CN2128743Y - Electric source protecting alarm for light welding machine - Google Patents

Abstract

The utility model relates to a power source monitoring instrument which is suitable in particular for power source of light welder whose voltage is easy to descend during the working process. A printed circuit board is provided with an adjustable resistor R-[2] whose one fixed end is connected with the positive pole of the power source and one roller end is connected with the non-inverting input end of a comparator LM741, and a zener diode DW whose one end is earthed and the other end is connected with the negative input end of the comparator LM741. The output end of the comparator LM741 is connected with the base of a transistor BG1 whose collector is connected with the base of a transistor BG2. A resistance R5 is connected with a collector circuit of BG1. The emitter of BG2 is connected with the supply line of a multivibrator on the printed circuit board and an alarm is connected to the multivibrator circuit. Thereby, the utility model ensures welding quality and also extends the service life of the battery supply.

Description

Electric source protecting alarm for light welding machine

The utility model relates to a kind of power supply monitoring instrument, especially is applicable in the easy welding machine power supply that descends of Power Operating Process voltage.

At present, the connection that connects line between open-air railway line rail has generally adopted welding machine and corresponding welding gun with battery feed to carry out soldering, both has been convenient to field construction, can guarantee quality of connection (connecting firm and the rail not damaged) again.But accumulator is along with the passing of service time, and voltage can descend, and the power supply that continues working voltage decline not only reduces welding quality greatly as the source of welding current, but also the serviceable life of meeting major injury accumulator.

The purpose of this utility model is that a kind of welding machine power protection warning horn will be provided, and can indicate the normal and up-set condition of battery tension in welding process, to guarantee welding quality and the serviceable life of improving accumulator.

The purpose of this utility model is achieved in that being provided with a stiff end on printed circuit board (PCB) connects positive source, one movable terminal connects the adjustable resistance R2 of comparer LM741 normal phase input end, be provided with an end ground connection, the other end connects the voltage stabilizing diode DW of comparer LM741 negative-phase input, the output terminal of comparer LM741 connects transistor BG1 base stage, the BG1 collector connects transistor BG2 base stage, on the collector circuit of transistor BG1, connect resistance R 5, the emitter of BG2 is connected in the multivibrator supply line on the printed circuit board (PCB), connects a warning horn in multivibrator circuit.When supply voltage is higher than 37.5 volts, adjust the R2 resistance value, make current potential be elevated to predetermined value, make LM741 amplify the output noble potential, make the BG1 conducting, the supply voltage major part is fallen on R5, the BG2 base potential is descended, and BG2 is in cut-off state, and promptly the emitter current potential is zero, multivibrator is not worked, and warning horn is not worked yet and represented that supply voltage is normal.When supply voltage drops to 37.5 volts, the voltage signal got on R2 input LM741, its output terminal current potential descends, and the conducting of BG1 changes into and ends, its collector circuit no current, thereby collector potential raises, drive BG2 base potential raises, and BG2 changes saturation conduction into, and emitter is near collector potential, multivibrator circuit is connected, warning horn (flashlamp flash of light) work, the expression supply voltage is undesired, needs charging process.

Owing to adopt such scheme, the power supply that can control welding machine just often provides the power supply of welding at voltage, has guaranteed welding quality, has also improved the serviceable life of battery feed.

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is the diagrammatic cross-section of an embodiment of the utility model.

Fig. 2 is the circuit theory diagrams of an embodiment of the utility model.

Among the figure: 1. case shell, 2. dividing plate, 3. panel, 4. printed circuit board (PCB), D. multivibrator, S. battery feed, R1, R3～R5. resistance, R2. adjustable resistance (sample resistance), DW. stabilivolt, LM741. comparer, BG1, BG2. transistor, ZD1. warning horn (flashlamp).

At embodiment illustrated in figures 1 and 2 is with the BB6688 flush weld power protection warning horn of three joint accumulator series connection as power supply.

In Fig. 1; the wall middle part connects a block length square spacer plate 2 with screw around the rectangle case shell 1; dividing plate 2 back connect the battery feed S of three joint series connection; dividing plate 2 fronts connect printed circuit board (PCB) 4 with screw; on printed circuit board (PCB) 4, be provided with multivibrator D and this power protection indicator circuit integrated package; rectangular faceplate 3 is inlayed and is connected case shell 1 front end with screw, and welding machine power supply positive and negative electrode socket and warning horn (flashlamp) ZD1 etc. are housed on panel 3.

In Fig. 2, the normal voltage that the power supply of three joint accumulator series connection is supplied with is 38.5 volts, and when supply voltage was reduced to 37.5 volts, power supply should not continue to use, and in this power protection alarm circuit, with flashlamp display power supply up-set condition.

Adjustable resistance R2(takes by weighing sample resistance again) a stiff end connect 38.5 volts of positive sources, one movable terminal connects the normal phase input end A point of comparer LM741, be used for extracting voltage signal from tested power circuit, and send into the A point of comparer LM741, signal amplifies the output terminal B point output of back from comparer LM741, is used for the base potential of oxide-semiconductor control transistors BG1.Resistance R 1, R3 connect with adjustable resistance R2, and resistance R 4 is as the inclined to one side value resistance of transistor BG1.

Stabilivolt DW one end ground connection, the other end connect comparer LM741 negative-phase input, for reference potential of LM741.

When supply voltage is higher than 37.5 volts, adjust the resistance value of adjustable resistance R2, make A point current potential be elevated to predetermined value, amplify through comparer LM741, B point current potential raises, promote transistor BG1 conducting, at this moment, the most of pressure drop (R5 is as inclined to one side value resistance of transistor BG2) on the resistance R between collector and positive source 5 of power supply, transistor BG1 emitter, the current potential of inter-collector is near zero potential (grounded emitter), the base stage of transistor BG2 is connected with transistor BG1 collector, thereby the BG2 base potential descends, and BG2 is in cut-off state, multivibrator D is in off position, warning horn in its circuit (flashlamp) ZD1 does not glisten, and the expression supply voltage is normal, can continue welding.

When supply voltage drops to 37.5 volts, from adjustable resistance R2(sample resistance) voltage signal got input LM741, amplify through LM741, output terminal B point current potential is descended, BG1 changes into from saturation conduction and ends, its collector circuit no current, thereby collector potential raises and near 37.5 volts, the base potential that drives BG2 simultaneously raises, and makes BG2 change saturation conduction into from ending, and the circuit of multivibrator D is connected (in running order), warning horn (flashlamp) ZD1 flash of light, the expression supply voltage is undesired, should stop welding, need charge a battery, make voltage return to 38.5 volts, just can continue as welding then power supply is provided.

Claims (2)

1; a kind of welding machine power protection warning horn; comprise the case shell; dividing plate; printed circuit board (PCB); panel and multivibrator; it is characterized in that: on printed circuit board (PCB), be provided with a stiff end and connect positive source; one movable terminal connects the adjustable resistance R2 of comparer LM741 normal phase input end; be provided with an end ground connection; the other end connects the voltage stabilizing diode DW of comparer LM741 negative-phase input; the output terminal of comparer LM741 connects transistor BG1 base stage; the BG1 collector connects transistor BG2 base stage; on the collector circuit of transistor BG1, connect resistance R 5; the emitter of BG2 is connected in the multivibrator supply line on the printed circuit board (PCB), connects a warning horn in multivibrator circuit.

2, by the described welding machine power protection of claim 1 warning horn, it is characterized in that: warning horn is a flashlamp.

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