Starter Apparatus, System, and/or Method for a Separable-Winding Motor

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

COPYRIGHT NOTICE

© 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

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

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.

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.

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.

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

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.

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.

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.).

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

FIG. 1 illustrates one embodiment of a starter apparatus consistent with the claimed subject matter.

FIG. 2 illustrates one embodiment of a system schematic for a starter embodiment consistent with the claimed subject matter.

FIG. 3 depicts one embodiment of an operating methodology consistent with the claimed subject matter.

DETAILED DESCRIPTION

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.

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.

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.

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 106a through 106c. 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 114a through 114b 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.

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.

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.

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.

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.

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.

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.

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.

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.

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'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.

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.

Claims

1. A starter system for a motor having separable windings, the system comprising: a starter control module configured for monitoring first control parameters for a first winding of a motor, and second control parameters for a second winding of the motor;a switching mechanism for selecting between a first operating mode setting for the motor and a second operating mode setting for the motor;a first contactor configured for selectively energizing the first winding of the motor in response to the switching mechanism indicating selection of the first operating mode,a second contactor configured for selectively energizing the second winding of the motor in response to the switching mechanism indicating selection of the second operating mode; andan overload protection device configured to offer thermal protection to the motor by:if the first operating mode is selected, opening the first contactor in response to an overload condition being detected consistent with the first control parameters; andif the second operating mode is selected, opening the second contactor in response an overload condition being detected consistent with the second control parameters.

2. The system of claim 1, wherein the switching mechanism is a user-selectable switch.

3. The system of claim 1, wherein the switching mechanism is a remote automation input signal.

4. The system of claim 1, wherein the starter control module is configured for providing at least one of a run status annunciation or fault annunciation.

5. The system of claim 1, further comprising a deceleration timer for facilitating delay of the second contactor energizing the second winding subsequent to the first contactor energizing the first winding, if the second operating mode operates the motor at a slower speed than the first operating mode.

6. The system of claim 1, further comprising a mechanical interlock to prevent conflicting operation of the first contactor and the second contactor.

7. The system of claim 1, wherein the first control parameters include a first full load amperage rating for the first winding and the second control parameters include a second full load amperage for the second winding.

8. The system of claim 1, wherein the starter control module further comprises a meter base configured for measuring at least one of line voltage or current.

9. A starter control apparatus for a separable-winding motor, comprising: a meter base for measuring current supplied to a motor;a starter control board including: a microprocessor based memory for storing first and second operating parameters corresponding to a first winding of the motor and a second winding of the motor, respectively;a control source input to receive a selection of the first winding or the second winding;a control output to selectively energize the first winding or the second winding consistent with the received selection; andan overload protection circuit configured to protect the motor operating with either the first winding or the second winding in response to a corresponding first overload current or second overload current being measured by the meter base.

10. A method for controlling a separable-winding motor, comprising: accepting the selection of a first operating mode or a second operating mode for a motor;in response to the first operating mode being selected, engaging a first contactor to energize a first winding of the motor, the first winding corresponding to the first operating mode and having first operating parameters;in response to the second operating mode being selected, engaging a second contactor to energize a second winding of the motor, the second winding corresponding to the second operating mode and having second operating parameters; andprovisioning an overload protection device to: protect the motor from overload consistent with the first operating parameters if the first operating mode is selected; andprotect the motor from overload consistent with the second operating parameters if the second operating mode is selected.

11. The method of claim 11, further including allowing for timed deceleration of the motor between the first operating mode being selected and a subsequent selection of the second operating mode, if the first operating mode operates the motor at a higher rate of speed than the second operating mode.