US3649896A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuits for an electric tractor
Assignee: General Electric Co
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Filing: 1970-02-12
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Granted: 1972-03-14
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Expires: 1990-02-12
Abstract
Abstract The main current conduction path of a controlled rectifier and a starting network therefore are connected in parallel across a source of unidirectional potential through a single pole, double throw switch. With the switch in the start position with the pole engaging one contact the starting network is connected in circuit with the source of operating potential and in the other position with the pole engaging the other contact, circuit is completed through the controlled rectifier. The triggering voltage developed by the starting network decays rapidly with time the starting network is out of circuit. Accordingly, after conduction has been established in the controlled rectifier by switching the pole of the switch from the start to the operate position, should conduction be interrupted by a safety switch in the main conduction circuit of the controlled rectifier conduction cannot be reestablished therein by simply closing the safety switch but requires the return of the single pole, double throw switch to the start position to establish triggering potential for the controlled rectifier.
Inventors
- 👤 William B Mason
- 👤 Douglas R Houst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:40
CPC Classifications
B; B60; B60K; B60K1/00; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/903; Y10S388/907; Y10S388/917
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
350 words
In an electrical network wherein a source of unidirectional voltage is coupled to a load circuit, such as a DC motor, and wherein actuation of current interrupting means, such as contactors, from a first to a second state interrupts application of unidirectional voltage from said source to said load circuit, a reset control arrangement requiring manual resetting to reapply the unidirectional voltage from said source to said load circuit, comprising: a. said source of unidirectional voltage having a positive terminal and a negative terminal; b. a unidirectional conduction control device having a cathode, an anode, and a control electrode; c. a starting network comprising an input adapted to be coupled to said source of unidirectional voltage, an output, and means for producing in said output a unidirectional control voltage decaying rapidly subsequent to removal of unidirectional voltage from the input circuit of said network; d. means coupling said output to the control electrode to cathode circuit of said control device to render said device conductive when operating voltage is applied to said anode to cathode circuit thereof and to preclude the initiation of conduction in said device subsequent to decay of said control voltage; e. switching means for alternately connecting said anode to cathode circuit and said input of said starting network in circuit between said terminals of said source, whereby when said network is switched out of circuit and said anode to cathode circuit is switched into circuit across said terminals conduction occurs in said anode to cathode circuit and the control voltage in said output circuit of said network decays to a value insufficient to initiate conduction in said control device; f. said load circuit, g. means responsive to conduction in said anode to cathode circuit to Actuate and maintain conduction in said load circuit as long as conduction exists in said anode to cathode circuit, and h. means for interrupting current flow in said anode to cathode circuit, whereby said load circuit is opened and closing the circuit between said terminals and said anode to cathode circuit path does not reestablish current flow through said control device.
Claim 2
Dependent Claim
350 words
In an electrical network wherein a source of unidirectional voltage is coupled to a load circuit, such as a DC motor, and wherein actuation of current interrupting means, such as contactors, from a first to a second state interrupts application of unidirectional voltage from said source to said load circuit, a reset control arrangement requiring manual resetting to reapply the unidirectional voltage from said source to said load circuit, comprising: a. said source of unidirectional voltage having a positive terminal and a negative terminal; b. a unidirectional conduction control device having a cathode, an anode, and a control electrode; c. a starting network comprising an input adapted to be coupled to said source of unidirectional voltage, an output, and means for producing in said output a unidirectional control voltage decaying rapidly subsequent to removal of unidirectional voltage from the input circuit of said network; d. means coupling said output to the control electrode to cathode circuit of said control device to render said device conductive when operating voltage is applied to said anode to cathode circuit thereof and to preclude the initiation of conduction in said device subsequent to decay of said control voltage; e. switching means for alternately connecting said anode to cathode circuit and said input of said starting network in circuit between said terminals of said source, whereby when said network is switched out of circuit and said anode to cathode circuit is switched into circuit across said terminals conduction occurs in said anode to cathode circuit and the control voltage in said output circuit of said network decays to a value insufficient to initiate conduction in said control device; f. said load circuit, g. means responsive to conduction in said anode to cathode circuit to Actuate and maintain conduction in said load circuit as long as conduction exists in said anode to cathode circuit, and h. means for interrupting current flow in said anode to cathode circuit, whereby said load circuit is opened and closing the circuit between said terminals and said anode to cathode circuit path does not reestablish current flow through said control device.
Claim 3
Dependent Claim
104 words
The combination of claim 1 in which said switching means is a single pole double throw switch having a pole and a pair of contacts, one of said contacts connected to one of the main current conduction electrodes of said control device, the other of said contacts connected to one of the terminals of said starting network, the other of said main current conduction electrodes of said control device and the other of said terminals of said network connected in circuit to one of said terminals of said source and said pole connected in circuit to the other of said terminals of said source.
Claim 4
Dependent Claim
14 words
The combination of claim 1 in which said load circuit includes an electric motor.
Claim 5
Dependent Claim
26 words
The combination of claim 1 in which said unidirectional conduction control device is a silicon controlled rectifier having an anode, a cathode and a control electrode.
Claim 6
Dependent Claim
15 words
The combination of claim 1 in which said starting network includes resistive and capacitive elements.
Claim 7
Dependent Claim
25 words
In an electrically driven tractor the reset control arrangement of claim 1 wherein said load circuit means comprises the drive motor circuit of said tractor.
Claim 8
Dependent Claim
28 words
The combination of claim 6 in which said current flow interrupting means includes a switch responsive to the actuation of the tractor braking mechanism to open said switch.
Claim 9
Dependent Claim
48 words
The combination of claim 6 in which said current flow interrupting means includes a switch responsive to the presence of an operator on the operator seat thereof to close said switch and responsive to the absence of an operator from the operator seat thereof to open said switch.
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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |