Patent US3611036A successfully refreshed from Google Patents.
US3611036A
Expired / Lapsed
US
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Ground fault detector for electric motors
Assignee: Occidental Petroleum Corp
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Filing: 1970-01-21
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Granted: 1971-10-05
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Expires: 1990-01-21
Abstract
Abstract There is described a ground-detecting circuit for a motor or other electrical load wherein, before the motor is turned on, two terminals of the motor are connected to two input power lines through diodes in series with neon lamps and current-limiting resistors. A ground in the motor produces a current flow through one or both lamps. A photosensitive resistor, in response to the light from the lamps, activates a relay control circuit to open the input line to the motor, so that the motor cannot be turned on.
Inventors
- 👤 Robert W Edson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:03
CPC Classifications
H; H02; H02H; H02H11/00; H02H11/005
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
110 words
A ground fault detector circuit for indicating a grounded condition of an electrical load device adapted to be operated from an alternating current source, said circuit comprising switch means for connecting the sourCe to the load, first and second series circuits connecting two terminals of the source respectively to two terminals of the load and shunting the switch means, each series circuit including a rectifier and a current indicating element, the two rectifiers being connected to provide minimum resistance to current flow in opposite directions relative to each other to normally block current flow in either direction through the load device from the source when the switch means is open.
Claim 2
Dependent Claim
110 words
A ground fault detector circuit for indicating a grounded condition of an electrical load device adapted to be operated from an alternating current source, said circuit comprising switch means for connecting the sourCe to the load, first and second series circuits connecting two terminals of the source respectively to two terminals of the load and shunting the switch means, each series circuit including a rectifier and a current indicating element, the two rectifiers being connected to provide minimum resistance to current flow in opposite directions relative to each other to normally block current flow in either direction through the load device from the source when the switch means is open.
Claim 3
Dependent Claim
18 words
Apparatus as defined in claim 1 wherein the indicating element in each series circuit comprises a light-emitting unit.
Claim 4
Dependent Claim
62 words
Apparatus as defined in claim 1 further including switch means for connecting the two terminals of the load device directly to the two terminals of the source for operating the load, and means responsive to said current indicating elements when a current is passing through either element for preventing the switch means from completing a connection between the load and the source.
Claim 5
Dependent Claim
37 words
Apparatus as defined in claim 2 further including means responsive to said current-indicating elements when a current is passing through either element for preventing the switch means from completing a connection between the load and the source.
Claim 6
Dependent Claim
45 words
Apparatus as defined in claim 4 wherein the means responsive to the current-indicating elements includes a photosensitive element, and relay means operated by said element for completing a circuit between the load device and the source only when the light-emitting units are not emitting light.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |