Claims:1. A system to operate and control an electronic motor starter, wherein said system comprising
at least one protection relay;
at least one Star relay; and
at least one Start relay;
wherein each of said relays operated by a controller unit, wherein said controller unit configured with a timer module to provide preconfigured Star Delta delay, and a transit timer module;
wherein, when said start relay turned ON, normally open (NO) contact terminals of said start relay gets connected to a common terminal of said start relay to operate said motor in star configuration;
wherein, after said timer module and subsequently said timer module elapses, said controller unit adapted to turn OFF said start relay, said NO contact terminals gets disconnected from said common terminal and a normally closed (NC) contact terminals gets connected with said common terminal, to switch said motor in delta configuration.

2. The system as claimed in claim 1, wherein said start relay adapted to provide dual functionality of turning ON motor automatically and to switch said system to said Delta configuration.

3. The system as claimed in claim 1, wherein said NC contact terminals of said Start relay is connected to a coil of said Delta contactor and said NO contact terminals of said Start relay is connected to the Start Button.

4. The system as claimed in claim 1, wherein mode of said motor starter operated through a display interface connected to said controller unit, or remotely through an electronic device through a Short Message Service(SMS) or Interactive Voice Recognition System(IVRS) or GPRS or other serial data mode.

5. The system as claimed in claim 4, interfaced with a Global System for Mobile Communication (GSM) module to provide remote operation of said motor starter to a user.

6. A method for operating an electronic motor starter, comprising:
actuating, by automatic mode or manual mode, a start relay along with a protection relay and a star relay;
enabling a connection of normally open (NO) contact terminals with a common terminal of said start relay, for operating said motor in star configuration;
triggering, by a controller unit, a timer module with Star Delta delay, wherein upon lapse of said Star Delta delay, triggering, by means of said controller unit, a transit timer module;
turning OFF said start relay after lapse of said transit timer module;
disconnecting, by said controller unit, said NO contact terminals from said common terminal of Start relay and thereby enabling connection of normally closed (NC) contact terminals with said common terminal of Start relay, for operating said motor in delta configuration.
, Description:TECHNICAL FIELD OF THE INVENTION

[001] The present subject matter described herein, in general, relates to electronic motor controller, and more specifically to automatic motor starter systems, preferably used in irrigation.

BACKGROUND OF THE INVENTION

[002] Motors used for irrigation are usually located at the river banks along with motor starter. These areas are perilous due to difficult terrains and various animals present in the vicinity. Hence, there is a need for a device capable of providing remote access to control the motor operation. Also, most parts of India face a huge problem of load shedding.

[003] Electricity is distributed at predefined schedules to different areas. Farmer has to go to the motor site to turn ON the motor manually. This involves huge risk to farmer’s life especially if electricity resumes in the middle of the night. Also Induction motors draw very high current at start when started directly on line. The heavy current drawn by the motor results in disturbance of voltage on supply line. To limit the starting current surge, induction motors are started at reduced voltage and then have full supply voltage reconnected when they run up to near rotated speed.

[004] There are two methods of reducing the starting voltage: (1) Start Delta Starter
(2) Auto Transformer Starter. The automatic Star Delta Starter system consists of a rocker switch (i.e., single-pole, single-throw (SPST) switch), a Protection relay (SPST), a Star relay (SPST), a Delta relay (SPST), 3 contactors (Main, Star and Delta contactor), a Start button, a Stop button and a microcontroller unit as shown in figure 1. The rocker switch is used to select the operating mode (i.e. Automatic or Manual) of the system. It is connected across the Start button as shown in figure 1. Star and Delta relays are connected in series with Star and Delta contactor coil respectively to control the configuration of the motor starter. Microcontroller unit can be used to operate the relays and provides protection to the motor in case of any failure in the system.
[005] In Automatic mode, the rocker switch bypasses the start button externally. If the system is healthy, microcontroller unit turns ON the Protection relay and the Star relay. Thus motor operates automatically in Star configuration since Start button was bypassed. Microcontroller unit then turns OFF the Star relay and turns ON Delta relay after the configured Star Delta time to operate the motor in Delta configuration. In Manual mode, the rocker switch is in open state so in order to start the motor, external Start button placed across rocker switch has to be pressed. The start button starts the motor in star configuration and microcontroller unit then switches the motor to Delta configuration after the preconfigured Star Delta time.

[006] However, this design requires an additional rocker switch for mode configuration and operation. Also, such a design is not capable of providing remote operation of the motor starter.

[007] For some existing start delta starter reference is made to US5142213A which relates to an open start delta starter to limit the current surge during open transition of starter by adjusting the phase relationship between the induced motor winding voltage and the line voltage .Automatic or remote operations of the motor cannot be done using these starter

[008] Reference is also made to WO2015056271 which describes a system to improve the design of power contactors used in the start delta system. It uses a pair of three pole delta and main contactors , and a single pole contactor for supplying AC power to star position and delta position and a timer control with a logic circuit for controlling AC power supply switching operation for star position and delta position

[009] However, the prior arts fails to teach a solution for remotely and automatically controlling the motor starter system and particularly, the star delta configured motor starter. Accordingly, there is a need for a Star Delta motor starter system along with providing automatic functionality as well as remote access.

SUMMARY OF THE INVENTION

[0010] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[0011] An object of the present invention is to provide a system that can be easily interfaced with an Open Star Delta Starter configuration to operate motor in Automatic or Manual mode.

[0012] Another object of the present invention is to provide a control circuit design of automatic star delta starter which can be easily interfaced with Global System for Mobile Communication (GSM) module to provide remote access of the motor starter to the user.

[0013] Accordingly to one aspect, the present invention provides a system for an electronic motor starter, wherein said system comprising: at least one protection relay; at least one Star relay; and at least one Start relay; wherein each of said relays operated by a controller unit, wherein said controller unit configured with a timer module to provide preconfigured Star Delta delay, and a transit timer module; wherein, when said start relay turned ON, normally open (NO) contact terminals of said start relay gets connected to a common terminal of said start relay to operate said motor in star configuration; wherein, after said timer module and subsequently said timer module elapses, said controller unit adapted to turn OFF said start relay, said NO contact terminals gets disconnected from said common terminal and a normally closed (NC) contact terminals gets connected with said common terminal, to switch said motor in delta configuration.

[0014] In another aspect, the present invention a method for operating an electronic motor starter, comprising:
• actuating, by automatic mode or manual mode, a start relay along with a protection relay and a star relay;
• enabling a connection of normally open (NO) contact terminals with a common terminal of said start relay, for operating said motor in star configuration;
• triggering, by a controller unit, a timer module with Star Delta delay, wherein upon lapse of said Star Delta delay, triggering, by means of said controller unit, a transit timer module;
• turning OFF said start relay after lapse of said transit timer module;
• disconnecting, by said controller unit, said NO contact terminals from said common terminal of Start relay and thereby enabling connection of normally closed (NC) contact terminals with said common terminal of Start relay, for operating said motor in delta configuration

[0015] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0016] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0017] Figure 1 illustrates the control circuit for conventional Automatic Star delta Motor Starter, according to prior art.

[0018] Figure 2 illustrates the control circuit of the proposed Automatic Start Delta Motor Starter for the present invention, according to one embodiment of the present invention.

[0019] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0020] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0021] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0022] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0023] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0024] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0025] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0026] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0027] In one implementation, the present system consists of a Protection relay (SPST), a Star relay (SPST), a Start relay (SPDT), a microcontroller unit, three contactors, a Start switch, a Stop switch and auxiliary contacts of Main and Star contactor, as shown in figure 2. The Start relay can be used to provide dual functionality, i.e. to turn ON motor automatically and to switch the system to Delta configuration. The NC contact of the Start relay is connected to the coil of Delta contactor and the NO contact of the Start relay is connected to the Start Button as shown in figure 2. The settings (e.g. operation mode, star delta time, protection delay, and the like) of the system can be changed through a display interface connected to the controller (microcontroller) unit or remotely through electronic device (for e.g. mobile phone) via Short Message Service (SMS) or Interactive Voice Recognition System (IVRS) or GPRS or any other serial data mode.

[0028] In the implementation, the present invention provides a control circuit of automatic star delta configuration of motor starter having an additional single relay, i.e., the start relay which can placed in parallel to the start button is used to achieve two functionalities:
1. Automatically starting the motor: When Start relay is turned ON, NO terminal of Start relay gets connected to its common terminal. Thus, Star coil gets energized when Star relay is turned ON which in turn energizes Main coil through its auxiliary contact and system operates in Star configuration
2. Switching the system to Delta configuration: When Start relay is turned OFF, NC terminal of Start relay gets connected to its common terminal. Thus Delta coil gets energized through NC contact of Start relay and motor operates in delta configuration

[0029] In one implementation, in automatic mode, the start relay will be turned ON along with the Protection and Star relay. When start relay is turned ON, it’s NO contact gets connected to the common terminal of the Start relay which in turn operates the motor in Star configuration. The auxiliary contact (NC) of Star contactor placed in series with the coil of Delta contactor prevents the operation of Delta contactor. Thus, system operates in Star configuration. Microcontroller unit will then start an internal timer to provide preconfigured Star Delta delay. When the Star Delta time gets elapsed, microcontroller unit turns OFF the Star relay and starts a transit timer. After the transit time, the microcontroller unit turns OFF the Start relay. When Start relay will be turned OFF, it’s NO contact gets disconnected from the common terminal and NC contact gets connected to the common terminal. Thus motor will switch in Delta configuration.

[0030] In the implementation, the Automatic mode of operation turns the motor ON when healthy power supply is available. This eliminates the task of turning ON motor manually each time power resumes. Also this design can be very easily interfaced with a GSM module to provide remote access of motor starter giving remote access of motor to the farmer. This design is auto-compatible with DOL starter, Semi-Automatic Star Delta starter and a Fully Automatic Star Delta starter.

[0031] In another implementation, in manual mode, the microcontroller unit configured to turn ON Protection and Star relay. Microcontroller unit then keeps sensing the feedback signals from the motor to detect the Start button press. If start button press is detected then motor turns ON the Start relay. Thus, NO of Start relay gets connected to common terminal of Start relay. Motor now operates in Star configuration. Microcontroller unit then starts a timer to provide Star Delta delay. When the Star Delta time gets elapsed, microcontroller unit turns OFF the Star relay and starts a transit timer. After the transit time, the microcontroller unit turns OFF the Start relay. When Start relay is turned OFF, it’s NO contact gets disconnected from the common terminal and NC contact gets connected to the common terminal. Thus motor operates in Delta configuration.

[0032] In both the implementation, a GSM module can be easily interfaced with the microcontroller unit. This GSM module communicates with the mobile phone of the operator and conveys the message to the microcontroller unit. In order to operate or change the settings of the motor starter, a specific command can be given from mobile phone via SMS or IVRS or GPRS. The GSM module receives these messages and passes them to the microcontroller unit via a serial interface. The microcontroller unit then decodes the message and performs the corresponding action. Thus, the motor starter can be controlled remotely by connecting a GSM module.

[0033] The design of the automatic star delta motor starter system is auto-compatible with different starters (that includes but not limited to DOL starter, semi-automatic star delta starter and a fully automatic star delta starter). Each starter will have an external start and stop switch to operate the motor manually. Thus, it becomes necessary to sense the feedback from the motor starter to know the current state of the starter. Therefore, in view of this, in one implementation, the present invention provides a common interface for feedback detection for each starter. Thus, this design can be used with any starter without providing the information about the starter to the microcontroller unit. Hence, a universal automatic electronic motor starter can be designed using this system.

[0034] Some of the noteworthy features of the present invention are as follows:
• The present invention is related to the first method of reducing voltage, i.e. Star Delta starter along with providing automatic functionality as well as remote access.
• In the present invention, single relay (start relay) is used to automatically start the motor and switch the system to delta configuration.
• The present invention provides an automatic star delta starter system which has configurable Open transition time which helps in adjusting the system as per different motor ratings and can help to an extent to reduce the transition surge during closing of Delta contactor after open transition state.
• The present invention provides an automatic starter system which can be easily interfaced with the GSM module to provide remote operation of the motor starter to the user.
• The system of the present invention provides configurable star delta timer. This helps in connecting different motors to the system.
• The system of the present invention is auto-compatible with different starters. This design can be used with any starter without providing the information about the starter to the microcontroller unit.

[0035] Some of the non-limiting advantages of the present invention are as follows:
• The automatic start delta motor starter system of the present invention can automatically start the motor when power resumes which is very useful where load shedding is major problem.
• Single relay (start relay ) of the present invention can automatically start the motor and switch the system to delta configuration as compared to the conventional systems that use an external switch to turn ON motor automatically and a separate relay(NO contacts ) which is used to switch over the system to delta state.
• The present invention presents a universal automatic motor starter system which can operate automatically as well as can be controlled remotely.

[0036] Although system and method for operating an electronic motor starter of the present invention have been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementation of the system and method for operating an electronic motor starter.