EP0034477A1
Expired / Lapsed
EP
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A power source circuit for an electric discharge machine
Assignee: Fanuc Corp
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Filing: 1981-02-13
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Granted: —
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Expires: 2001-02-13
Abstract
Abstract There is provided a power source circuit for use with an electric discharge machine which machines a work (W) by a discharge produced between an electrode (P) and the work (W). When an arc forms in a working gap defined between the electrode P and the work (W), the OFF period of a switching element (Q) inserted in a charging path of a capacitor (C) for storing a discharge energy is increased so that a current flowing across the working gap is cut off for a longer period of time than in the case of a normal operation, thereby quickly recovering insulation during arcing.
Inventors
- 👤 Syunzo Izumiya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 00:33
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/024
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
188 words
A power source circuit for an electric discharge machine, in which circuit a capacitor is to be charged by a power supply via a switching element, and the charged voltage of the capacitor is to be applied across a working gap between an electrode and a work when the circuit is in operation, characterised in that the power source circuit comprises: a first oscillator for producing a pulsed signal having predetermined ON and OFF periods; a second oscillator which is arranged such that every time the working gap voltage drops below a predetermined value when the power source circuit is in use, the second oscillator is started to produce first an ON pulse of a longer duration than that of the pulsed signal of the first oscillator and next an OFF pulse of a longer duration than the OFF period of the pulsed signal of the first oscillator and thereafter repeats alternate generation; and logic circuitry arranged such that a logic function signal of output signals from the first and second oscillators is comprised in a drive signal to the switching element when the circuit is in use.
Claim 2
Dependent Claim
188 words
A power source circuit for an electric discharge machine, in which circuit a capacitor is to be charged by a power supply via a switching element, and the charged voltage of the capacitor is to be applied across a working gap between an electrode and a work when the circuit is in operation, characterised in that the power source circuit comprises: a first oscillator for producing a pulsed signal having predetermined ON and OFF periods; a second oscillator which is arranged such that every time the working gap voltage drops below a predetermined value when the power source circuit is in use, the second oscillator is started to produce first an ON pulse of a longer duration than that of the pulsed signal of the first oscillator and next an OFF pulse of a longer duration than the OFF period of the pulsed signal of the first oscillator and thereafter repeats alternate generation; and logic circuitry arranged such that a logic function signal of output signals from the first and second oscillators is comprised in a drive signal to the switching element when the circuit is in use.
Claim 3
Dependent Claim
34 words
A power source circuit according to claim 1, wherein the second oscillator is arranged to be started by the output signal from a comparator which compares the working gap voltage with said predetermined value.
Claim 4
Dependent Claim
18 words
A power source circuit according to claim 1 or 2, wherein said logic function is an AND function.
Claim 5
Dependent Claim
57 words
A power source circuit according to any one of the preceding claims, wherein when the circuit is in use said drive signal comprises a further logic function signal of.the first-mentioned logic function.. signal and aπ output signal from a further comparator which issues a signal when said working gap voltage is higher than a further predetermined value.
Claim 6
Dependent Claim
17 words
A power source circuit according to claim 4, wherein said further logic function is an OR function.
Claim 7
Dependent Claim
21 words
A power source circuit according to claim 4 or 5, wherein the two predetermined values are substantially equal to one another.
Claim 8
Dependent Claim
50 words
A power source circuit according to any one of the preceding claims, wherein the first-mentioned predetermined value is of such a value that the working gap voltage will stay below the value in the event of an arc being caused in the working gap when the circuit is in use.
Claim 9
Dependent Claim
54 words
A power source circuit according to claim 4, 5 or 6, or claim 7 when appended thereto, wherein the further predetermined value is of such a value that the working gap voltage will stay below the value in the event of an arc being caused in the working gap when the circuit is in.use.
References Cited (Backward Citations)
JPH10133780A
Cited
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