Patent DE683480C successfully refreshed from Google Patents.
Patent US6576943B1 successfully refreshed from Google Patents.
Patent US7265522B2 successfully refreshed from Google Patents.
US4091431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ground leakage relay circuit
Assignee: Hubbell Inc
•
Filing: 1970-10-09
•
Granted: 1978-05-23
•
Expires: 1990-10-09
Abstract
Abstract A ground leakage relay circuit including a core balance transformer through which pass the supply and return line of the circuit to be protected and having a multi-turn secondary winding. A capacitor is connected to be normally charged from a d.c. source. A normally conducting transistor is connected across the capacitor. When the transformer secondary winding exceeds a preselected level, the transistor is switched "off" to permit a voltage build-up across the capacitor. When the voltage across the capacitor reaches a triggering value, it actuates a relay to open the supply line.
Inventors
- 👤 Alton R. Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:56
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/33
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
161 words
A ground leakage relay circuit for use in an alternating current system including at least one supply line and a return which comprises: detection means responsive to the vector sum of the currents in said supply line and return to produce an error signal proportional thereto; capacitance means; diode means in series with said capacitance means; d.c. supply means connected to charge said capacitance means; shunt means in parallel with said capacitance means and diode means and having a high impedance state and a low impedance state; control circuit means responsive to said error signal to change said shunt means from its low impedance state to its high impedance state during the existence of an error signal of preselected amplitude; circuit breaker means in at least said supply line; and circuit breaker actuating means responsive to the charge on said capacitance means to open said circuit breaker means on the occurrence of a voltage of preselected amplitude across said capacitance means.
Claim 2
Dependent Claim
161 words
A ground leakage relay circuit for use in an alternating current system including at least one supply line and a return which comprises: detection means responsive to the vector sum of the currents in said supply line and return to produce an error signal proportional thereto; capacitance means; diode means in series with said capacitance means; d.c. supply means connected to charge said capacitance means; shunt means in parallel with said capacitance means and diode means and having a high impedance state and a low impedance state; control circuit means responsive to said error signal to change said shunt means from its low impedance state to its high impedance state during the existence of an error signal of preselected amplitude; circuit breaker means in at least said supply line; and circuit breaker actuating means responsive to the charge on said capacitance means to open said circuit breaker means on the occurrence of a voltage of preselected amplitude across said capacitance means.
Claim 3
Dependent Claim
13 words
The circuit of claim 1 wherein said detection means comprises a differential transformer.
Claim 4
Dependent Claim
15 words
The circuit of claim 1 wherein said shunt means comprises first solid state switching means.
Claim 5
Dependent Claim
15 words
The circuit of claim 3 wherein said first solid state switching means is a transistor.
Claim 6
Dependent Claim
42 words
The circuit of claim 3 wherein said first solid state switching means forms the second stage of a Schmitt trigger circuit and wherein said control circuit means comprises second solid state switching means forming the first stage of said Schmitt trigger circuit.
Claim 7
Dependent Claim
36 words
The circuit of claim 5 wherein said control circuit means additionally comprises third solid state switching means having its output connected to said second solid state switching means and its input connected to said detection means.
Claim 8
Dependent Claim
16 words
The circuit of claim 1 wherein a discharge impedance means is connected across said capacitance means.
Claim 9
Dependent Claim
21 words
The circuit of claim 7 wherein the charging time constant of said capacitance means is less than its discharge time constant.
Claim 10
Dependent Claim
61 words
The circuit of claim 1 wherein said circuit breaker actuating means comprises: a relay coil; solid state switching means in series with said relay coil and having a normally high impedance state but actuatable to a low impedance state; and means responsive to the charge on said capacitance means to actuate said solid state switching means to its low impedance state.
Claim 11
Dependent Claim
15 words
The circuit of claim 9 wherein said solid state switching means is a controlled rectifier.
References Cited (Backward Citations)
US3286129A
Cited
US3213321A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |