US3911342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plug current sensor for traction motor
Assignee: AC MATERIAL HANDLING Corp 777 MANOR PARK DRIVE COLUMBUS OHIO 43228 A CORP OHIO
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Filing: 1974-08-05
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Granted: 1975-10-07
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Expires: 1994-08-05
Abstract
Abstract A vehicle driven by a d.c. traction motor engergized from a battery has plugging means to dynamically brake the motor, an armature diode in shunt to the motor armature, and a plug current sensor including a ferromagnetic shielding and current carrying link connected in series with the armature diode and having a transverse depression and a constricted portion of reduced cross sectional area and also including a reed relay for controlling the plugging means disposed in the depression so that its contacts are operated by the magnetic field concentrated in the constricted portion of the link to thereby increase the sensitivity of the current sensor and prevent erratic plugging.
Inventors
- 👤 Warren E Herwig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:38
CPC Classifications
H; H02; H02P; H02P3/00; H02P3/06; H02P3/08; H01; H01H; H01H71/00; H01H71/10; H01H71/12; H01H71/24; H01H71/2445
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
238 words
In a vehicle driven by a d.c. traction motor energized from a battery and having a time-ratio control for selectively varying the average voltage applied from said battery to said motor to thereby regulate the speed of said motor, a diode in shunt to the inductive path of said motor, and motor plugging means for actuating said time-ratio control to reduce the average voltage supplied by said battery to said motor and thereby dynamically brake the rotation of said motor, the improvement comprising plug current sensor means for sensing the magnitude of current flowing through said diode when said motor is acting as a generator including a ferromagnetic current carrying and shielding member having a generally U-shaped indentation therein and also having a constricted neck portion of reduced cross section defining one of the walls of said U-shaped indentation and being connected in series with said diode so that the current through said diode also flows through said neck portion and a reed switch having a hollow casing of insulating material enclosing a pair of cooperable contacts movable to make and break an electrical circuit and being adapted to control said motor plugging means and to operate said contacts when disposed in a magnetic field of predetermined magnetic flux density, said reed switch being positioned in said indentation adjacent said neck portion so that it is within the magnetic field generated by current flowing through said neck portion.
Claim 2
Dependent Claim
238 words
In a vehicle driven by a d.c. traction motor energized from a battery and having a time-ratio control for selectively varying the average voltage applied from said battery to said motor to thereby regulate the speed of said motor, a diode in shunt to the inductive path of said motor, and motor plugging means for actuating said time-ratio control to reduce the average voltage supplied by said battery to said motor and thereby dynamically brake the rotation of said motor, the improvement comprising plug current sensor means for sensing the magnitude of current flowing through said diode when said motor is acting as a generator including a ferromagnetic current carrying and shielding member having a generally U-shaped indentation therein and also having a constricted neck portion of reduced cross section defining one of the walls of said U-shaped indentation and being connected in series with said diode so that the current through said diode also flows through said neck portion and a reed switch having a hollow casing of insulating material enclosing a pair of cooperable contacts movable to make and break an electrical circuit and being adapted to control said motor plugging means and to operate said contacts when disposed in a magnetic field of predetermined magnetic flux density, said reed switch being positioned in said indentation adjacent said neck portion so that it is within the magnetic field generated by current flowing through said neck portion.
Claim 3
Dependent Claim
22 words
In the combination of claim 1 wherein said diode is an armature diode connected in shunt to the armature of said motor.
Claim 4
Dependent Claim
29 words
In the combination of claim 2 wherein said diode is a free wheeling diode connected in shunt to the series connection of said motor armature and motor field winding.
Claim 5
Dependent Claim
35 words
In the combination of claim 1 wherein said U-shaped indentation extends transversely of the length of said current carrying and shielding member and said constricted neck portion forms the bottom leg of said U-shaped indentation.
Claim 6
Dependent Claim
46 words
In the combination of claim 1 wherein said time-ratio control comprises a pulse width modulation system having an oscillator which determines the pulse frequency, and wherein said motor plUgging means reduces the frequency of the output pulses from said oscillator to smoothly dynamically brake said motor.
Claim 7
Dependent Claim
203 words
In a vehicle driven by a d.c. traction motor energized from a battery through a time-ratio control to regulate the average voltage supplied to said motor and having plugging means for operating said time-ratio control to reduce the average voltage supplied from said battery to said motor to dynamically brake said motor, the combination of a diode in shunt to the inductive motor path, a ferromagnetic current carrying and shielding member having a generally U-shaped section and also having a constricted neck portion of reduced cross section defining one of the walls of said U-shaped section and being connected in electrical series relation with said diode so that the current through said diode also flows through said neck portion, and a reed switch having a hollow casing of insulating material enclosing a pair of cooperable contacts which are operable to make and break an electrical circuit and are adapted to control said plugging means, said reed switch being adapted to operate said contacts when positioned in a magnetic field of predetermined magnetic flux density and being disposed within said U-shaped section adjacent said constricted neck portion so that it is within the magnetic field generated by the current flowing through said neck portion.
Claim 8
Dependent Claim
203 words
In a vehicle driven by a d.c. traction motor energized from a battery through a time-ratio control to regulate the average voltage supplied to said motor and having plugging means for operating said time-ratio control to reduce the average voltage supplied from said battery to said motor to dynamically brake said motor, the combination of a diode in shunt to the inductive motor path, a ferromagnetic current carrying and shielding member having a generally U-shaped section and also having a constricted neck portion of reduced cross section defining one of the walls of said U-shaped section and being connected in electrical series relation with said diode so that the current through said diode also flows through said neck portion, and a reed switch having a hollow casing of insulating material enclosing a pair of cooperable contacts which are operable to make and break an electrical circuit and are adapted to control said plugging means, said reed switch being adapted to operate said contacts when positioned in a magnetic field of predetermined magnetic flux density and being disposed within said U-shaped section adjacent said constricted neck portion so that it is within the magnetic field generated by the current flowing through said neck portion.
Claim 9
Dependent Claim
23 words
In the combination of claim 6 wherein said diode is an armature diode connected in shunt to the armature of said traction motor.
Claim 10
Dependent Claim
30 words
In the combination of claim 7 wherein said diode is a free wheeling diode connected in shunt to the series arrangement of the armature and field winding of said motor.
Claim 11
Dependent Claim
194 words
A control panel for a vehicle traction motor energized from a battery and having plugging means to dynamically brake said motor and electrical cables disposed adjacent said panel carrying currents which generate external magnetic fields, said control panel including the unitary assembly of a free wheeling diode for connection in parallel to the series arrangement of the armature and field winding of said motor, an armature diode for connection in shunt to the armature of said motor, and a plug current sensor including a reed relay for detecting when the current through one of said diodes reaches a predetermined magnitude for controlling said plugging means, said plug current sensor also including a ferromagentic shielding and current carrying link assembled on said panel so that it is in electrical series relation with one of said diodes and having a transverse depression therein and a constricted portion of reduced cross sectional area defining one of the walls of said depression, said reed relay being disposed in said depression so that its contacts are operated by the magnetic field generated by the current flowing through said link member and which field is concentrated in said constricted portion.
Claim 12
Dependent Claim
194 words
A control panel for a vehicle traction motor energized from a battery and having plugging means to dynamically brake said motor and electrical cables disposed adjacent said panel carrying currents which generate external magnetic fields, said control panel including the unitary assembly of a free wheeling diode for connection in parallel to the series arrangement of the armature and field winding of said motor, an armature diode for connection in shunt to the armature of said motor, and a plug current sensor including a reed relay for detecting when the current through one of said diodes reaches a predetermined magnitude for controlling said plugging means, said plug current sensor also including a ferromagentic shielding and current carrying link assembled on said panel so that it is in electrical series relation with one of said diodes and having a transverse depression therein and a constricted portion of reduced cross sectional area defining one of the walls of said depression, said reed relay being disposed in said depression so that its contacts are operated by the magnetic field generated by the current flowing through said link member and which field is concentrated in said constricted portion.
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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |