DESC:TECHNICAL FIELD
[002] The present disclosure in general relates to the FLP controller (drive control system in flame proof enclosure) for battery operated locomotive. More particularly, the present invention relates to the unique type of control panel consisting of DC to DC Chopper, switch gear components viz., MCCB, Main Contactor, ELR, housed in FLP enclosure for control of tractions motors of battery operated mine locomotive.
BACK GROUND
[003] Underground mines, especially the coal mines, are the place where concentrations of flammable gases, vapors, or dusts present more in common. Use of electrical equipments like Battery operated Locomotives, Load Haul Dumpers, and Side Discharge Loaders and also apparatus like signaling or lighting will always come with the risk of electrically-initiated explosions of flammable gas and dust.
The equipments that must be installed in such locations are need to be specially designed for flameproof characteristics and tested at certified laboratories and approved by regulatory authorities like DGMS (in India).
The battery operated Locomotives to be used for hauling of coal in underground coal mines will be equipped with DC series traction motors as a prime mover. The motors will be operated through a control panel which will incorporate a motor speed controller module, protective devices and other accessories housed in FLP enclosure.
SUMMARY
[004] Before the present system in one implementation, operation & speed control of the traction motors in Locomotives was achieved with a drum controller. The controller is in the form of a rotating drum having insulated and interconnected segments in the form
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of strips which makes contact with the fixed points. Across this fixed points starting resistances and reversing contacts are connected for speed reversal of motors to operate locomotive in other direction.
For reversing the direction of motor, it is required to change either the direction of armature or field. It is preferred to reverse the armature current and the same is achieved also through the drum controller.
The conventional drum controller system are having disadvantages of frequent wear & tear of fixed and moving contacts, generation of sparks, carbon deposition, manual effort for lever operation, frequent maintenance, servicing & replacement of spares. The above disadvantages lead to reduction in productivity of the machine.
[005] In present implementation, a control method by use of a PWM based DC chopper with safety interlocks has been incorporated and housed in the FLP enclosure for smooth control of DC series motors & enhancing the operator comfort. Thus increase in productivity of the system.
BRIEF DESCRIPTION OF DRAWINGS
[006] The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating of the present subject matter, an example of construction of the present subject matter is provided as figures; however, the present subject matter is not limited to the specific method disclosed in the document and the figures.
[007] The present subject matter is described detail with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer various features of the present subject matter.
[008] Figure 1 illustrates the FLP controller for locomotive & method of control, in accordance with an embodiment of the present subject matter.
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[009] Figure 2 illustrates the FLP controller for Locomotive, in accordance with an embodiment of the present subject matter.
[100] Figure 3 illustrates method for controlling the locomotive by using the FLP controller, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[011]Some embodiments of the present disclosure, illustrating all its features, will now be discussed in detail. It must be also be noted that as used herein and in the appended claims, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. Although any device similar or equivalent to those described herein can be used in practice or testing of embodiments of the present disclosure. Although any controller and method using the components / accessories/devices ,similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, a controller and method using for the operation of locomotive are now described.
[012] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments for controller and method using the components / accessories/devices for the operation of locomotive. However, one of ordinary skill in the art will readily recognize that the present disclosure for controller and method using the components / accessories/devices for the operation of locomotive is not intended to be limited to the embodiments described, but is to be accorded the widest scope consistent with the principles and features described herein.
[013] In one embodiment, FLP controller with unique methods for the operation of locomotive is disclosed. Referring to Figure 1, A FLP controller is illustrated. In the figure 1 The major components of the system are, battery bank, battery isolator (OFF Load type) MCCB (1), DC-DC Chopper (2), main Contactor (3), F/R Contactor (4), Key switch (5), timer (6), protective devices (fuses), relays (8), forward/reverse (F/R) selector Switch (9), DC-DC Converters/ Inverter (10), POT box (throttle) (11) , Connecting terminals with insulated stud arrangements, entry for FLP cables through
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double compression glands, measuring devices such as DC shunt, voltmeter, ammeter and LED indicators (15), head lamps, audio visual alarm, foot pedal switch, service brake switch, emergency brake switch, input & output connections of loco controller are provided with terminal studs & insulators in the respective chambers through Plug & socket and glands. All the components/devices are interconnected with cables through Plug & socket and gland arrangements.
[014] Referring now to figure 2, the block diagram shown represents, FLP controller with unique methods for the operation of locomotive. Further the figure 2 consist of 1. MCCB, 2. DC-DC Chopper, 3.Main Contactor, 4. F/R Contactor, 5. Key switch, 6.Timer, 7.protective devices (fuses/MCB), 8.Relays, 9.Forward/Reverse (F/R) selector Switch, 10. DC-DC Converter and Inverter, 11. POT box (throttle), 12.Connecting terminals with insulated stud arrangements, 13.entry for FLP cables through Plug & socket and gland arrangements, 14. Measuring devices such as DC shunt, Voltmeter, Ammeter and 15.LED indicators. The above components are interconnected through cables with end terminals.
[015] Referring now to Figure 3 the methods for FLP controller of a locomotives disclosed. In the method at Step1 The locomotive is provided with the battery bank (192V DC) as a source of power. The battery cells are arranged in a crates and the crates are housed in a container/ box with suitable plug & socket arrangements for input/output (charging/Loading). The output is connected to a battery isolator.
[016] Upon step 1 at step 2 Battery isolator receives Electrical power from battery bank. Through an offload isolator switch & protective fuse arrangement the battery power is supplied to the FLP controller via FT-7 cable and plug & socket arrangement.
[017] Upon step 2 at step 3, FLP controller receives power from battery isolator through plug & socket arrangement. The main contactor is connected in series with battery positive (B+) terminal via a MCCB and suitable HRC fuse to disconnect the power when the system in OFF condition.
Subsequently the output of the main contactor is connected to the chopper (motor controller module). The negative terminal of the battery is connected to the chopper
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through a polarity protection diode to avoid wrong connection. The Panel meters (Voltmeter & Ammeter) & control circuit components of the FLP controller are powered up by switching ON the MCCB.
[018] Upon step 2 at step 3 & 4The chopper (motor controller module) receives the power from the main contractor. The main contractor is operated based on the following safety interlocks available on the system.
1. Key switch interlock with Pre start Alarm -.
Once the key switch is ON, the prestart alarm will start to work up to 15 sec. during this time the loco cannot be operated. Controller will not generate any output.
2. Service brake switch.
In service brake applied condition, the limit switch is in open condition and the control circuit is open. Service brake is need to be released to make the control circuit closed.
3. Emergency brake switch
In Emergency brake applied condition, the limit switch is in open condition. Emergency brake is need to be released to make the control circuit closed.
4. Foot pedal switch
It is also known as "Dead man Switch", Foot pedal switch will be always in open condition & need to be pressed and hold to close the switch contacts. Foot pedal switch is to be pressed & hold for normal operation of the locomotive. On the event of removal of foot from pedal the machine comes to halt.
5. Pot Box with Micro switch (Limit switch)
POT box with micro switch will be in normally Open condition and potentiometer is at zero position. When the knob of the pot box is rotated & hold, the limit switch closes. Wiper on the pot varies & proportionate signal is applied to the chopper. Subsequently chopper provides the output and the same is feed to the motor. When the hand from the
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knob is removed, knob will come back to its home position automatically by its spring return mechanism & limit switch opens which results in halting the machine by switching OFF the main contractor.
6. Earth Leakage relay (ELR).
ELR is provided as a safety feature to protect the system as well as human being against leakage current. If the battery leakage current is more than the set value, ELR trips the control circuit & there by the halting the machine. Until the fault is cleared the ELR will not reset on its own. After rectifying the fault, ELR need to be reset for normal operation.
Operation of: The relay senses the DC Earth leakage current for the equipment by sensing Resistance between Positive- Negative Terminals of DC System & earth. Thus leakage current if any will be dependent on the resistance value between respective terminals, Higher the resistance , lower is the leakage current & vice versa. Lower resistance results in to more leakage current resulting in damage to equipment and loss of life. Earth leakage relay senses leakage current through Resistor Bridge & energizes relay when Resistance value goes out of the range selected on the dial. The Relays are provided with user settable (0-10Sec) time delay.
The status of the above interlocks are indicated through the LED indicators provided inside the FLP controller.
[019] Upon step 3& 4, at step In step 5, the direction of the Locomotive travel is selected through the Forward/Reverse (F/R) selector switch. The output of the F/R selector switch is connected to FWD/REV contactor. Depending upon selection direction, corresponding change over occurs in the FWD/REV contactor. Simultaneously the respective Head lamp, Tail lamp & Audio visual Alarm (AVA) will turn ON. On Forward selection Front head lamp & rear tail lamp glow and vice-versa if reverse direction selected.
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[020] In step 6 & 7, Once the conditions of the interlocks are satisfied, the main contactor will close in turn the voltage (192V) of the battery bank is connected with a motor controller (chopper) module. The motor controller used here is a low side chopper having parallel IGBT array for control. It is rated for 192V, 800A & analog current limit can be set with digital shutdown backup. A parallel diode array provides freewheeling of inductive energy to the motor. The gates of the IGBTs are pulsed at 10 KHz by PWM pulse generator. The microprocessor of the chopper reads input from throttle (The Pot input varies from 0 to 4.9K ohms. Minimum resistance of the pot will leads to minimum speed and if the resistance is increasing , accordingly the speed of the locomotive will increase.) and accordingly the duty (width of the PWM signal) of the gate pulse is determined. 0% duty is corresponding to zero current and 100% duty is equal to the maximum current. Surface mounted 12VDC fan is providing cooling for the chopper. 2 nos. LED indicators are provided on the chopper (built in - RED & GREEN) for indication of ready status (GREEN) colour indicates healthy & tripped/faulty/ condition with RED indication. The chopper needs to be reset for RED indication. The chopper has been provided with suitable fuse protection externally.
[021] In step 8&9 , The traction DC series motors (2 No) are connected in series connection. The armature of the motors are connected between chopper module and forward/reverse contactor. The field windings of the motors connected across forward/reverse contactor. The direction of rotation of the motor can be reversed by using the forward reverse contactor through field reversal. This contactor will be controlled by the FWD/REV selector switch.
[022] In case of any emergency, by pressing the emergency stop push button on the FLP controller, the MCCB can be tripped. When the MCCB is tripped the total power will be cut off to the FLP controller. The power to the FLP controller will be resumed by resetting the MCCB manually.
The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced
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are not to be construed as critical, required, or essential features of any or all of the embodiments.
While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.
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We Claim:
1. FLP drive control panel for underground mine locomotives having MCCB (1) , DC-DC Chopper (2), main Contactor (3), F/R Contactor (4), Key switch (5), timer (6), protective devices (fuses), relays (8), forward/reverse (F/R) selector Switch (9), DC-DC Converters/ Inverter (10), POT box (throttle) (11) , Connecting terminals with insulated stud arrangements, entry for FLP cables through double compression glands, measuring devices such as DC shunt, voltmeter, ammeter and LED indicators (15),Other external electrical apparatus/aggregates like head lamps, audio visual alarm, foot pedal switch, service brake switch, emergency brake switch, input & output connections of loco controller are provided with terminal studs & insulators in the respective chambers through Plug & socket and glands; all the components/devices are interconnected with cables through Plug & socket and gland arrangements.
2. FLP drive control panel for underground mine locomotives as claimed in claim 1 wherein the locomotive is provided with the battery bank (192V DC) as a source of power external to the control panel and housed in a metal crate with suitable plug & socket arrangements for input/output (charging/Loading) and the output is connected to a battery isolator (through an isolator switch & protective fuse arrangement).
3. FLP drive control panel for underground mine locomotives as claimed in claim 2 wherein FLP controller receives power to MCCB (is used for ON/OFF of power supply) from battery isolator through plug & socket arrangement. The main contactor is connected to battery positive (B+) terminal via a MCCB and suitable HRC fuse to protect against short circuit. The output of the main contactor is connected to the chopper (motor controller module), the negative terminal of the battery is connected to the chopper through a polarity protection diode to avoid reverse polarity. The main contactor is operated based on the functioning of safety interlocks available on the system. Safety interlocks includes, Key switch interlock with pre-start alarm, service brake limit switch, emergency brake limit switch, foot pedal switch, pot box with micro switch (limit switch), earth leakage relay (ELR). The Panel meters (Voltmeter & Ammeter) & control circuit components of the FLP controller are powered up by MCCB and control MCBs.
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4. FLP drive control panel for underground mine locomotives as claimed in claim 3 wherein once the key switch is ON, the prestart alarm will start to provide audio-visual alarm up to 15 sec (is settable up to 60 Sec). During this time the loco movement cannot be achieved due to cut off of control circuit for chopper ( as a safety measure during pre-start period). Control circuit will be operative after pre-start period. The chopper will not generate any output due to absence of reference voltage as the service brake and Emergency brakes are in applied condition(the limit switches in open condition in control circuit); the brakes are need to be released to make the control circuit closed. Foot pedal switch receives control supply from the control panel.
5. FLP drive control panel for underground mine locomotives as claimed in claim 4 wherein foot pedal switch is always in open condition & need to be pressed and hold to close the switch contacts for normal operation of the locomotive, on the event of removal of foot from pedal, control circuit will become open. Normally POT box with micro switch will be in open condition and potentiometer is at zero position; when the knob of the pot box is held & rotated, the limit switch closes, wiper on the potentiometer varies & proportionate signal is applied to the chopper, subsequently chopper provides proportionate output to the motor; when the hand from the knob is removed, the knob will come back to its home position automatically by its spring return mechanism & micro switch opens & resulting in cut off the control supply and switching OFF the main contactor.
6. FLP drive control panel for underground mine locomotives as claimed in claim 5 wherein An earth leakage relay (ELR) is provided as a safety feature to protect the system as well as human being against leakage current; If the battery leakage current is more than the set value, ELR trips the control circuit & cut off the control supply to the main contactor and remains trip until the fault is cleared ( ELR will not reset on its own) after rectifying the fault, ELR need to be reset for normal operation. The status of the interlocks are indicated through the LED indicators provided inside the FLP controller.
7. FLP drive control panel for underground mine locomotives as claimed in claim 6 wherein the direction of the Locomotive travel is selected through the Forward/Reverse (F/R)
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selector switch; the output of the F/R selector switch is connected to FWD/REV contactor, depending upon selection direction, corresponding change over occurs in the FWD/REV contactor; the armature of the motors are connected between chopper module and forward/reverse contactor; the direction of rotation of the motor are reversed by field reversal (the field windings of the motors connected across forward/reverse contactor;) simultaneously the respective Head lamp, Tail lamp & Audio visual Alarm (AVA) turn ON, on forward selection front head lamp & rear tail lamp glow and vice-versa if reverse direction selected.
8. FLP drive control panel for underground mine locomotives as claimed in claim 7 wherein once the conditions of the interlocks are satisfied, the main contactor will close, in turn required voltage ( up to192V) is applied through throttle to the motor controller (chopper) module; the chopper is provided with a fan for cooling; LED indicators are provided on the chopper, Green and Red LEDs indicate Ready and Fault status respectively. The chopper needs to be reset to clear faulty status, the chopper has been provided with suitable external fuse protection for gate pulses. In case of any emergency, by pressing the emergency stop push button on the FLP controller, the MCCB can be tripped; when the MCCB is tripped the total power is cut off to the FLP controller; The power to the FLP controller is resumed by resetting the MCCB manually. Panel will be ready for operation after reset.
Jaya Bhatnagar
Attorney for the applicants

,CLAIMS:We Claim:
1. FLP drive control panel for underground mine locomotives having MCCB (1) , DC-DC Chopper (2), main Contactor (3), F/R Contactor (4), Key switch (5), timer (6), protective devices (fuses), relays (8), forward/reverse (F/R) selector Switch (9), DC-DC Converters/ Inverter (10), POT box (throttle) (11) , Connecting terminals with insulated stud arrangements, entry for FLP cables through double compression glands, measuring devices such as DC shunt, voltmeter, ammeter and LED indicators (15),Other external electrical apparatus/aggregates like head lamps, audio visual alarm, foot pedal switch, service brake switch, emergency brake switch, input & output connections of loco controller are provided with terminal studs & insulators in the respective chambers through Plug & socket and glands; all the components/devices are interconnected with cables through Plug & socket and gland arrangements.
2. FLP drive control panel for underground mine locomotives as claimed in claim 1 wherein the locomotive is provided with the battery bank (192V DC) as a source of power external to the control panel and housed in a metal crate with suitable plug & socket arrangements for input/output (charging/Loading) and the output is connected to a battery isolator (through an isolator switch & protective fuse arrangement).
3. FLP drive control panel for underground mine locomotives as claimed in claim 2 wherein FLP controller receives power to MCCB (is used for ON/OFF of power supply) from battery isolator through plug & socket arrangement. The main contactor is connected to battery positive (B+) terminal via a MCCB and suitable HRC fuse to protect against short circuit. The output of the main contactor is connected to the chopper (motor controller module), the negative terminal of the battery is connected to the chopper through a polarity protection diode to avoid reverse polarity. The main contactor is operated based on the functioning of safety interlocks available on the system. Safety interlocks includes, Key switch interlock with pre-start alarm, service brake limit switch, emergency brake limit switch, foot pedal switch, pot box with micro switch (limit switch), earth leakage relay (ELR). The Panel meters (Voltmeter & Ammeter) & control circuit components of the FLP controller are powered up by MCCB and control MCBs.
4. FLP drive control panel for underground mine locomotives as claimed in claim 3 wherein once the key switch is ON, the prestart alarm will start to provide audio-visual alarm up to 15 sec (is settable up to 60 Sec). During this time the loco movement cannot be achieved due to cut off of control circuit for chopper ( as a safety measure during pre-start period). Control circuit will be operative after pre-start period. The chopper will not generate any output due to absence of reference voltage as the service brake and Emergency brakes are in applied condition(the limit switches in open condition in control circuit); the brakes are need to be released to make the control circuit closed. Foot pedal switch receives control supply from the control panel.
5. FLP drive control panel for underground mine locomotives as claimed in claim 4 wherein foot pedal switch is always in open condition & need to be pressed and hold to close the switch contacts for normal operation of the locomotive, on the event of removal of foot from pedal, control circuit will become open. Normally POT box with micro switch will be in open condition and potentiometer is at zero position; when the knob of the pot box is held & rotated, the limit switch closes, wiper on the potentiometer varies & proportionate signal is applied to the chopper, subsequently chopper provides proportionate output to the motor; when the hand from the knob is removed, the knob will come back to its home position automatically by its spring return mechanism & micro switch opens & resulting in cut off the control supply and switching OFF the main contactor.
6. FLP drive control panel for underground mine locomotives as claimed in claim 5 wherein An earth leakage relay (ELR) is provided as a safety feature to protect the system as well as human being against leakage current; If the battery leakage current is more than the set value, ELR trips the control circuit & cut off the control supply to the main contactor and remains trip until the fault is cleared ( ELR will not reset on its own) after rectifying the fault, ELR need to be reset for normal operation. The status of the interlocks are indicated through the LED indicators provided inside the FLP controller.

7. FLP drive control panel for underground mine locomotives as claimed in claim 6 wherein the direction of the Locomotive travel is selected through the Forward/Reverse (F/R) selector switch; the output of the F/R selector switch is connected to FWD/REV contactor, depending upon selection direction, corresponding change over occurs in the FWD/REV contactor; the armature of the motors are connected between chopper module and forward/reverse contactor; the direction of rotation of the motor are reversed by field reversal (the field windings of the motors connected across forward/reverse contactor;) simultaneously the respective Head lamp, Tail lamp & Audio visual Alarm (AVA) turn ON, on forward selection front head lamp & rear tail lamp glow and vice-versa if reverse direction selected.
8. FLP drive control panel for underground mine locomotives as claimed in claim 7 wherein once the conditions of the interlocks are satisfied, the main contactor will close, in turn required voltage ( up to192V) is applied through throttle to the motor controller (chopper) module; the chopper is provided with a fan for cooling; LED indicators are provided on the chopper, Green and Red LEDs indicate Ready and Fault status respectively. The chopper needs to be reset to clear faulty status, the chopper has been provided with suitable external fuse protection for gate pulses. In case of any emergency, by pressing the emergency stop push button on the FLP controller, the MCCB can be tripped; when the MCCB is tripped the total power is cut off to the FLP controller; The power to the FLP controller is resumed by resetting the MCCB manually. Panel will be ready for operation after reset.