US3840801A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Indicator light testing circuit
Assignee: Westinghouse Electric Corp
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Filing: 1973-09-18
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Granted: 1974-10-08
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Expires: 1993-09-18
Abstract
Abstract A circuit for testing indicator lights whereby multiple lights may be tested simultaneously by pressing one pushbutton and closing one set of normally open contacts. The test pushbutton and the indicator signal operate at a higher voltage such as 120 volts AC and the indicator lamp is operated at a low voltage such as 6 volts, providing safety and allowing use of inexpensive incandescent indicator bulbs. Only one indicator transformer is required for each indicator light. In one embodiment of the invention a pair of diodes are provided on the high voltage side of the indicator transformer to permit a test signal or a normal operating signal to activate the indicator bulb without affecting the rest of the circuit. A single common line is used to provide a return line for the test circuit and the operating signal circuit. In another embodiment of the invention a single diode is provided on the high voltage side of each indicator transformer for feeding a rectified AC signal to the indicator bulb and for isolating the indicator circuits. An AC normal operating signal can also be fed through the indicator circuit. This embodiment requires the use of only a single diode with each indicator transformer while providing for a single pushbutton test. A common return line is used for the test circuit and normal operating circuit. The illumination of the indicator bulbs when activated through the test circuit can be less than the illumination when activated through the normal indicator signal circuit.
Inventors
- 👤 W Kellogg
- 👤 G Taylor
- 👤 C Calvin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:47
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/44; G08; G08B; G08B29/00; G08B29/12; G08B29/126
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
140 words
An indicator light circuit comprising: a plurality of indicator lights; a transformer associated with each of said indicator lights having a primary side and a secondary side with only said assocIated indicator light being connected across the secondary of said transformer; test circuit means connected to the primary of each of said transformers for supplying a test current to the primary of all of said transformers when a check of said plurality of indicator lights is required; signal circuit means associated with each of said plurality of transformers for supplying current to the primary of said associated transformer in response to operation of an external component; and isolating means disposed in the primary connection to each of said transformers for preventing current flow from said signal circuit means through said test circuit means to the primary of any other transformer.
Claim 2
Dependent Claim
140 words
An indicator light circuit comprising: a plurality of indicator lights; a transformer associated with each of said indicator lights having a primary side and a secondary side with only said assocIated indicator light being connected across the secondary of said transformer; test circuit means connected to the primary of each of said transformers for supplying a test current to the primary of all of said transformers when a check of said plurality of indicator lights is required; signal circuit means associated with each of said plurality of transformers for supplying current to the primary of said associated transformer in response to operation of an external component; and isolating means disposed in the primary connection to each of said transformers for preventing current flow from said signal circuit means through said test circuit means to the primary of any other transformer.
Claim 3
Dependent Claim
41 words
An indicator light circuit as claimed in claim 1 wherein: a first diode is disposed in the test circuit means connection to each of said transformers; and, said signal circuit means and said test circuit means share a common return line.
Claim 4
Dependent Claim
46 words
An indicator light circuit as claimed in claim 2 including: a second diode connected in the signal circuit connection to each of said plurality of transformers and being disposed to pass current of the same polarity as the current which can pass through said first diode.
Claim 5
Dependent Claim
110 words
An indicator light circuit comprising: a plurality of transformers having a primary side and a secondary side; a plurality of indicator lights each being connected across the secondary of one of said plurality of transformers; a plurality of signal circuits each being connected to the primary of one of said plurality of transformers; a test circuit for testing the operability of said plurality of indicator lights connected to the primary of all of said plurality of transformers; and isolating means disposed in the primary connection to each of said transformers for preventing current flow from one of said plurality of signal circuits to another of said plurality of signal circuits.
Claim 6
Dependent Claim
110 words
An indicator light circuit comprising: a plurality of transformers having a primary side and a secondary side; a plurality of indicator lights each being connected across the secondary of one of said plurality of transformers; a plurality of signal circuits each being connected to the primary of one of said plurality of transformers; a test circuit for testing the operability of said plurality of indicator lights connected to the primary of all of said plurality of transformers; and isolating means disposed in the primary connection to each of said transformers for preventing current flow from one of said plurality of signal circuits to another of said plurality of signal circuits.
Claim 7
Dependent Claim
41 words
An indicator light circuit as claimed in claim 4, wherein said isolating means comprises: a first plurality of uni-directional current conductors each being disposed in the connection of said test circuit to the primary of each of said plurality of transformers.
Claim 8
Dependent Claim
82 words
An indicator light circuit as claimed in claim 5, wherein said isolating means comprises: a second plurality of uni-directional current conductors each being disposed in the connection of one of said plurality of signal circuits to one of said transformers; and, each uni-directional current conductor oriented so as to pass current of a polarity which will be blocked by one of said first plurality of uni-directional current conductors disposed in the connection of said test circuit to the primary of said transformer.
Claim 9
Dependent Claim
30 words
An indicator light circuit as claimed in claim 6 including: a common return line forming a part of said plurality of signal circuits and a part of said test circuit.
Claim 10
Dependent Claim
177 words
An indicator light circuit comprising: a plurality of indicator lights; an indicator transformer for each of said plurality of indicator lights having a high voltage side and a low voltage side; each of said indicator lights being connected to the low voltage side of said associated indicator transformer; each of said indicator transformers having a first high voltage side leg and a second high voltage side leg; an alternating current test current source; a normally open pushbutton having an input connection, connected to said alternating current test current source, and an output connection; a test line for each indicator transformer disposed between and connected to the first high voltage side leg of said indicator transformer and the output connection of said normally open pushbutton; a diode disposed in each of said test lines limiting current flow to one direction; an operating signal line connected to the first high voltage side leg of each of said indicator transformers; and, signal indicator means for energiZing each of said signal lines with an alternating current in response to external signals.
Claim 11
Dependent Claim
177 words
An indicator light circuit comprising: a plurality of indicator lights; an indicator transformer for each of said plurality of indicator lights having a high voltage side and a low voltage side; each of said indicator lights being connected to the low voltage side of said associated indicator transformer; each of said indicator transformers having a first high voltage side leg and a second high voltage side leg; an alternating current test current source; a normally open pushbutton having an input connection, connected to said alternating current test current source, and an output connection; a test line for each indicator transformer disposed between and connected to the first high voltage side leg of said indicator transformer and the output connection of said normally open pushbutton; a diode disposed in each of said test lines limiting current flow to one direction; an operating signal line connected to the first high voltage side leg of each of said indicator transformers; and, signal indicator means for energiZing each of said signal lines with an alternating current in response to external signals.
Claim 12
Dependent Claim
32 words
An indicator light circuit as claimed in claim 8 comprising: a common conductor; conducting means connecting the second high voltage side leg of each of said indicator transformers to said common conductor.
Claim 13
Dependent Claim
56 words
An indicator light circuit as claimed in claim 9 comprising: a signal circuit diode disposed in each of said signal conductors; each of said signal circuit diodes being oriented so to permit current flow through the high voltage side of said indicator transformer in the same direction as that permitted by the associated test circuit diode.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |