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Claims  |
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What is claimed is:
1. A multiple voltage electrical supply system continuously connected for
individually charging a plurality of battery supplies continuously
connected in series with one another to supply a plurality of load
circuits having differing d.c. input voltage requirements, said load
circuits also having differing expected electrical power consumption rates
such that one of said battery supplies is normally expected to draw less
charging current than the other of said battery supplies, said system
comprising:
an alternator structure including,
a stator means having salient poles of ferromagnetic material,
a rotor means magnetically coupled and rotably mounted with respect to said
stator means and shaped so as to cause variations of magnetic flux within
said salient poles in response to rotation thereof,
a field winding mounted to generate magnetic flux in said rotor and stator
means in response to electrical current flow in said field winding,
a first generating winding disposed upon said salient poles of a first
electrical conductor having a first characteristic resistance per unit
length and producing a first a.c. output therefrom in response to rotation
of said rotor means due to the magnetic flux variations produced thereby,
a second generating winding electrically isolated from said first winding,
said second winding also being disposed upon said salient poles so as to
insure that the magnetic flux linking said first generating winding bears
a substantially constant ratio to the magnetic flux linking said second
generating winding,
said second generating winding being formed of a second conductor having a
second characteristic resistance per unit length greater than said first
characteristic resistance per unit length thereby producing an increased
internal voltage drop in said second winding as compared to said first
winding for a given current flow, said second winding producing a second
a.c. output therefrom in response to rotation of said rotor structure due
to the magnetic flux variations produced thereby;
a first rectifier means continuously connected to said first generating
winding and converting said first a.c. output into a corresponding first
d.c. output which is, in turn, continuously connected to provide charging
current to the said other of said battery supplies requiring the
relatively greater expected charging current;
a second rectifier means continuously connected to said second generating
winding and converting said second a.c. output into a corresponding second
d.c. output which is, in turn, continuously connected to provide charging
current to the said one of said battery supplies requiring the relatively
smaller expected charging current; and
a single voltage regulator connected to sense the voltage at one of said
first and second d.c. outputs an also connected to control the current
flow in said field winding so as to maintain the voltage at said selected
one of the d.c. outputs at a desired level and thereby also substantially
maintain the voltage at the remaining d.c. output at a corresponding
desired voltage level as a result of the relatively greater expected
current to be drawn from said first generating winding and the increased
internal voltage drop in said second generating winding as compared to
said first generating winding for a given current flow due to the
increased internal winding resistance of said second generating winding as
compared to said first generating winding.
2. A multiple voltage electrical supply system as in claim 1 wherein:
said first generating winding comprises a three-phase winding producing a
three-phase first a.c. output;
said second generating winding comprises a single phase winding producing a
single phase second a.c. output; said first rectifier means comprises a
three-phase full wave rectifier; and
said second rectifier means comprises a single phase full wave rectifier.
3. A multiple voltage electrical supply system as in claim 1 wherein:
said first and second generating means are each three-phase windings
producing three-phase first and second a.c. outputs respectively; and
said first and second rectifier means are each three-phase full wave
rectifiers.
4. A multiple voltage electrical supply system for use with a plurality of
load circuits having differing d.c. input voltage requirements, said
system comprising:
an alternator having a plurality of sets of generating windings producing a
corresponding plurality of a.c. output voltages,
at least one of said sets of generating windings being formed of
differently sized conductors than another of said sets of generating
windings,
a plurality of rectifiers, each continuously connected with a respective
one of said sets of generating windings, for rectifying said plurality of
a.c. output voltages into a corresponding plurality of d.c. voltages,
a plurality of batteries continuously connected in series with one another,
each of said batteries having two terminals,
a plurality of load circuits continuously connected across different pairs
of said terminals of said series connected batteries so as to receive
different d.c. voltages from said batteries,
conductor means continuously connecting each of said plurality of d.c.
voltages from said plurality of rectifiers across two respectively
associated terminals of an individual respectively associated one of said
batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said sets of generating windings and also having a field coil,
the degree of excitation of which controls the total amount of magnetic
flux passing through said core and the amplitude of the a.c. voltages
induced in the windings of said sets of windings,
said windings being mounted on said core in such a manner that a
substantially constant ratio of magnetic flux magnetically links each of
the sets of windings when compared to one another, and
a single voltage regulator means responsive to the electrical output from a
corresponding single one of said sets of generating windings for
controlling the excitation of said field coil and maintaining the
electrical output voltages from all of said sets of generating windings at
substantially constant values without changing any electrical
interconnections between said winding, rectifiers, batteries or load
circuits
the relative construction, size and disposition of said sets of generating
windings being effective to automatically maintain substantially constant
output voltages from all sets of generating windings in response to
regulation from said single voltage regulator means while, at the same
time, automatically varying the charging current produced from said sets
of generating windings as required by the respectively corresponding
connected batteries.
5. A multiple voltage electrical supply system as defined in claim 4
further characterized by each winding of one of said sets having a
corresponding winding in each of the other sets and said ferromagnetic
core of said alternator including a plurality of salient poles,
corresponding windings of said sets of generating windings being mounted
on the same one of said salient poles.
6. A dual voltage electrical system comprising:
an alternator having a first set of generating windings producing a first
a.c. output voltage and also having a second set of generating windings
electrically isolated from said first set of windings and producing a
second a.c. output voltage:
said first set of generating windings being formed of differently sized
conductors than said second set of generating windings,
a first rectifier for rectifying said first a.c. output voltage into a
first d.c. voltage, said first rectifier having first and second output
terminals across which said first d.c. voltage appears,
a second rectifier for rectifying said second a.c. output voltage into a
second d.c. voltage, said second rectifier having third and fourth output
terminals across which said second d.c. voltage appears,
said second and third terminals being of opposite polarity,
conductor means electrically connecting said second and third terminals to
one another continuously at a common point,
a first battery continuously connected between said first terminal and said
common point,
a second battery continuously connected between said common point and said
fourth terminal,
a service load circuit connected across said first terminal and said common
point so as to be in parallel with said first battery,
a second load circuit requiring a higher input voltage than said service
load circuit connected across said first and fourth terminals so as to be
connected in parallel with the series combination of said two batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said first and second sets of generating windings and also having
a field coil,
each winding of one of said sets having a corresponding winding in the
other of said sets and each winding and its corresponding winding being
mounted on said core in such a manner that substantially all of the
magnetic flux which passes through any one winding also passes through its
corresponding winding and so that the voltage induced in one winding has a
fixed ratio to the voltage induced in its corresponding winding, and
a single voltage regulator responsive to the d.c. output voltage appearing
across the two output terminals of one of said two rectifiers for
controlling the excitation of said field coil to maintain said latter d.c.
output voltage at a substantially constant value
the relative construction, size and disposition of said sets of generating
windings being effective to automatically maintain substantially constant
output voltages from all sets of generating windings in response to
regulation from said single voltage regulator means while, at the same
time, automatically varying the charging current produced from said sets
of generating windings as required by the respectively corresponding
connected batteries.
7. A dual voltage electrical system as defined in claim 6 further
characterized by said core having a plurality of salient poles each of
which receives one of said windings of said first set of generating
windings and its corresponding winding of said second set.
8. A dual voltage electrical system as defined in claim 6 further
characterized by an internal combustion engine for driving said
alternator, an electrical starter motor for starting said engine, and at
least one electrically powered accessory associated with said engine, said
accessory comprising at least a part of said service load circuit and said
starter motor comprising at least a part of said second load circuit.
9. A multiple voltage electrical supply system for use with a plurality of
load circuits having differing d.c. input voltage requirements, said
system comprising:
an alternator having a plurality of sets of generating windings producing a
corresponding plurality of a.c. output voltages,
a plurality of rectifiers, each continuously connected with a respective
one of said sets of generating windings, for rectifying said plurality of
a.c. output voltages into a corresponding plurality of d.c. voltages,
a plurality of batteries continuously connected in series with one another,
each of said batteries having two terminals,
a plurality of load circuits continuously connected across different pairs
of said terminals of said series connected batteries so as to receive
different d.c. voltages from said batteries,
conductor means continuously connecting each of said plurality of d.c.
voltages from said plurality of rectifiers across two respectively
associated terminals of an individual respectively associated one of said
batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said sets of generating windings and also having a field coil,
the degree of excitation of which controls the total amount of magnetic
flux passing through said core and the amplitude of the a.c. voltages
induced in the windings of said sets of windings,
said windings being mounted on said core in such a manner that a
substantially constant ratio of magnetic flux magnetically links the sets
of windings,
a single voltage regulator means responsive to the electrical output from a
corresponding single one of said sets of generating windings for
controlling the excitation of said field coil and maintaining the
electrical output voltages from all of said sets of generating windings at
substantially constant values without changing any electrical
interconnections between said windings, rectifiers, batteries or load
circuits,
each winding of one of said sets having a corresponding winding in each of
the other sets and said ferromagnetic core of said alternator including a
plurality of salient poles, corresponding windings of said sets of
generating windings being mounted on the same one of said salient poles,
and
said alternator being an inductor alternator wherein said field coil, said
core and said sets of generating windings are stationary relative to one
another, said inductor alternator including a part of ferromagnetic
material rotatable relative to said core for varying the reluctance of the
flux paths through said salient poles of said core to in turn vary the
amount of flux passing through said salient poles and the voltages induced
in the windings on said poles.
10. A multiple voltage electrical supply system for use with a plurality of
load circuits having differing d.c. input voltage requirements, said
system comprising:
an alternator having a plurality of sets of generating windings producing a
corresponding plurality of a.c. output voltages,
a plurality of rectifiers, each continuously connected with a respective
one of said sets of generating windings, for rectifying said plurality of
a.c. output voltages into a corresponding plurality of d.c. voltages,
a plurality of batteries continuously connected in series with one another,
each of said batteries having two terminals,
a plurality of load circuits continuously connected across different pair
of said terminals of said series connected batteries so as to receive
different d.c. voltages from said batteries,
conductor means continuously connecting each of said plurality of d.c.
voltages from said plurality of rectifiers across two respectively
associated terminals of an individual respectively associated one of said
batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said sets of generating windings and also having a field coil,
the degree of excitation of which controls the total amount of magnetic
flux passing through said core and the amplitude of the a.c. voltages
induced in the windings of said set of windings,
said windings being mounted on said core in such a manner that a
substantially constant ratio of magnetic flux magnetically links the sets
of windings,
a single voltage regulator means responsive to the electrical output from a
corresponding single one of said sets of generating windings for
controlling the excitation of said field coil and maintaining the
electrical output voltages from all of said sets of generating windings at
substantially constant values without changing any electrical
interconnections between said windings, rectifiers, batteries or load
circuits,
each winding of one of said sets having a corresponding winding in each of
the other sets and said ferromagnetic core of said alternator including a
plurality of salient poles, corresponding windings of said sets of
generating windings being mounted on the same one of said salient poles,
and
said corresponding windings of said sets being wound in multifilar
relationship with one another.
11. A multiple voltage electrical supply system for use with a plurality of
load circuits having differing d.c. input voltage requirements, said
system comprising:
an alternator having a plurality of sets of generating windings producing a
corresponding plurality of a.c. output voltages,
a plurality of rectifiers, each continuously connected with a respective
one of said sets of generating windings, for rectifying said plurality of
a.c. output voltages into a corresponding plurality of d.c. voltages,
a plurality of batteries continuously connected in series with one another,
each of said batteries having two terminals,
a plurality of load circuits continuously connected across different pairs
of said terminals of said series connected batteries so as to receive
different d.c. voltages from said batteries,
conductor means continuously connecting each of said plurality of d.c.
voltages from said plurality of rectifiers across two respectively
associated terminals of an individual respctively associated one of said
batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said sets of generating windings and also having a field coil,
the degree of excitation of which controls the total amount of magnetic
flux passing through said core and the amplitude of the a.c. voltages
induced in the windings of said sets of windings,
said windings being mounted on said core in such a manner that a
substantially constant ratio of magnetic flux magnetically links the sets
of windings,
a single voltage regulator means responsive to the electrical output from a
corresponding single one of said sets of generating windings for
controlling the excitation of said field coil and maintaining the
electrical output voltages from all of said sets of generating windings at
substantially constant values without changing any electrical
interconnections between said windings, rectifiers, batteries or load
circuits,
each winding of one of said sets having a corresponding winding in each of
the other sets and said ferromagnetic core of said alternator including a
plurality of salient poles, corresponding windings of said sets of
generating windings being mounted on the same one of said salient poles,
and
each of said sets of generating windings including three groups of windings
in which electrical voltages of different phases are induced, the three
groups of windings of each set being connected to one another to produce a
three-phase a.c. output voltage, and each of said rectifiers being a
three-phase rectifier for rectifying the three-phase a.c. voltage from the
associated set of generating windings into a d.c. voltage.
12. A dual voltage electrical system comprising: an alternator having a
first set of generating windings producing a first a.c. output voltage and
also having a second set of generating windings electrically isolated from
said first set of windings and producing a second a.c. output voltage,
a first rectifier for rectifying said first a.c. output voltage into a
first d.c. voltage, said first rectifier having first and second output
terminals across which said first d.c. voltage appears,
a second rectifier for rectifying said second a.c. output voltage into a
second d.c. voltage, said second rectifier having third and fourth output
terminals across which said second d.c. voltage appears,
said second and third terminals being of opposite polarity,
conductor means electrically connecting said second and third terminals to
one another continuously at a common point,
a first battery continuously connected between said first terminal and said
common point,
a second battery continuously connected between said common point and said
fourth terminal,
a service load circuit connected across said first terminal and said common
point so as to be in parallel with said first battery,
a second load circuit requiring a higher input voltage than said service
load circuit connected across said first and fourth terminals so as to be
connected in parallel with the series combination of said two batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said first and second sets of generating windings and also having
a field coil,
each winding of one of said sets having a corresponding winding in the
other of said sets and each winding and its corresponding winding being
mounted on said core in such a manner that substantially all of the
magnetic flux which passes through any one winding also passes through its
corresponding winding and so that the voltage induced in one winding has a
fixed ratio to the voltage induced in its corresponding winding, and
a single voltage regulator responsive to the d.c. output voltage appearing
across the two output terminals of one of said two rectifiers for
controlling the excitation of said field coil to maintain said latter d.c.
output voltage at a substantially constant value,
said windings of said first set windings being in bifilar relationship with
the corresponding windings of said second set of windings.
13. A dual voltage electrical system comprising:
an alternator having a first set of generating windings producing a first
a.c. output voltage and also having a second set of generating windings
electrically isolated from said first set of windings and producing a
second a.c. output voltage,
a first rectifier for rectifying said first a.c. output voltage into a
first d.c. voltage, said first rectifier having first and second output
terminals across which said first d.c. voltage appears,
a second rectifier for rectifying said second a.c. output voltage into a
second d.c. voltage, said second rectifier having third and fourth output
terminals across which said second d.c. voltage appears,
said second and third terminals being of opposite polarity,
conductor means electrically connecting said second and third terminals to
one another continuously at a common point,
a first battery continuously connected between said first terminal and said
common point,
a second battery continuously connected between said common point and said
fourth terminal,
a service load circuit connected across said first terminal and said common
point so as to be in parallel with said first battery,
a second load circuit requiring a higher input voltage than said service
load circuit connected across said first and fourth terminals so as to be
connected in parallel with the series combination of said two batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said first and second sets of generating windings and also having
a field coil,
each winding of one of said sets having a corresponding winding in the
other of said sets and each winding and its corresponding winding being
mounted on said core in such a manner that substantially all of the
magnetic flux which passes through any one winding also passes through its
corresponding winding and so that the voltage induced in one winding has a
fixed ratio to the voltage induced in its corresponding winding, and
a single voltage regulator responsive to the d.c. output voltage appearing
across the two output terminals of one of said two rectifiers for
controlling excitation of said field coil to maintain said latter d.c.
output voltage at a substantially constant value,
said alternator being an inductor alternator wherein said ferromagnetic
core, said field coil and said two sets of generating windings are fixed
relative to one another and wherein changes in the magnetic flux passing
through said two sets of generating windings on said ferromagnetic core
are produced by a ferromagnetic part rotatable relative to said core.
14. A dual voltage electrical system comprising:
an alternator having a first set of generating windings producing a first
a.c. output voltage and also having a second set of generating windings
electrically isolated from said first set of windings and producing a
second a.c. output voltage,
a first rectifier for rectifying said first a.c. output voltage into a
first d.c. voltage, said first rectifier having first and second output
terminals across which said first d.c. voltage appears,
a second rectifier for rectifying said second a.c. output voltage into a
second d.c. voltage, said second rectifier having third and fourth output
terminals across which said second d.c. voltage appears,
said second and third terminals being of opposite polarity,
conductor means electrically connecting said second and third terminals to
one another continuously at a common point,
a first battery continuously connected between said first terminal and said
common point,
a second battery continuously connected between said common point and said
fourth terminal,
a service load circuit connected across said first terminal and said common
point so as to be in parallel with said first battery,
a second load circuit requiring a higher input voltage than said service
load circuit connected across said first and fourth terminals so as to be
connected in parallel with the series combination of said two batteries,
said alternator having a magnetic flux conducting ferromagnetic core
carrying said first and second sets of generating windings and also having
a field coil,
each winding of one of said sets having a corresponding winding in the
other of said sets and each winding and its corresponding winding being
mounted on said core in such a manner that substantially all of the
magnetic flux which passes through any one winding also passes through its
corresponding winding and so that the voltage induced in one winding has a
fixed ratio to the voltage induced in its corresponding winding,
a single voltage regulator responsive to the d.c. output voltage appearing
across the two output terminals of one of said two rectifiers for
controlling the excitation of said field coil to maintain said latter d.c.
output voltage at a substantially constant value, and
said first set of windings being made of conductor having a smaller
resistance per unit length than the conductor comprising said second set
of windings. |
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Claims |
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Description |
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This invention generally relates to a multiple voltage electrical supply
system for supplying a plurality of d.c. voltages. More particularly, it
relates to a multiple voltage electrical supply system of a type which is
especially useful for individually charging a plurality of battery
supplies in a vehicular or other electrical system associated with a prime
mover (i.e. a stationary power plant) which requires a first d.c.
operating voltage for a conventional "service load" (e.g. 12 volts for
lighting, instrumentation, etc.) and a higher second d.c. voltage for
operating a special load (e.g. 24 volts for a cranking motor). Typically,
a single 12 volt battery or two series connected six volt batteries are
utilized for supplying a twelve volt service load while two twelve volt
batteries connected in series or four six volt batteries connected in
series are utilized for supplying the 24 volt starter motor circuitry. The
12 volt service load may, of course, be supplied by two or more battery
supplies connected in parallel if desired.
Such dual voltage electrical systems have been used in some types of
vehicles for many years as the required cranking power for starting such
vehicles has increased. For a time, such requirements for a dual voltage
vehicle electrical system were minimized by attempts to design higher
powered output 12 volt starting motors. However, for various reasons,
there now appears to be an even greater demand for higher voltage cranking
motors and, as a consequence, the resulting dual voltage vehicular
electrical system.
Of course, the battery supply of d.c. voltage for such dual voltage systems
must be replenished by a suitable battery charging arrangement which, in
turn, obtains its energy input from a prime mover such as an internal
combustion engine which is often the same prime mover as that utilized by
the vehicle for locomotion. As will be appreciated by those in the art, it
is desirable to provide a single alternator or generator structure and to
have that single alternator or generator structure properly charge all of
the batteries in the system so as to maintain a required dual voltage
supply for the service load and the starting motor.
The most common practice in the past has been to provide a so-called
"series-parallel" switch arrangement whereby two twelve volt battery
supplies are normally connected in parallel for charging by a twelve volt
supply of charging current from an alternator or a generator structure
driven by the prime mover. The service load would, of course, also be
connected across the normally parallel connected batteries. However, in a
starting switch position, the "series-parallel" switch would reconnect the
batteries in series with the starter motor circuit so as to supply that
circuit with a higher 24 volts. As is recognized in the art, there are
many practical maintenance problems with such "series-parallel" switches
in part because of mechanical complexities of the switch, mechanical wear,
and the high electrical cranking currents that must be carried by the
electrical contacts of such a switch, etc.
Accordingly, there have been a number of prior suggestions for achieving
the desired dual voltage system without using the "series-parallel" switch
wherein the two twelve volt batteries involved in the dual voltage system
are permanently connected in series with one another and charged by a
generating system driven by the prime mover which provides two isolated
d.c. outputs supplying charging currents for the batteries. However, as
those in the art will also appreciate, reliable and effective practical
achievement of such a system is complicated by the fact that the battery
supplying the service load normally requires much higher charging currents
than the auxiliary battery which is normally used only during operation of
the starter motor and by the fact that these two unequal electrically
isolated charging currents must be produced by a single alternator or
generator structure since it is not considered desirable to mount two
completely separate alternator structures on the prime mover.
One prior art attempt to achieve such a dual voltage supply system without
the "series-parallel" switch is shown by U.S. Pat. No. 3,710,226 issued to
Seike, Jan. 9, 1973. Here, the three-phase generating winding of a
standard alternator has been reconnected such that only two phases are
utilized for supplying charging current to the main battery and the third
electrically isolated phase of the generating winding is output separately
to supply charging current for the auxiliary battery. The usual voltage
regulator is utilized for regulating the output voltage delivered to
charge the main battery by regulating the current through a field winding
of the alternator while a special solid state series regulator is utilized
for controlling the output charging voltage delivered to the auxiliary
battery. However, this prior art arrangement requires two separate voltage
regulator circuits and, in addition, necessarily increases the ripple
component of charging currents supplied to the two batteries since the
main battery is only supplied by two phases and the auxiliary battery is
supplied by but a single phase of the alternator generating windings.
Another prior art approach is shown by U.S. Pat. No. 3,816,805 issued to
Terry on June 11, 1974. In this prior art approach, one phase of the
three-phase electrical output from the alternator is also utilized to
energize the primary winding of an isolation transformer while the
secondary of the isolation transformer then provides an isolated source of
a.c. output which is rectified in a single phase full wave rectifier and
utilized for charging the auxiliary battery.
Still another prior art approach is shown by U.S. Pat. No. 3,793,544 issued
to Baumgartner et al on Feb. 19, 1974. Here, the usual three-phase
generating windings of the alternator have been duplicated to provide two
electrically isolated but otherwise identical sets of generating windings
in the same alternator structure. The two a.c. electrical outputs from
these isolated generating windings are then individually rectified and
utilized for supplying charging currents to the two s | | |
