US3764870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control systems for battery operated vehicles
Assignee: Cableform Ltd
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Filing: 1972-01-20
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Granted: 1973-10-09
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Expires: 1992-01-20
Abstract
Abstract In some control systems for controlling the supply of electrical energy from a battery to the electric motor of a vehicle it is desirable in certain circumstances to use the maximum available current which may be in excess of that available through a thyristor type D.C. switch. Rather than increase the rating of the D.C. switch to cope with these occasional demands there are provided a by-pass contactor having contacts which, when closed, shunt the D.C. switch, means operable by a speed controller in its maximum speed demand condition included in an enabling circuit of the by-pass contactor and time delay means for delaying the energisation of the by-pass contactor as a function of the motor current.
Inventors
- 👤 J Morton
- 👤 K Stevens
- 👤 G Thexton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:11
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/18
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
81 words
A control system for the electric motor of a battery operated vehicle, comprising a D.C. switch for controlling the supply of current from a battery to the electric motor, a by-pass contactor having contacts which, when closed, shunt the D.C. switch, means operable by a speed controller in its maximum speed demand condition included in an enabling circuit of the by-pass contactor and time delay means for delaying the energisation of the by-pass contactor as a function of the motor current.
Claim 2
Dependent Claim
81 words
A control system for the electric motor of a battery operated vehicle, comprising a D.C. switch for controlling the supply of current from a battery to the electric motor, a by-pass contactor having contacts which, when closed, shunt the D.C. switch, means operable by a speed controller in its maximum speed demand condition included in an enabling circuit of the by-pass contactor and time delay means for delaying the energisation of the by-pass contactor as a function of the motor current.
Claim 3
Dependent Claim
42 words
A system as claimed in claim 1, wherein a signal proportional to the motor current controls the delay time of the time delay means, a clamp means being provided to prevent the time delay means from operating until predetermined conditions are met.
Claim 4
Dependent Claim
45 words
A sYstem as claimed in claim 1, wherein a signal proportional to the motor current controls the rate of charge of a capacitor which remains clamped by clamping means until predetermined control contacts are closed and the speed controller is in its maximum demand condition.
Claim 5
Dependent Claim
51 words
A system as claimed in claim 3, wherein the signal proportional to the motor current is obtained by including a resistor in the current path of the motor, the voltage developed across the resistor being used to control the current through a transistor included in the charging path of the capacitor.
Claim 6
Dependent Claim
27 words
A system as claimed in claim 3, wherein the clamping means comprises a transistor connected across the capacitor and being conductive until said predetermined conditions are met.
Claim 7
Dependent Claim
53 words
A system as claimed in claim 3, wherein the voltage developed across the capacitor due to charging is fed to a bi-stable switching circuit which changes state when the capacitor voltage reaches a predetermined level and thereby causes energisation of a relay having contacts included in the energisation circuit of the by-pass contactor.
Claim 8
Dependent Claim
54 words
A system as claimed in claim 4, wherein the voltage developed across the resistor in the path of the motor current is compared with a reference voltage representing a threshold current the resultant signal, when the voltage representing the motor current exceeds the reference voltage, being used to control the charging of the capacitor.
Claim 9
Dependent Claim
38 words
A system as claimed in claim 1, wherein means is provided to switch-off the D.C. switch immediately prior to operation of the by-pass contactor and to ensure that it remains off until the by-pass contactor can be opened.
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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |