Title of Invention

DYNAMIC BRAKING SYSTEM FOR D.C. SERIES TRACTION MACHINES (ORE TRANSFER CAR) TRAVEL MECHANISM

Abstract

The present invention relates to a dynamic braking system for DC series traction machines adapted to be driven over the trolley lines existing, said system comprising: a wheeled vehicle including at least first and second wheels, a drive system supported on said vehicle, said drive system including a DC series traction motor coupled to said first wheel; a second DC series traction motor coupled to said second wheel; a controller characterized by a circuitry for a control system comprising a circuitry which provides stopping / braking of the car.

Full Text

DYNAMIC BRAKING SYSTEM FOR D.C SERIES TRACTION MACHINES (ORE TRANSFER CAR) TRAVEL MECHANISM. The present invention relates to a control drive system for a DC electric traction vehicle operating between two points and, more particularly, to a dynamic braking system for DC electric traction vehicles (ore transfer car) travel mechanism in the event of power failure. BACKGROUND ART In mining operations it is common to employ a shuttle car for transporting the material being mined, for example, mineral, from the work area to an unloading area where the material is unloaded onto a conveyor belt or onto cars for transporting out of the mine. Such cars are electrically operated with the electrical energy being supplied thereto from a source at the unload ng point via a cable or trolley lines which moves toward the work area, and returns to the unloading point. In DC electric motor powered vehicles, it is common practice to employ the drive motor to brake the vehicle by reversing the direction of torque of the motor This type of braking is known as plugging Electric industrial vehicles which are presently designed such that when running at full speed, a direction selector may be moved to select an opposite direction without releasing the accelerator In such vehicles an electric control circuit overrides the accelerator demand and provides a substantially constant level of braking torque until the motor speed has dropped to near zero. Previously proposed control systems regulated braking torque by maintaining a constant level of field flux or by maintaining a constant level of armature current Both of these methods have known defects. Ore transfer cars are used to transport iron ore, sinter and additives to blast furnaces hopper in Bhilai steel plant. It has a travel mechanism, pocket mechanism to discharge raw material in 2 different furnace material bunkers. For not allowing the car to roll down after coming to a halt, the pneumatic brakes are applied. Pneumatic brakes can't be applied if the car is in motion. In the event of power failure ore transfer car used to travel down as long it has kinetic energy, which causes collision between two cars, accidents, damage to the trolley line and was very unsafe for the personal working around. SUMMARY OF THE INVENTION: Therefore according to the invention the car is provided with a dynamic braking system for DC series traction machines adapted to be driven over the trolley lines existing, said system comprising: a wheeled vehicle including at least first and second wheels, and a drive system supported on said vehicle, said drive system including a DC series traction motor coupled to said first wheel; a second DC series traction motor coupled to said second wheel; a controller characterized by a circuitry for a control system comprising a circuitry which provides stopping / braking of the car. According to the invention the car is also provided a control system carried by a vehicle having a plurality of means which continuously engage the ground to thereby move the vehicle, said vehicle having a DC traction motor cooperable with at least some of said ground engaging means to cause movement thereof and carrying steering means to move said vehicle in a selected path, said control system comprising a circuitry which provides stopping / braking of the car in the event of power failure. As per another aspect of the present invention there is provided a mechanism to dissipate the kinetic energy of the car in the event of power failure. 3 As per an exemplary embodiment of the present invention the said controller includes an operator interface coupled to said controller to allow an operator of the vehicle to provide command signals to said controller. Yet another aspect of the present invention is to provide a circuit whose spares are easily available and easily arranged / assembled. The fourth object of the present invention is to provide a circuitry having minimal accessories. The fifth object of the present invention is to provide a simple reliable and low cost circuitry. The sixth object of the present invention is to provide a circuit, which is free from any maintenance requirements. The seventh object of the present invention is to provide an electronic circuitry, which can last long and handle DC power fluctuations. As per another exemplary object of the present invention is to stop the travel of the car by means of retardation without the application of pneumatic brakes at the earliest to ensure safety to the people working around. Moreover to avoid collision / accidents of two cars in the event of power loss while traveling in opposite direction and to avoid any damage to the cars and trolley line caused due to derailments etc. Another exemplary embodiment provides a breaking system wherein the dynamic breaking contactors are permanently "ON". It gets triggered in the event 4 of power loss or the operator can apply emergency switch to drop dynamic breaking contactors to stop the car. the dynamic breaking contactors gets triggered in the event of power loss or the operator can apply emergency switch to drop dynamic breaking contactors to stop the car. These together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is an illustrated preferred embodiment of the invention. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 is a circuit diagram showing the old scheme for the ore transfer car circuit. FIG. 2 is a circuit diagram showing the modified scheme for the ore transfer car circuit with dynamic breaking arrangement as per the present invention. FIG. 3 is a circuit diagram showing the old control scheme for the ore transfer car circuit. FIG. 4 is a circuit diagram showing the modified control scheme for the ore transfer car circuit with dynamic breaking arrangement as per the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Invention relates to electric systems of vehicles furnished with dc motors, particularly to regenerative braking devices of traction electric motors of cars. Proposed device contains two parallel groups of traction motors. Armature 5 windings of traction electric motors in each group are connected through diode into series circuit with field windings, anode reactors, two steps of brake resistor, in brake resistor circuits. Starting and braking of traction electric motors in effected by means of regulators of current in field windings and voltage in armature windings In DC electric motor powered vehicles, it is common practice to employ the drive motor to brake the vehicle by reversing the direction of torque of the motor This type of braking is known as dynamic braking or plugging Electric industrial vehicles are presently designed such that when running at full speed, a direction selector may be moved to select an opposite direction without releasing the accelerator In such vehicles an electric control circuit overrides the accelerator demand and provides a substantially constant level of braking torque until the motor speed has dropped to near zero. Previously proposed control systems regulated braking torque by maintaining a constant level of field flux or by maintaining a constant level of armature current Both of these methods have known defects, a typical example of which is an effect called "cogging " Cogging is recognizable as one or more bumps or lurches of the vehicle which normally occur toward the end of the braking interval as a result of variations in braking torque It has been found that cogging is much more pronounced when the vehicle is switched into a braking mode at a low rather than a high speed It has also been found that cogging is more pronounced in those vehicles using electric motors with a high K, motor constant, which motors produce more counter EMF per ampere of field current Previous attempts to alleviate cogging by selection of motors having low K v motor constants have been inefficient aid ineffectual other attempts to reduce cogging by providing controlled acceleration have proven impractical because excessive response times produce sluggish operation of the vehicle. 6 Normally the car travels in forward and reverse direction, to bring it to a halt reversing plugging is done. But in case of power loss from the source, the reversing plugging will not work. In order to bring it to a halt, the kinetic energy of the car is required to be dissipated to bring the car to stand still. There was no scheme available to bring it to stand still in the event of power failure. Hence by putting d1,d2,d3,d4,(diodes), dynamic braking contactors (DBC's) with dynamic breaking resistances (DBR's), the direction of the current generated by the Eb (back electro motive force) is getting applied automatically to bring the car to retard stop. Whenever the car travels the back EMF will be in opposite direction to that of applied voltage. The max back EMF is theoretically around 95% of the applied voltage. For causing the smooth normal operation the dynamic breaking contactors are permanently "ON". It gets triggered in the event of power loss or the operator can apply emergency switch to drop dynamic breaking contactors to stop the car. Some of the Salient features of the present invention: A. Safety to the individuals working around. B. No collision can take place if two cars travel in opposite direction and there a loss of power. C. No damage to the cars, trolley lines and its brackets. Benefits: A. Created an atmosphere of confidence building amongst the operators. B. Accident free car. 7 Advantages: A. It can be applied in any system, which works on D.C. traction with D.C. series motors. B. The scheme can be made workable for any number of motors operating by expanding the scheme. Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. 8 List of components: 1. FC1, FC2, RC1, RC2 - DIRECTION POWER CONTACTORS. 2. L1, L2 - LINE CONTACTORS. 3. KS - POWER KNIFE SWITCH. 4. OCR1, OCR2 - OVER CURRENT RELAYS. 5. DBR - DYNAMIC BRAKING RESISTANCE. 6. D1,D2,D3,D4 - POWER DIOBES 7. DBC1, DBC2 - DYNAMIC BRAKING CONTACTORS. 8. M1, M2 - DC SERIES MOTORS. (TRACTION). 9. SEF1, SEF2 - SERIES FILE OF MOTOR 1 AND MOTOR 2. 10. PR - PERMANENT RESISTANCE. 11.F1, F2- POWER FUSES. 12. OPTG BAY 1 AND OPTG BAY 2 - CONTROL POSTS. 13. NVR - NOVO; T RELAY. 14.1/L LS1 AND I/L LS2- INTERLOCKING LUMID SWITCH. 15.ER- ECONOMY RESISTANCE FOR DYNAMIC BRAKING CONTACTORS. THE ABOVE SYSTEM WORKS ON DC SOURCE. SUPPLIED FROM SUBSTATION. 9 We Claim:- 1. A dynamic braking system for DC series traction machines adapted to be driven over the trolley lines existing, said system comprising: a wheeled vehicle including at least first and second wheels, a drive system supported on said vehicle, said drive system including a DC i series traction motor coupled to said first wheel; a second DC series traction motor coupled to said second wheel; a controller characterized by a circuitry for a control system comprising a circuitry which provides stopping / braking of the car. 2. A dynamic braking system for a DC series traction machines as claimed in claim 1, wherein the circuitry is operable in the event of power failure. 3. The dynamic braking system as claimed in claim 1, wherein said controller includes an operator interface coupled to said controller to allow an operator of the vehicle to provide command signals to said controller. 4. The dynamic braking system as claimed in claim 1, wherein said controller provides at least speed and direction references to said circuit. 5. A dynamic braking system for DC series traction machines as claimed in claim 2, wherein the circuitry comprises of diodes (d1,d2,d3,d4), dynamic breaking contactors (DBC's) with dynamic breaking resistances (DBR's). 6. A dynamic braking system as claimed in claim 5, wherein the dynamic breaking contactors are permanently "ON". It gets triggered in the event of power loss or the operator can apply emergency switch to drop dynamic breaking contactors to stop the car. 10 7. A dynamic braking system as claimed in claim 5, wherein the dynamic breaking contactors gets triggered in the event of power loss or the operator can apply emergency switch to drop dynamic breaking contactors to stop tne car. 8. A dynamic braking system for DC series traction machines, substantially such as herein described with particular reference to the accompanying drawings. The present invention relates to a dynamic braking system for DC series traction machines adapted to be driven over the trolley lines existing, said system comprising: a wheeled vehicle including at least first and second wheels, a drive system supported on said vehicle, said drive system including a DC i series traction motor coupled to said first wheel; a second DC series traction motor coupled to said second wheel; a controller characterized by a circuitry for a control system comprising a circuitry which provides stopping / braking of the car.

Documents:

00878-kol-2007-abstract.pdf

00878-kol-2007-claims.pdf

00878-kol-2007-correspondence others.pdf

00878-kol-2007-description complete.pdf

00878-kol-2007-drawings.pdf

00878-kol-2007-form 1.pdf

00878-kol-2007-form 2.pdf

00878-kol-2007-form 3.pdf

878-KOL-2007-(13-10-2014)-ABSTRACT.pdf

878-KOL-2007-(13-10-2014)-CLAIMS.pdf

878-KOL-2007-(13-10-2014)-CORRESPONDENCE.pdf

878-KOL-2007-(13-10-2014)-DESCRIPTION (COMPLETE).pdf

878-KOL-2007-(13-10-2014)-DRAWINGS.pdf

878-KOL-2007-(13-10-2014)-FORM-1.pdf

878-KOL-2007-(13-10-2014)-FORM-2.pdf

878-KOL-2007-(13-10-2014)-OTHERS.pdf

878-KOL-2007-(13-10-2014)-PA.pdf

878-kol-2007-form 18.pdf

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