A soft start device for a railway locomotive headlamp

Abstract

The utility model relates to railway locomotive technical field especially a railway locomotive headlamp soft start device, including power, PCB board and headlamp, PCB board is provided with delay circuit, and delay circuit includes first resistance, second resistance and delay capacitor in series, and the positive pole of power is electrically connected with the one end of first resistance away from second resistance, and the negative pole of power is electrically connected with the one end of delay capacitor away from second resistance, and the positive pole of power is provided with switch with first resistance, the one end of headlamp is electrically connected with the positive pole of power, and the other end is electrically connected with the negative pole of power through field effect tube, and the drain electrode of field effect tube is electrically connected with headlamp, and the source electrode of field effect tube is electrically connected with the negative pole of power, and the gate of field effect tube is electrically connected with delay capacitor. The utility model is completely conducted when the resistance increases to reach stable after the headlamp filament temperature rises, avoids the headlamp damage and shortens the life because of the large current impact, and effectively improves the service life of railway locomotive headlamp.

Description

Technical Field

[0001] This utility model relates to the field of railway locomotive technology, and in particular to a soft-start device for railway locomotive headlights. Background Technology

[0002] Railway locomotive headlights provide illumination for locomotives operating at night or in low visibility conditions, helping drivers clearly observe road conditions ahead and ensuring driving safety. Headlights are typically located at the front and rear top of the locomotive, resembling searchlights, and provide strong illumination at night or in low visibility conditions such as heavy rain or dense fog, making it easier for the driver to see. Railway locomotive headlights used in local factories and mines generally use tungsten bulbs as the light source, typically with a power of around 800 to 1000 watts and an operating voltage of DC 110V. Because the tungsten filament of the bulb is cold at startup and has very low resistance, a large inrush current is generated at startup, making the headlights prone to damage. Utility Model Content

[0003] To address the aforementioned issues, this invention provides a soft-start device for railway locomotive headlights. This device fully conducts light when the resistance of the headlight filament increases and stabilizes after the filament temperature rises, thus preventing damage to the headlight and shortening its lifespan due to high current surges and effectively improving the service life of railway locomotive headlights.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A soft-start device for railway locomotive headlights includes a power supply, a PCB board, and a headlight. The PCB board is provided with a delay circuit, which includes a first resistor, a second resistor and a delay capacitor connected in series. The positive terminal of the power supply is electrically connected to the end of the first resistor away from the second resistor, and the negative terminal of the power supply is electrically connected to the end of the delay capacitor away from the second resistor. A switch is provided between the positive terminal of the power supply and the first resistor. One end of the headlight is electrically connected to the positive terminal of the power supply, and the other end is electrically connected to the negative terminal of the power supply through a field-effect transistor. The drain of the field-effect transistor is electrically connected to the headlight, the source of the field-effect transistor is electrically connected to the negative terminal of the power supply, and the gate of the field-effect transistor is electrically connected to the end of the delay capacitor closest to the second resistor.

[0005] Furthermore, the PCB board is provided with a discharge circuit, which includes a third resistor and a diode. One end of the third resistor is electrically connected to the headlight, and the other end is electrically connected to the diode. The end of the diode away from the third resistor is electrically connected to the end of the delay capacitor close to the second resistor.

[0006] Furthermore, the PCB board is provided with a protection circuit, which includes a Zener diode and a fourth resistor, wherein the Zener diode and the fourth resistor are connected in parallel between the gate of the field-effect transistor and the negative terminal of the power supply.

[0007] Furthermore, the PCB board is provided with a diode, the two ends of which are electrically connected to the drain of the field-effect transistor and the source of the field-effect transistor, respectively.

[0008] Furthermore, current-limiting resistors are respectively provided at both ends of the diode.

[0009] Furthermore, the PCB board is mounted on the mounting base, and the PCB board is provided with wiring terminals.

[0010] Furthermore, the PCB board is provided with through mounting holes around its perimeter, and bolts are provided in the mounting holes. The bolts slide through the mounting holes and are threadedly connected to the mounting base.

[0011] Furthermore, the bolt is fitted with a nylon washer, and the two sides of the nylon washer abut against the PCB board and the mounting base, respectively.

[0012] The beneficial effects of this utility model are: When the switch is closed, the power supply charges the delay capacitor through the first and second resistors connected in series. The voltage across the delay capacitor rises slowly over time, and the gate voltage of the MOSFET rises accordingly. As the gate voltage of the MOSFET increases, the MOSFET gradually turns on. Initially, under the limitation of the delay capacitor, only part of the MOSFET is turned on, which is equivalent to a large resistor connected in series in the headlight circuit. This results in a very small current flowing through the tungsten filament of the headlight. The tungsten filament heats up under the influence of the current, and its temperature gradually increases. At the same time, the resistance also gradually increases, and the conduction degree of the MOSFET gradually increases until it is fully turned on. At this point, the temperature of the tungsten filament has stabilized and reached normal operating conditions. This method can limit the large current surge generated at the moment of headlight startup due to the low temperature and low resistance of the tungsten filament caused by thermal inertia; it avoids damage to the headlight caused by the large current surge and shortens its lifespan, effectively improving the service life of railway locomotive headlights. When the headlight switch is turned off, the charge on the delay capacitor is rapidly discharged through the third resistor, diode, and field-effect transistor, causing the voltage on the delay capacitor to drop rapidly, preparing for the next start of the headlights. Attached Figure Description

[0013] Figure 1 This is a circuit diagram of a preferred embodiment of the railway locomotive headlight soft-start device of this utility model.

[0014] Figure 2 This is a schematic diagram of the mounting base structure of a railway locomotive headlight soft starter device according to a preferred embodiment of the present invention.

[0015] In the diagram, 1-power supply, 2-PCB board, 21-first resistor, 22-second resistor, 23-first capacitor, 24-switch, 3-headlight, 31-MOSFET, 41-third resistor, 42-diode, 51-Zenith diode, 52-fourth resistor, 6-diode, 61-current limiting resistor, 7-mounting base, 71-terminal block, 72-bolt, 73-nylon pad. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] Please also see Figure 1 and Figure 2 The preferred embodiment of this utility model discloses a soft-start device for railway locomotive headlights, comprising a power supply 1, a PCB board 2, and a headlight 3. The PCB board 2 is equipped with a delay circuit, a discharge circuit, and a protection circuit. The power supply 1 is a 110V DC power supply.

[0020] The delay circuit includes a first resistor 21, a second resistor 22 and a delay capacitor 23 connected in series. The positive terminal of the power supply 1 is electrically connected to the end of the first resistor 21 away from the second resistor 22, and the negative terminal of the power supply 1 is electrically connected to the end of the delay capacitor 23 away from the second resistor 22. A switch 24 is provided between the positive terminal of the power supply 1 and the first resistor 21. One end of the headlight 3 is electrically connected to the positive terminal of the power supply 1, and the other end is electrically connected to the negative terminal of the power supply 1 through the field-effect transistor 31. The drain of the field-effect transistor 31 is electrically connected to the headlight 3, the source of the field-effect transistor 31 is electrically connected to the negative terminal of the power supply 1, and the gate of the field-effect transistor 31 is electrically connected to the end of the delay capacitor 23 near the second resistor 22.

[0021] When switch 24 is closed, power supply 1 charges delay capacitor 23 through the first resistor 21 and the second resistor 22 connected in series. The voltage across delay capacitor 23 slowly increases over time, and the gate voltage of field-effect transistor 31 increases accordingly. As the gate voltage of field-effect transistor 31 increases, field-effect transistor 31 gradually turns on. At the beginning of power-on, under the limitation of delay capacitor 23, field-effect transistor 31 is only partially turned on, which is equivalent to a large resistor connected in series in the circuit of headlight 3, so that the current flowing through the tungsten filament of headlight 3 is very small. The tungsten filament of headlight 3 heats up under the action of current, and the temperature gradually increases. At the same time, the resistance also gradually increases, and the degree of conduction of field-effect transistor 31 gradually increases. Finally, it is fully turned on, and the temperature of the tungsten filament has stabilized and reached the normal operating state.

[0022] In this embodiment, the RC delay circuit composed of the first resistor 21, the second resistor 22 and the delay capacitor 23 controls the field effect transistor 31 to conduct slowly and delay, which can limit the large current surge generated by the headlight 3 at the moment of start-up due to the low temperature and low resistance of the tungsten filament due to thermal inertia; avoid damage to the headlight 3 caused by the large current surge and shorten its lifespan, and effectively improve the service life of the railway locomotive headlight 3.

[0023] The discharge circuit includes a third resistor 41 and a diode 42. One end of the third resistor 41 is electrically connected to the headlight 3, and the other end is electrically connected to the diode 42. The end of the diode 42 away from the third resistor 41 is electrically connected to the end of the delay capacitor 23 close to the second resistor 22.

[0024] When the headlight switch 24 is turned off, the charge on the delay capacitor 23 is rapidly discharged through the third resistor 41, diode 42, and field-effect transistor 31, causing the voltage on the delay capacitor 23 to drop rapidly, preparing for the next start of the headlight. At the same time, the addition of a reverse diode 42 to the delay capacitor 23 enables the charge on the delay capacitor 23 to be quickly discharged when the switch is turned off, so as to avoid the loss of the delay function due to the accumulation of charge in the delay capacitor during frequent switching.

[0025] The protection circuit includes a Zener diode 51 and a fourth resistor 52, which are connected in parallel between the gate of the field-effect transistor 31 and the negative terminal of the power supply 1. The Zener diode 51 and the fourth resistor 52 constitute the gate protection circuit of the field-effect transistor 31.

[0026] In this embodiment, the PCB board 2 is provided with a diode 6, and the two ends of the diode 6 are electrically connected to the drain of the field-effect transistor 31 and the source of the field-effect transistor 31, respectively.

[0027] A current-limiting resistor 61 is set at each of the two ends of diode 6.

[0028] After the field-effect transistor 31 is turned on normally, the voltage across its terminals is very low and does not reach the starting voltage of the diode 6. When the field-effect transistor 31 or other components are damaged, causing the field-effect transistor 31 to fail to turn on normally, the power supply 1 drives the headlight 3 and the current-limiting resistor 61 to illuminate, thus indicating the fault.

[0029] like Figure 2 As shown, PCB board 2 is mounted on mounting base 7, and PCB board 2 is provided with wiring terminals 71. In this embodiment, wiring terminals 71 are used to connect power supply 1, headlight 3 and switch 24, so that power supply 1, headlight 3 and switch 24 are electrically connected to PCB board.

[0030] The PCB board 2 has through mounting holes around its perimeter. Each mounting hole is fitted with a bolt 72, which slides through the mounting hole and is threadedly connected to the mounting base 7.

[0031] Bolt 72 is fitted with nylon pad 73, and the two sides of nylon pad 73 abut against PCB board 2 and mounting base 7 respectively.

[0032] By mounting the PCB board 2 onto the mounting base 7 for fixing and heat dissipation, the provided nylon pad 73 allows for a gap between the PCB board 2 and the mounting base 7, thereby improving the heat dissipation effect.

[0033] The usage process of the soft starter for railway locomotive headlights in this embodiment is as follows: When switch 24 is closed, power supply 1 charges delay capacitor 23 through the first resistor 21 and the second resistor 22 connected in series. The voltage across delay capacitor 23 slowly increases over time, and the gate voltage of field-effect transistor 31 increases accordingly. As the gate voltage of field-effect transistor 31 increases, field-effect transistor 31 gradually turns on. At the beginning of power-on, under the limitation of delay capacitor 23, field-effect transistor 31 is only partially turned on, which is equivalent to a large resistor connected in series in the circuit of headlight 3, so that the current flowing through the tungsten filament of headlight 3 is very small. The tungsten filament of headlight 3 heats up under the action of current, and the temperature gradually increases. At the same time, the resistance also gradually increases, and the degree of conduction of field-effect transistor 31 gradually increases. Finally, it is fully turned on, and the temperature of the tungsten filament has stabilized and reached the normal operating state.

[0034] When the headlight switch 24 is turned off, the charge on the delay capacitor 23 is rapidly discharged through the third resistor 41, diode 42, and field-effect transistor 31, causing the voltage on the delay capacitor 23 to drop rapidly, preparing for the next start of the headlights.

Claims

1. A soft-start device for railway locomotive headlights, characterized in that, Includes power supply (1), PCB board (2) and headlight (3). The PCB board (2) is provided with a delay circuit, which includes a first resistor (21), a second resistor (22) and a delay capacitor (23) connected in series. The positive terminal of the power supply (1) is electrically connected to the end of the first resistor (21) away from the second resistor (22), and the negative terminal of the power supply (1) is electrically connected to the end of the delay capacitor (23) away from the second resistor (22). A switch (24) is provided between the positive terminal of the power supply (1) and the first resistor (21). One end of the headlight (3) is electrically connected to the positive terminal of the power supply (1), and the other end is electrically connected to the negative terminal of the power supply (1) through a field-effect transistor (31). The drain of the field-effect transistor (31) is electrically connected to the headlight (3), the source of the field-effect transistor (31) is electrically connected to the negative terminal of the power supply (1), and the gate of the field-effect transistor (31) is electrically connected to the end of the delay capacitor (23) near the second resistor (22).

2. The soft-start device for railway locomotive headlights according to claim 1, characterized in that: The PCB board (2) is provided with a discharge circuit, which includes a third resistor (41) and a diode (42). One end of the third resistor (41) is electrically connected to the headlight (3), and the other end is electrically connected to the diode (42). The end of the diode (42) away from the third resistor (41) is electrically connected to the end of the delay capacitor (23) close to the second resistor (22).

3. The soft-start device for railway locomotive headlights according to claim 1, characterized in that: The PCB board (2) is provided with a protection circuit, which includes a Zener diode (51) and a fourth resistor (52). The Zener diode (51) and the fourth resistor (52) are connected in parallel between the gate of the field-effect transistor (31) and the negative terminal of the power supply (1).

4. The soft-start device for railway locomotive headlights according to claim 1, characterized in that: The PCB board (2) is provided with a diode (6), and the two ends of the diode (6) are electrically connected to the drain of the field-effect transistor (31) and the source of the field-effect transistor (31), respectively.

5. A soft-start device for railway locomotive headlights according to claim 4, characterized in that: A current-limiting resistor (61) is provided at each end of the diode (6).

6. A soft-start device for railway locomotive headlights according to any one of claims 1-5, characterized in that: The PCB board (2) is mounted on the mounting base (7), and the PCB board (2) is provided with wiring terminals (71).

7. A soft-start device for railway locomotive headlights according to claim 6, characterized in that: The PCB board (2) has through mounting holes around its perimeter. Bolts (72) are installed in the mounting holes. The bolts (72) slide through the mounting holes and are threadedly connected to the mounting base (7).

8. A soft-start device for railway locomotive headlights according to claim 7, characterized in that: The bolt (72) is fitted with a nylon pad (73), and the two sides of the nylon pad (73) abut against the PCB board (2) and the mounting base (7) respectively.

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