US3568018A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric drive and brake arrangement and method
Assignee: Motors Liquidation Co
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Filing: 1969-06-06
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Granted: 1971-03-02
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Expires: 1989-06-06
Abstract
Abstract An electric drive and dynamic braking arrangement intended in a preferred embodiment for driving and braking a vehicle, such as a heavy off-road truck, and having a pair of traction motors arranged to be driven by DC current obtained by rectifying the output of an AC generator, so as to drive the vehicle. Braking is also provided by the traction motors by separately exciting their fields with the generator output and dissipating the current generated in the traction motor armatures in resistance grids connected in series with the armatures. Rapid changeover from the power mode to the brake mode is provided by an arrangement which momentarily short-circuits the generator at the beginning of the brake mode connection to quickly reduce the residual generator voltage to a value sufficiently low to avoid overexciting the traction motors so as to prevent consequent possible damage to them.
Inventors
- 👤 Norman L Macdonald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:31
CPC Classifications
B; B60; B60L; B60L50/00; B60L50/10; B60L50/12; B60L2200/00; B60L2200/26; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/70; Y02T10/7072
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
169 words
An electric drive and braking arrangement of the type comprising: a generator; a drive motor having an armature and field windings and connectable to drive an inertia load; resistance means for absorbing power; connecting means to interconnect said components in one of three modes, namely: a power mode wherein said generator supplies current to said motor for driving said inertia load; a brake mode wherein said generator supplies current to said motor field windings and said motor armature is connected to said resistance means to dissipate power generated by said motor armature and brake said inertia load; and a short circuit mode wherein the generator is short-circuited; and control means selectively actuable to connect said connecting means in one of said power and brake modes, said control means including means to, upon selection of the brake mode, first connect said connecting means for a predetermined brief period in the short circuit mode to quickly reduce residual generator voltage and to thereafter connect the connecting means in the brake mode.
Claim 2
Dependent Claim
169 words
An electric drive and braking arrangement of the type comprising: a generator; a drive motor having an armature and field windings and connectable to drive an inertia load; resistance means for absorbing power; connecting means to interconnect said components in one of three modes, namely: a power mode wherein said generator supplies current to said motor for driving said inertia load; a brake mode wherein said generator supplies current to said motor field windings and said motor armature is connected to said resistance means to dissipate power generated by said motor armature and brake said inertia load; and a short circuit mode wherein the generator is short-circuited; and control means selectively actuable to connect said connecting means in one of said power and brake modes, said control means including means to, upon selection of the brake mode, first connect said connecting means for a predetermined brief period in the short circuit mode to quickly reduce residual generator voltage and to thereafter connect the connecting means in the brake mode.
Claim 3
Dependent Claim
64 words
The arrangement of claim 1 wherein said control means includes a first switch operable to place said connecting means in the power mode, a second switch operable to override said first switch and to place said connecting means in the brake mode and short circuit means arranged to temporarily place said connecting means in the short circuit mode upon actuation of said second switch.
Claim 4
Dependent Claim
75 words
The arrangement of claim 2 wherein said connecting means includes a contactor adapted to complete the short circuit of said generator when closed during said brake mode and said short circuit means comprises a time-delay relay arranged to maintain said contactor closed for a brief interval after said second switch is operated to select the brake mode and to subsequently act to open said contactor so as to complete the change to the brake mode.
Claim 5
Dependent Claim
187 words
An electric drive and dynamic braking arrangement for a vehicle having a power source and drive wheel means, said arrangement comprising: a generator; a traction motor having an armature and field windings and connectable with said drive wheel means for driving and braking said vehicle; resistance grid means for absorbing power; connecting means to interconnect said components in one of three modes, namely: a power mode wherein said generator supplies current to said motor for driving said vehicle; a brake mode wherein said generator supplies current to said motor field windings and said motor armature is connected to said resistance grid means to dissipate power geneRated by said motor armature and brake said inertia load; and a short circuit mode wherein said generator is short-circuited; and control means selectively actuable to connect said connecting means in one of said power and brake modes, said control means including means to, upon selection of the brake mode, first connect said connecting means for a predetermined brief period in the short circuit mode to quickly reduce residual generator voltage and to thereafter connect the connecting means in the brake mode.
Claim 6
Dependent Claim
187 words
An electric drive and dynamic braking arrangement for a vehicle having a power source and drive wheel means, said arrangement comprising: a generator; a traction motor having an armature and field windings and connectable with said drive wheel means for driving and braking said vehicle; resistance grid means for absorbing power; connecting means to interconnect said components in one of three modes, namely: a power mode wherein said generator supplies current to said motor for driving said vehicle; a brake mode wherein said generator supplies current to said motor field windings and said motor armature is connected to said resistance grid means to dissipate power geneRated by said motor armature and brake said inertia load; and a short circuit mode wherein said generator is short-circuited; and control means selectively actuable to connect said connecting means in one of said power and brake modes, said control means including means to, upon selection of the brake mode, first connect said connecting means for a predetermined brief period in the short circuit mode to quickly reduce residual generator voltage and to thereafter connect the connecting means in the brake mode.
Claim 7
Dependent Claim
64 words
The arrangement of claim 4 wherein said control means includes a first switch operable to place said connecting means in the power mode, a second switch operable to override said first switch and to place said connecting means in the brake mode and short circuit means arranged to temporarily place said connecting means in the short circuit mode upon actuation of said second switch.
Claim 8
Dependent Claim
75 words
The arrangement of claim 5 wherein said connecting means includes a contactor adapted to complete the short circuit of said generator when closed during said brake mode and said short circuit means comprises a time-delay relay arranged to maintain said contactor closed for a brief interval after said second switch is operated to selected the brake mode and to subsequently act to open said contactor so as to complete the change to the brake mode.
Claim 9
Independent Claim
153 words
The method of operating an electric drive and braking arrangement of the type having a generator, a drive motor having an armature and field windings and connected with an inertia load, resistance grid means and connecting means to interconnect said components in either of two modes, namely: a power mode wherein said generator supplies current to said motor for driving the inertia load, and a brake mode wherein said generator supplies current to said motor field windings and said motor armature is connected to said resistance means to dissipate power generated by said motor armature and brake said inertia load, said operating method comprising the step of momentarily short-circuiting the generator without generator excitation to reduce residual generator voltage while in process of changing the component connections from the power mode to the brake mode so as to permit a rapid change from power to brake modes without overexcitation of the drive motor.
Claim 10
Independent Claim
153 words
The method of operating an electric drive and braking arrangement of the type having a generator, a drive motor having an armature and field windings and connected with an inertia load, resistance grid means and connecting means to interconnect said components in either of two modes, namely: a power mode wherein said generator supplies current to said motor for driving the inertia load, and a brake mode wherein said generator supplies current to said motor field windings and said motor armature is connected to said resistance means to dissipate power generated by said motor armature and brake said inertia load, said operating method comprising the step of momentarily short-circuiting the generator without generator excitation to reduce residual generator voltage while in process of changing the component connections from the power mode to the brake mode so as to permit a rapid change from power to brake modes without overexcitation of the drive motor.
Claim 11
Dependent Claim
43 words
The method of claim 7 wherein the stop of short-circuiting the generator is initiated concurrently with the step of connecting the components in the brake mode such that when the short circuit is broken, the components will remain connected in the brake mode.
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |