FIELD OF THE INVENTION

The present invention generally relates to electrical protection technology for domestic utilities, particularly to safe, efficient and secured externally controllable domestic board breaker system. Advantageously, the domestic board breaker with available protection system replaces electro-thermo-mechanical era of domestic supply board system.

BACKGROUND ART

Around the world, domestic utilities are most prone for various electrical hazards and electrical fires. The electromechanical era of electrical protection technology is replaced by numerical protection systems in Extra High Voltage (EHV), High Voltage (HV), Medium Voltage (MV) and Air Circuit Breakers (ACB) in Low Voltage (LV) distribution boards. By introducing the numerical protection technology, the power system became safer to humans and their properties. This is made possible by the availability of a properly designed circuit breaker to control and monitor power flow in the above mentioned voltage level areas.

Domestic distribution board is a component of an electricity supply system that divides an electrical power feed into subsidiary circuits, while providing a protective system or circuit breaker for each circuit in a common enclosure. Such circuit breakers and protection systems are not known to be used in domestic utility areas. The absence of latest protection technology is the major reasons for fatal and fire hazards every day that is observed around the world.

According to prior arts, in domestic supply switch boards, Miniature Circuit Breakers (MCB) is used for controlling each of the electrical circuits. However, these MCBs could be switched l ON and OFF by manual operation only. External/remote operation of MCB is not possible. Therefore, monitoring and protection devices could not electrically control or operate MCB from local/remote.

Further, the MCBs are capable of automatically opening its electrical circuit due to overheating during over load and short circuit. The MCB is used for Over Current (OC) and Short Circuit (SC) faults and Earth Leakage Circuit Breaker (ELCB) is used for ground faults.

Disadvantages of the prior art are:

• MCB carries the fault current and over heat the circuit continuously until the current becomes 5% to 20% above the rating of the MCB. The overheating followed by the short circuit is considered as the reason for electrical fires around the world.

• MCB has only single break and produce arc during normal ON and OFF switching with full load.

• As different rated MCBs that includes 5A, 10A, 15A, 20A, and 30A are used in the same distribution board it may cause least load circuit to be connected to a higher rated MCB and never trips on over load until short circuit associated with fire hazard.

• MCB never trips on ground fault.

• ELCB never trips on over load fault or short circuit fault.

• Testing and commissioning of MCB and ELCB with respect to connected load is not possible and such commissioning/maintenance test is not a standard practice.

US5574653 discloses a switchboard having a mains power input circuit (A,N) and a plurality of output circuits and including a central processing unit (CPU) for controlling a plurality of controllable circuit breakers. The breakers are controllable by the CPU. Sensing means provide the CPU with instantaneous voltage and current magnitudes to enable the CPU to determine power consumed by the output circuits.

US8213144 discloses a method and apparatus for providing protection against arc flash during maintenance on a low voltage power circuit including a circuit breaker having a specified trip function for responding to a fault is provided.

US5053735 relates to a remotely operated circuit breaker comprising a handle which is selectively positioned at one of three operating positions: a handle off position into which the handle is manually positioned to forcibly open the electrical contacts in the circuit breaker; a handle auto position into which the handle is positioned manually so that the electrical contacts are driven to normally open and close by a control mechanism which in turn is controlled by an electromagnetic driving unit response to a remote control voltage applied thereto; and a trip position into which the handle is automatically positioned by the control mechanism and a forcible overcurrent protecting unit to and the electrical contacts are opened rapidly when an overcurrent as well as a short-circuit current flows through the electrical contacts.

US6139327 discloses a remotely controlled simulated linear circuit breaker capable of being set and reset remotely, and manually operated.

US4636760 discloses a low voltage circuit breaker with remote switching function characterized by an insulating housing containing manually actuator for opening and closing separable contacts and a remotely controlled solenoid for opening the contacts, and the solenoid means being spring biased in the closed contact position only when the manually actuator is in the closed contact position.

2172/DELNP/2009 discloses a system comprising one or more breaker open/closure control units each of which receives the system voltage or the electric quantity of the main circuit current, a state quantity of the breaker, and a breaker open or closure command signal, and makes a control to open or close the breaker at a desired phase of the system voltage or the main circuit current and a display operation unit which is connected through a communication network and performs display operation for operation monitoring.

Accordingly, there exists a need for safe, efficient and secured externally controllable domestic board breaker to work with available protection system that replaces electro- thermo-mechanical era of domestic supply board system.

OBJECTS OF THE INVENTION

One or more of the problems of the conventional prior art may be overcome by various embodiments of the system of the present invention.

It is the primary object of the present invention to provide domestic board breaker system which is a standalone system and purely electro- mechanical device.

It is another object of the present invention to provide efficient and reliable protection to the domestic utilities in association with available protection technology. It is another object of the present invention to provide safe, efficient and secured externally controllable domestic board breaker to work with available protection system that replaces electro-thermo-mechanical era of domestic supply board system.

It is another object of the present invention to provide domestic board breaker system which is externally/remotely controllable by electronic devices or numerical protection relays as in Extra High Voltage (EHV), High Voltage (HV), Medium Voltage (MV) and Air Circuit Breakers (ACB) in Low Voltage (LV) switch boards.

It is another object of the present invention, wherein fixed and moving contacts of the domestic board breaker system facilitates double breaking facility which thereby eliminates production of arcs between the fixed and moving contacts even above full load rated current.

It is another object of the present invention, wherein the domestic board breaker system is uniformly rated for 30A at 230 Volts 50 Hz, said settings would be decided by associated numerical protection relay with respect to the connected load in each circuit.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention, there is provided a domestic board breaker system, comprising:

one or more fixed contacts;

moving contact for closing and opening of the main circuit;

spring return mechanism of the moving contact;

closing mechanism;

non-movable closing magnetic coil with movable plunger; opening mechanism;

non-movable opening magnetic coil with movable plunger;

normally closed (NC) status contact;

normally open (NO) status contact;

one or more push buttons for actuating local closing and opening operation; and one or more insulated knobs for actuating manual closing and opening operation, wherein the normally closed (NC) status contact is arranged between the non-movable opening magnetic coil and movable plunger for electrical closing operation and removing control supply after closing action,

wherein the normally open (NO) status contact is arranged between the non-movable closing magnetic coil and movable plunger for electrical opening operation and removing control supply after opening action,

wherein when the domestic board breaker system is in open status, control supply connected to terminals is switched ON, and

wherein on receiving close or open command by respective terminals from remote, actuates closing or opening mechanism respectively.

It is another aspect of the present invention, whereiri forward movement of the contact simultaneously touches the fixed contacts and deliver power from bus bar to the external load/line during its actual usage.

It is another aspect of the present invention, wherein the fixed and moving contacts facilitate double breaking facility which thereby eliminates production of arcs between the fixed and moving contacts even above full load rated current. It is another aspect of the present invention, wherein one of the insulated knobs is fixed to the closing mechanism for manual closing operation and the other insulated knob is fixed to the opening mechanism for manual opening operation.

It is another aspect of the present invention, wherein the non-movable closing magnetic coil with movable plunger is used for closing action through a link between the movable plunger and closing mechanism.

It is another aspect of the present invention, wherein the non-movable opening magnetic coil with movable plunger is used for opening action through a link between the opening mechanism and movable plunger.

It is another aspect of the present invention, wherein the domestic board breaker system includes LED indicators for indicating status of closing and opening of the domestic board breaker.

It is another aspect of the present invention, wherein the domestic board breaker system includes provisions to display as closed and open, said one of the provisions is mechanically attached to the opening mechanism, said other provision is mechanically attached to the link.

It is another aspect of the present invention, wherein the domestic board breaker system includes an emergency push button which by pressing, electrical closure of the domestic board breaker is disabled from remote as well as local, thereby ensuring for safety during maintenance in the associated electric circuit. It is another aspect of the present invention, wherein by pull of the insulated knob fixed to the closing mechanism makes all the actions of push on the push button, and completes the manual close operation.

It is another aspect of the present invention, wherein by pull of the insulated knob fixed to the opening mechanism makes all the actions of push on the push button and completes the manual opening operation.

It is another aspect of the present invention, wherein by a push on the push button, the non- movable closing magnetic coil energizes with voltage and its movable plunger pulls the closing mechanism, wherein movement of the closing mechanism actuates/pushes the spring return mechanism and completes the closing action by firmly attaching the movable contact over the surfaces of fixed contacts.

It is another aspect of the present invention, wherein by a push on the push button, the non- movable opening magnetic coil energizes with voltage and its movable plunger pulls the opening mechanism, wherein movement of the opening mechanism unblocks/unlatches the closing mechanism and spring pressure in the spring return mechanism rapidly detaches the movable contact from the surfaces of fixed contacts and completes the opening action.

It is another aspect of the present invention, wherein the domestic board breaker system is remotely controllable by electronic devices or numerical protection relays as in Extra High Voltage (EHV), High Voltage (HV), Medium Voltage (MV) and Air Circuit Breakers (ACB) in Low Voltage (LV) switch boards. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 : illustrates single pole Miniature Circuit Breaker (MCB) according to the prior art. Figure 2: illustrates two pole Miniature Circuit Breaker (MCB) according to the prior art. Figure 3: illustrates Earth Leakage Circuit Breaker (ELCB) according to the prior art.

Figure 4: illustrates construction diagram of domestic board breaker system according to the present invention.

Figure 5: illustrates circuit diagram of interconnection between the components of domestic board breaker system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention as herein described relates to domestic board breaker system which is a standalone system and purely electro-mechanical device.

Construction:

Referring to Figures 4 and 5, the domestic board breaker system comprising of one or more fixed contacts [1 , 2]; moving contact [3] for closing and opening of the main circuit; spring return mechanism [6] of the moving contact [3]; closing mechanism [7]; non-movable closing magnetic coil [12] with movable plunger [13]; opening mechanism [16]; non-movable opening magnetic coil [20] with movable plunger [21]. The fixed [1, 2] and moving [3] contacts are installed on insulated plates [4 and 5] respectively. The fixed contact [1] has provision for connecting the mains power and the fixed contact [2] has provision for connecting the external load/line. The moving contact [3] is arranged in parallel to the fixed contacts [1 , 2]. A straight and forward movement of the contact [3] simultaneously touches the fixed contacts [1 , 2] and deliver power from bus bar to the external load/line during its actual usage. The insulated plate [5] with moving contact [3] is placed in parallel to the insulated plate [4] in the spring return mechanism [6] assembly. The closing mechanism [7] is held by a metallic socket [8] fixed to a metallic base plate [9], said closing mechanism [7] is preferably made of cast iron. The closing mechanism [7] is provided with a metallic stopper [10] fixed to the metallic base plate [9]. A metallic spring [1 1] is installed between the closing mechanism [7] and metallic stopper [10]. The metallic spring [1 1] gets compressed by the closing mechanism [7] during its open status and released during its closing action. The non-movable closing magnetic coil [12] with movable plunger [13] which is installed on the metallic base plate [9] is used for closing action through a link [14] between the movable plunger [13] and closing mechanism [7]. The system is provided with an insulated knob [15] fixed to the closing mechanism [7] for manual closing operation of the system.

The opening mechanism [16] is held by a metallic socket [17] fixed to the metallic base plate [9], said opening mechanism [16] is preferably made of cast iron. The opening mechanism [16] is provided with a metallic stopper [18] fixed to the metallic base plate [9]. A metallic spring [19] is installed between the opening mechanism [16] and metallic stopper [18]. The non-movable opening magnetic coil [20] with movable plunger [21] which is installed on the metallic base plate [9] is used for opening action through a link [22] between the opening mechanism [16] and movable plunger [21]. The system is provided with an insulated knob [23] fixed to the opening mechanism [16] for manual opening operation.

To make the electrical closing operation efficient and removing control supply after closing action, a normally closed (NC) status contact [24] is arranged between the non-movable opening magnetic coil [20] and movable plunger [21] on insulated plates fixed to it. The normally closed contact [24] is a micro-switch or limit switch which is controlled by a single end spring attached lever. Under normal status, the contact will remain open and the free end of the lever will be projected out. A push or by means of sliding force on the lever, the open contact will change its status to closed condition. The normally closed contact [24] is fixed behind and on the body of non-movable opening magnetic coil [20] in such a way that the extended tail end of the movable plunger [21] will give sliding force on the lever of micro- switch/limit-switch and the contact [24] will remain closed during open status and open during closed status of the system.

To make the electrical opening operation efficient and removing control supply after opening action, a normally open (NO) status contact [25] is arranged between the non-movable closing magnetic coil [12] and movable plunger [13] on insulated plates fixed to it. The normally open (NO) status contact [25] is a micro-switch or limit switch controlled by a single end spring attached lever. Under normal status, the contact will remain open and the free end of the lever will be projected out. A push or by means of sliding force on the lever, the open contact will change its status to closed condition. The normally open contact [25] is fixed behind and on the body of non-movable closing magnetic coil [12] in such a way that the extended tail end of the movable plunger [13] will give sliding force on the lever of micro-switch/limit-switch and the contact [25] will remain close during closed status and open during open status of the system.

The system is further provided with one or more push buttons [26, 27] and one or more LED indicators [29, 30] assembled on a vertical metallic plate [34] fixed to the metallic base plate [9] to be visualized from the front of the domestic board, said push buttons [26, 27] for the operation of closing and opening respectively and LED indicators [29, 30] for indicating status of opening and closing respectively of the domestic board breaker. Further, the system has provisions [32, 33] to display as closed and open, said provision [32] is mechanically attached to the opening mechanism [16], said provision [33] is mechanically attached to the link [22]. The vertical plate [34] with hole [35] of pre-defined diameter is adjusted in such a way that the provisions [32, 33] could be visualized one at a time with respect to the actual mechanical status position of the domestic board breaker.

An emergency push button [36] is fixed to the vertical plate [34] for the purpose of emergency tripping and further close block until manual reset of it. The emergency push button [36] has normally opened (NO) and normally closed (NC) contacts for wiring. Both contacts operate simultaneously during push and resetting. The normally closed (NC) contact is wired in series with the closing coil and the normally open contact is wired in parallel to the opening push button. The pushing of emergency push button [36] will open the domestic board breaker system and isolate further closing facility until a manual reset of the button [36]. That is, by pressing the emergency push button [36], electrical closure of the domestic board breaker is disabled from remote as well as local thereby ensuring for safety during maintenance in the associated electric circuit.

The fixed [1 , 2] and moving [3] contacts facilitate double breaking facility which thereby eliminates production of arcs between the fixed and moving contacts even above full load rated current. The domestic board breaker is uniformly rated for 30A at 230 Volts 50 Hz. The settings will be decided by associated protection relay with respect to the connected load in each circuit. Wiring:

The electrical wiring is through a set of terminal block [28] installed on the metallic base plate [9] and the wiring is connected through one or more terminals [28.1 , 28.2, 28.3, 28.4, 28.5, 28.6, and 28.7]. The power supply to the domestic board breaker could be of various means. In one aspect, the control supply is a single phase 230 Volts 50 Hertz controlled by 1 Amps glass fuse assembly [31] connected through wire [37] vide the terminal block [28.1 , 28.2]. Wire [39] from the terminal block [28.2] is connected to the normally closed (NC) status contact [24] and normally open (NO) status contact [25]. The connectivity of the normally closed (NC) status contact [24] to the LED indicator [30] and the closing push button [26] are by wire [40] through the terminal block [28.4]. The connectivity of the normally open (NO) status contact [25] to the LED indicator [29], opening push button [27] and the emergency push button [36] are by wire [41] through the terminal block [28.6]. The closing push button [26] is connected to the emergency push button [36] by wire [43] through the terminal block [28.5], The emergency push button [36] is connected to the non-movable closing magnetic coil [12] by wire [44]. Wire [45] from the terminal block [28.3] is connected to the closed LED indicator [30], non-movable closing magnetic coil [12], non- movable opening magnetic coil [20], and open LED indicator [29].

The control supply is a single phase 230 Volts 50 Hertz controlled by 1 Amps glass fuse assembly [31 ]. The same domestic service supply or from uninterruptible power supply (UPS) or from solar system of the above rating could be used as the domestic board breaker auxiliary power supply. The domestic board breaker is capable of manufacturing with various DC control supply such as 24V, 30V, 1 10V, and 220V. The closing magnetic coil, opening magnetic coil, and LED indicators must be rated for the selected control supply voltage. Working:

Referring to Figure 5, consider the domestic board breaker system in open status. The control supply connected to the terminals [28.1 and 28.3] is switched on. With control supply healthy, the LED indicator [30] glows and indicates that the domestic board breaker system is in open status. The mechanical indicator [33] shows open through the hole [35].

Local close operation:

By a push on the push button [26], the non-movable closing magnetic coil [12] energizes with voltage and its movable plunger [13] pulls the closing mechanism [7]. The movement of the closing mechanism [7] actuates/pushes the spring return mechanism [6] and completes the closing action by firmly attaching the moving contact [3] on the surfaces of the fixed contacts [1 and 2]. Simultaneously the opening mechanism [16] moves and blocks return of the closing mechanism [7] and latched in position. The movement of the opening mechanism [16] opens the normally closed ( C) status contact [24] and isolates supply to the closing magnetic coil [12] and LED indicator [29]. The pulling action of the non-movable closing magnetic coil [12] and movable plunger [13] makes closure of the normally open (NO) status contact [25] assembled on it. The closing of the normally open (NO) status contact [25] connects supply to the LED indicator [30] and its glow as well as the provision [32] through hole [35] indicates that the domestic board breaker system is in closed status.

Remote close operation:

The terminals [28.4 and 28.5] are dedicated connection points to receive close command from remote. An extended wiring from potential free contact of a remote device or relay to the terminals [28.4 and 28.5] is required. The rest actions are similar to the push or automatic closure of the potential free remote contact. On receiving the command, the non-movable closing magnetic coil [12] energizes with voltage and its movable plunger [13] pulls the closing mechanism [7]. The movement of the closing mechanism [7] actuates/pushes the spring return mechanism [6] and completes the closing action by firmly the moving contact [3] on the surfaces of the fixed contacts [1 and 2]. Simultaneously the opening mechanism [16] moves and blocks return of the closing mechanism [7] and latched in position. The movement of the opening mechanism [16] opens the normally closed (NC) status contact [24] and isolates supply to the non-movable closing magnetic coil [12] and LED indicator[29]. The pulling action of the non-movable closing magnetic coil [12] and movable plunger [13] makes closure of the normally open (NO) status contact [25] assembled on it. The closing of the normally open (NO) status contact [25] connects supply to the LED indicator [30] and its glow as well as the provision [32] through hole [35] indicates that the domestic board breaker system is in closed status.

Manual close operation:

A pull of the insulated knob [15] fixed to the closing mechanism [7] makes all the actions of push on the push button [26], and completes the close operation.

Local open operation:

By a push on the push button [27], the non-movable opening magnetic coil [20] energizes with voltage and its movable plunger [2t] pulls the opening mechanism [16]. The movement of the opening mechanism [16] unblocks/unlatches the closing mechanism [7] and spring pressure in the spring return mechanism [6] rapidly detaches the moving contact [3] from the surfaces of the fixed contacts [1 and 2] by disengaging the closing mechanism [7]. Simultaneously the closing mechanism [7] moves and returns to its initial position. The movement of the closing mechanism [7] opens the normally open (NO) status contact [25] and isolates supply to the non-movable opening magnetic coil [20] and LED indicator [30], The pulling action of the non-movable opening magnetic coil [20] and movable plunger [21 ] makes closure of the normally closed (NC) status contact [24] assembled on it. The closing of normally closed (NC) status contact [24] connects supply to the LED indicator [29] and its glow as well as the provision [33] through the hole [35] indicates that the domestic board breaker system is in open status.

Remote open operation:

The terminals [28.6 and 28.7] are dedicated connection point to receive open or trip command from remote. An extended wiring from potential free contact of a remote device or relay to the terminals [28.6 and 28.7] is required. The rest actions are similar to the push or automatic closure of the potential free remote contact. On receiving the command, the non- movable opening magnetic coil [20] energizes with voltage and its movable plunger [21] pulls the opening mechanism [16]. The movement of the opening mechanism [16] unblocks/unlatches the closing mechanism [7] and spring pressure in the spring return mechanism [6] rapidly detaches the moving contact [3] from the surfaces of the fixed contacts [1 and 2] by disengaging the closing mechanism [7]. Simultaneously the closing mechanism [7] moves and returns to its initial position. The movement of the closing mechanism [7] opens the normally open (NO) status contact [25] and isolates supply to the non-movable opening magnetic coil [20] and LED indicator [30]. The pulling action of the non-movable opening magnetic coil [20] and movable plunger [21] makes closure of the normally closed (NC) status contact [24] assembled on it. The closing of normally closed (NC) status contact [24] connects supply to the LED indicator [29] and its glow as well as the provision [33] through the hole [35] indicates that the domestic board breaker system is in open status.

Manual open operation:

A pull of the insulated knob [23] fixed to the opening mechanism [16] makes all the actions of push on the push button [27] and completes the opening operation.