US3917969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric load control
Assignee: Individual
•
Filing: 1973-11-16
•
Granted: 1975-11-04
•
Expires: 1993-11-16
Abstract
Abstract A secondary electric load is connected to a source of electric potential through a thyristor the activation of which is controlled automatically by a current transformer which senses the electric current in the main supply circuit or in the supply circuit of a primary load, the thyristor being deactivated when the sensed current reaches a predetermined magnitude.
Inventors
- 👤 John G Olsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:00
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/30; H03K17/305
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
149 words
A control for an electric load circuit connected to an electric supply circuit, comprising: a. thyristor means in said load circuit arranged in series with the load, b. the thyristor means including a gate control element having an electric gate voltage supply circuit, c. switch means in said gate voltage supply circuit for selectively supplying and removing gate voltage for said thyristor means, d. electric switch operator means having an electric circuit, and e. a current transformer in the electric switch operator means and arranged to operatively couple the circuit of the switch operator means to said electric supply circuit in parallel with the circuit of the load for sensing the electric current in said supply circuit, f. the electric switch operator means being activated upon attainment of a predetermined magnitude of sensed current in the supply circuit to operate the switch means to open the electric load circuit.
Claim 2
Dependent Claim
149 words
A control for an electric load circuit connected to an electric supply circuit, comprising: a. thyristor means in said load circuit arranged in series with the load, b. the thyristor means including a gate control element having an electric gate voltage supply circuit, c. switch means in said gate voltage supply circuit for selectively supplying and removing gate voltage for said thyristor means, d. electric switch operator means having an electric circuit, and e. a current transformer in the electric switch operator means and arranged to operatively couple the circuit of the switch operator means to said electric supply circuit in parallel with the circuit of the load for sensing the electric current in said supply circuit, f. the electric switch operator means being activated upon attainment of a predetermined magnitude of sensed current in the supply circuit to operate the switch means to open the electric load circuit.
Claim 3
Dependent Claim
14 words
The control of claim 1 wherein thE current transformer is a toroidal current transformer.
Claim 4
Dependent Claim
26 words
The control of claim 1 wherein the switch means is the contact of a relay and the switch operator means is the coil of said relay.
Claim 5
Dependent Claim
28 words
The control of claim 3 including variable resistance means across said coil for effecting activation of the relay at various selected load levels sensed by the current transformer.
Claim 6
Dependent Claim
20 words
The control of claim 1 wherein the current transformer is arranged to be coupled directly to said electric supply circuit.
Claim 7
Dependent Claim
43 words
The control of claim 1 wherein a second electric load circuit is connected to the electric supply circuit in parallel with the load circuit to be controlled, and wherein the current transformer is arranged to be coupled to said second electric load circuit.
References Cited (Backward Citations)
US3260898A
Cited
US3392626A
Cited
US3486042A
Cited
US3588598A
Cited
US3603817A
Cited
US3668422A
Cited
US3699390A
Cited
US3715623A
Cited
US3723769A
Cited
US3745382A
Cited
US3758793A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |