Method and apparatus for detecting shorted rectifying control elements of an engine driven power source for welding-type system
First Claim
1. A shorted rectifying control element detection device comprising:
- an input stage connected to an engine driven generator configured to supply power for a welding-type process;
a filtering stage to bandpass current signals acquired by the input stage from the engine driven generator; and
an output stage connected to the filtering stage and configured to at least indicate a fault condition if fundamental frequency components present in the current signals exceed a threshold.
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Accused Products
Abstract
An apparatus for electrical protection of an electrical system includes a protection circuit for detecting when silicon controlled rectifier (SCR) or other control elements in an engine driven generator of a welding-type power source have failed. In such an apparatus, a shorted rectifying control element detection device has an input stage connected to an engine driven generator that supplies power for a welding-type process and a filtering stage to bandpass current signals acquired by the input stage from the engine driven generator. The apparatus further has an output stage connected to the filtering stage that at least indicates a fault condition if fundamental frequency components present in the current signals exceed a threshold.
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Citations
19 Claims
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1. A shorted rectifying control element detection device comprising:
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an input stage connected to an engine driven generator configured to supply power for a welding-type process;
a filtering stage to bandpass current signals acquired by the input stage from the engine driven generator; and
an output stage connected to the filtering stage and configured to at least indicate a fault condition if fundamental frequency components present in the current signals exceed a threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An engine driven welding-type system comprising:
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a synchronous wound field generator having a rotor magnetically coupled to a stator;
an SCR bridge connected to be supplied with power from the generator and configured to rectify the power into a form usable in a welding-type process;
a fault detection circuit designed to determine if stator induced fundamental frequency components are present in current flowing through the rotor; and
a fault indicator connected to the fault detection circuit and configured to output a fault present signal. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A short circuit detection device for an engine driven generator, the detection device comprising:
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means for detecting current in a rotor of a generator;
means for low pass filtering and means for high pass filtering the current, the means for low pass filtering includes means for rejecting 120 Hz component that occurs under a single phase load and the means for high pass filtering includes means for rejecting normal operation DC components present in the current;
means for isolating frequency components in the current indicative of a stator induced DC component; and
means for determining a short from the isolated frequency components. - View Dependent Claims (17, 18)
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19. A method of detecting a shorted SCR of an engine driven welding-type power source comprising the steps of:
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detecting current in a rotor of an engine driven generator configured to supply power for a welding-type process;
isolating frequency components in the current indicative of a stator induced DC component; and
determining if a shorted SCR condition is present from the isolated frequency components.
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Specification