that it can be used as a standalone component to work with third-party supplied contactors, overload relays, and/or external current sensors, etc. 
         [0018]      FIG. 1  illustrates one embodiment of a starter control module consistent with the present subject matter. With particular reference to  FIG. 1 , the starter control module  100  is depicted as including a control board  102  and a meter base  104 . Meter base  104  of  FIG. 1  includes three current sensor embodiments  106   a  through  106   c . Control board  102  includes a microprocessor  108  functionally coupled with memory  110 , which can include firmware instructions and/or programmable memory storage. Control board  102  also can include a user interface assembly  112 . The user interface assembly embodiment  112  illustrated in  FIG. 1  includes two user selectable switches  114   a  through  114   b  as well as pilot light indicators  116  suitable for indicating to the user the present operating mode of starter control module  100 . Starter control module  100  is also depicted as having a terminal board  118 , illustrating but one example of an input/output wiring interface. Those skilled in the art will readily appreciate that additional, alternative, or fewer components than those illustrated in  FIG. 1  could also be employed consistent with the present subject matter. 
         [0019]    For further illustration, and to facilitate discussion,  FIG. 2  illustrates a schematic of one starter embodiment consistent with the claimed subject matter. A microprocessor-based printed circuit board for such a starter embodiment can employ unique customized firmware to, at least in part, provide the desired advantageous functionality. This can be embodied as a starter control board that can accommodate building automation control logic and communications. With particular reference to  FIG. 2 , a three-phase two-speed two-winding motor  200  operates on three-phase power lines  224 . The starter embodiment of  FIG. 2  includes a control board  102  and a meter base  104  similar to those depicted in  FIG. 1  and previously described. As illustrated in  FIG. 2 , the meter base  104  can include a voltage sensor and a current sensor. In one such embodiment, the current sensor can be a current transformer monitoring line current (however, those skilled in the art will appreciate that alternative current sensing mechanisms could also be implemented consistent with the claimed subject matter). Current sensor  106  provides a current measurement signal, voltage, or other output  222  suitable for metering and/or overload protection purposes. While  FIG. 2  illustrates one current sensor  106 , it is understood that current could be measured from one or more of the 3-phase power lines  224 . Meter base  104  of  FIG. 2  also includes a voltage sensor  232  for monitoring line voltage. Similarly, voltage could be measured from one or more of the 3-phase power lines  224 . Such an embodiment can substantially accommodate wide-range power supply and wide-range voltage sensing. Measuring both current and voltage also affords embodiments consistent with the present subject matter the ability to calculate true power consumption. 
         [0020]    Continuing with the starter embodiment illustrated in  FIG. 2 , control board  102  can also include user interface controls, such as a hand-off-auto control source switch  208  and the low-off-high motor speed switch  210 . Control source switch  208  allows a user to select between operating the starter embodiment by hand commands, such as through the use of the motor speed switch  210 , or commands driven from a remote controller, such as might be implemented in a building automation system. Accordingly, control board  102  is configured for receiving multiple control inputs, such as an auto-low command  212  an auto-high command  214  and a shutdown command  216 . Suitable output signals can also be generated by control board  102 , such as run status signal  218  or fault signal  220 . 
         [0021]    A particularly advantageous aspect of starter embodiments, such as that illustrated in  FIG. 2 , includes the ability of a single control board  102  to control/operate and protect two-speed motor  200  in either and/or both speeds/modes. Consistent with the present subject matter, motor control board  102  can be employed to control and protect motor  200  via coordinated operation of high speed contactor  202 , including separable contacts  228 , and/or low speed contactor  204 , including separable contacts  230 . One substantial benefit of such embodiment is the ability to avoid having to use multiple overload relays, one for each contactor  202 ,  204 . As illustrated in the starter embodiment of  FIG. 2 , a single overload relay, which can be integrated with meter base  104  to use current measurement  222  can provide overload protection to motor  200  via both contactors  202 ,  204 . Control board  102  monitors the operating state and appropriately controls the two contactors as instructed by way of input signals  212 ,  214 ,  216 , and/or user interface switches  208 ,  210 . 
         [0022]    One or more multiple-winding motor starter embodiments, consistent with the present subject matter, are substantially able to store and/or implement two trip points, one for each potential circuit being powered. Preferably, the contactors are cooperatively, yet independently operated such that they can substantially avoid being simultaneously energized. In one embodiment, low speed contactor  204  and high speed contactor  202  are separated by a mechanical interlock  206  such that control board  102  will avoid providing control signal outputs to both contactors  202 ,  204  at the same time. The embodiment can also implement a time delay (e.g., 0.3 seconds, etc.) before activating any contactor, thus helping prevent a mechanical jam in the interlock mechanism  206 . Of course, the 0.3 second delay example is provided for illustrative purposes only. Those skilled in the art will readily appreciate that longer, or slower delays could also be employed consistent with the present subject matter. Additionally, the time delay may or may not be made to be adjustable/configurable and/or removable by end users. 
         [0023]    Continuing with  FIG. 2 , control board  102  can include a status output relay to provide a run status indication  218  as a built-in feature. Such embodiments can use the same sensors for multiple aspects of alternative functionality. For example, current sensor  106 , can be used to provide overload protection and a run status indication  218 . In applications such as HVAC control and protection, if an undesirable situation happened such as a belt breaking and the current correspondingly drops, status output can be provided to indicate the condition. This can happen with or without a corresponding trip command being given. Control board  102  can also offer energy management functionality. Monitored current  222  via current sensor  106  and voltage via voltage sensor  232  can substantially allow for power metering at meter base  104 . Because voltage can be monitored via voltage sensor  232 , run status indications  222  can also be based on true power (not just current). By monitoring both voltage and current a truer sense of power can be achieved. This allows for tighter tolerances more precise control and can do a better job in detecting undesirable occurrences such as belt loss on a motor drive, etc. For an additional advantageous aspect, one or more starter embodiments can employ manual and/or self-calibrating overloads to provide both status indication and overload protection in a combined device. The functionality of such embodiments can also include auto sensing for status annunciation based on the monitored current  222  being at least a pre-specified percentage of full-load amperage (FLA). The FLA can be initially provided to control board  102  operating memory for each motor winding, or automatically determined via a self-calibrating overload circuit/relay. 
         [0024]    The following description illustrates one embodiment of an operating methodology for a two-speed motor starter embodiment (such as that illustrated in  FIG. 2 , as but one example). In such an embodiment, the two-speed two-winding starter is designed based on one or more previously discussed control board features. In particular, present starter embodiments have two separate motor full load current/amperage settings (one for each winding), two auto start inputs (Auto Low and Auto High), and a deceleration timer setting, to allow for sufficient deceleration of the motor before engaging a contactor to drive the motor at a lower speed than that at which the motor was previously operating. 
         [0025]      FIG. 3  illustrates one embodiment of steps that may be included in a starter methodology consistent with the present subject matter. With particular reference to  FIG. 3 , the process begins at by determining which control source is indicated by the control switch  300 . If the HOA switch is in Hand position  302  and starter is not in Shutdown mode  304  (in which case the starter would await an alternate control command  340 ) and speed switch  306  is set to Low-speed  310  or High-speed  308  position, the starter embodiment can provide output to operate Low-speed contactor  312  or High-speed contactor  314  accordingly, and the corresponding operative overload current setting can be changed to the value corresponding to that winding setting selected ( 316  for Low-speed winding and  318  for High-speed winding). Embodiments can employ a cooling timer, employed, at least in part, to help ensure a sufficient amount of time passes between switching contactors being operated (to help avoid jams, signal conflicts, etc.). Once the appropriate contactor and trip point settings are implemented, cooling timer can be reset  320 . In one embodiment, if the speed switch position was changed from High to Off and then to Low, a deceleration timer  342  can provide a time delay before engaging Low-speed contactor, measured from when the High-speed switch input was disabled. If High speed is started again, the deceleration timer can be reset. Because each setting and contactor can operate as a separate, independent circuit, If the starter trips on an overload condition in one speed setting, the other speed setting can be implemented with its own overload setting. 
         [0026]    Continuing with  FIG. 3 , if HOA switch  300  is in Auto position  322  and the starter is not in Shutdown mode  324  the starter determines what Auto input is being received  326 . If Auto Low-speed input  330  or Auto High-speed input  328  is active, the starter operates to provide output to Low-speed contactor  334  or High-speed contactor  332 , respectively, and the appropriate corresponding overload current setting is employed ( 336  for High-speed winding and  338  for Low-speed winding). After a contactor is selected/energized, cool timer  320  can be reset. Similar to operation in the Hand setting, in the Auto setting, if Auto High-speed input is disabled, a deceleration timer  346  can be employed, at least in part, to help provide a sufficient time delay before operating the Low-speed contactor  334 , measured from the when the Auto High-speed input  328  was disabled. If High-speed contactor  332  is started again, the deceleration timer can be reset. If the starter embodiment trips on overload in any selected speed, another speed can be started with its own corresponding overload setting. When operating the Auto mode  322 , a starter embodiment can employ a methodology wherein if HOA switch is in Auto position  322  and both Auto inputs  328 ,  330  are active/received, the starter can activate High-speed contactor  332  and deceleration timer  346  will be activated if/when Auto High-speed input is disabled. 
         [0027]    Depending, at least in part, on the operating environment or implementation in which the starter is employed, starter embodiments can include additional steps for additional advantageous features. For example, a run status output can be activated based on an active power consumption level being calculated that is at least a predetermined percentage of the activated winding&#39;s FLA setting. Also, starters consistent with the present subject matter can include additional advantageous functionality controlled, at least in part, by the control board. One such example could include AC or DC damper control functionality, as but one example. 
         [0028]    It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.