US3895264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ground connection monitoring apparatus for mobile machines
Assignee: Mosebach Manufacturing Co
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Filing: 1974-01-08
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Granted: 1975-07-15
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Expires: 1994-01-08
Abstract
Abstract Apparatus protected against ground faults for monitoring the ground connection between a grounded power source and a mobile machine provided with multi-phase power through a multi-conductor trailing cable has a star arrangement of impedances connected to the phase conductors at the power source and a like arrangement connected at the machine, the junctions of which are connected to the ground conductor at each end, through a silicon-controlled rectifier device which is paralleled by a monitoring impedance. At least one impedance of one of the star arrangement of impedances is adjusted to provide a low monitoring voltage which circulates a current through the ground conductor and monitoring impedance. The voltage across the latter actuates monitoring means. The silicon-controlled rectifier is adjusted to conduct when the voltage across it rises above the monitoring level. The monitoring current may be alternating current, or direct current obtained from a rectifier in circuit with the ground conductor.
Inventors
- 👤 Victor V Kirilloff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:10
CPC Classifications
H; H02; H02H; H02H11/00; H02H11/001; H02H3/00; H02H3/26; H02H3/32; H02H3/34; H02H3/353
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
130 words
Apparatus for monitoring the ground connection between a mobile electrically driven machine supplied with multi-phase current through a multi-conductor trailing cable including a ground conductor attached at one end to the frame of the machine from a grounded power source, comprising a triggered solid-state breakdown device connecting the other end of the ground conductor with ground, a monitoring impedance in parallel with the triggered solid-state breakdown device, means deriving from the phase conductors a monitoring current flowing through the monitoring impedance and ground conductor, phase conductor interrupting means at the power source, and monitoring means connected across the monitoring impedance adapted to operate the phase conductor interrupting means when the current through the monitoring impedance increases above a value corresponding to the firing voltage of the triggered solid-state breakdown device.
Claim 2
Dependent Claim
130 words
Apparatus for monitoring the ground connection between a mobile electrically driven machine supplied with multi-phase current through a multi-conductor trailing cable including a ground conductor attached at one end to the frame of the machine from a grounded power source, comprising a triggered solid-state breakdown device connecting the other end of the ground conductor with ground, a monitoring impedance in parallel with the triggered solid-state breakdown device, means deriving from the phase conductors a monitoring current flowing through the monitoring impedance and ground conductor, phase conductor interrupting means at the power source, and monitoring means connected across the monitoring impedance adapted to operate the phase conductor interrupting means when the current through the monitoring impedance increases above a value corresponding to the firing voltage of the triggered solid-state breakdown device.
Claim 3
Dependent Claim
27 words
Apparatus of claim 1 in which the monitoring means are adapted to operate the phase conductor interrupting means when the monitoring current falls below a predetermined value.
Claim 4
Dependent Claim
33 words
Apparatus of claim 1 in which the means for deriving a monitoring current from the phase conductors comprise an unbalanced star arrangement of capacitors connected to the phase conductors at the power source.
Claim 5
Dependent Claim
24 words
Apparatus of claim 1 in which the means deriving the monitoring current are located at the power source and provide a direct monitoring current.
Claim 6
Dependent Claim
50 words
Apparatus of claim 1 in which the monitoring means include a differential amplifier, one input of which is connected to a direct voltage proportional to the voltage across the monitoring impedance, the other input to a reference direct voltage, and the output is connected to the phase conductor interrupting means.
Claim 7
Dependent Claim
227 words
Apparatus for monitoring the ground connection between a mobile electrically driven machine supplied with multi-phase current through a multi-conductor trailing cable including a ground conductor attached at one end to the frame of the machine from a grounded power source, comprising a solid-state breakdown device connecting the other end of the ground conductor with ground, a monitoring impedance in parallel with the solid-state breakdown device, monitoring means connected across the monitoring impedance, a star arrangement of impedances connected to the phase conductors at the machine, a star arrangement of impedances connected to the phase conductors at the power source, means connecting the junctions of the star arrangement of impedances at the machine with the machine frame, means connecting the junction of the star arrangement of impedances at the power source with ground, at least one impedance of one of the star arrangements of impedances being adjusted to provide a low monitoring voltage in circuit with the ground conductor, phase conductor interrupting means at the power source, means for converting the voltage across the monitoring impedance to direct voltage, and actuating means for those interrupting means triggered by a change in current through the monitoring impedance, those actuating means comprising a differential amplifier, one input of which is connected to the said direct voltage, the other to a reference direct voltage, and the output with the interrupting means.
Claim 8
Dependent Claim
227 words
Apparatus for monitoring the ground connection between a mobile electrically driven machine supplied with multi-phase current through a multi-conductor trailing cable including a ground conductor attached at one end to the frame of the machine from a grounded power source, comprising a solid-state breakdown device connecting the other end of the ground conductor with ground, a monitoring impedance in parallel with the solid-state breakdown device, monitoring means connected across the monitoring impedance, a star arrangement of impedances connected to the phase conductors at the machine, a star arrangement of impedances connected to the phase conductors at the power source, means connecting the junctions of the star arrangement of impedances at the machine with the machine frame, means connecting the junction of the star arrangement of impedances at the power source with ground, at least one impedance of one of the star arrangements of impedances being adjusted to provide a low monitoring voltage in circuit with the ground conductor, phase conductor interrupting means at the power source, means for converting the voltage across the monitoring impedance to direct voltage, and actuating means for those interrupting means triggered by a change in current through the monitoring impedance, those actuating means comprising a differential amplifier, one input of which is connected to the said direct voltage, the other to a reference direct voltage, and the output with the interrupting means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |