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Description  |
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BACKGROUND OF THE INVENTION
This invention relates in general to electrical controls and in particular
to devices, systems and methods for controlling the supply of power to an
electrical load.
One of the problems confronting some electrical utility companies is the
peaking type-demands placed on their power generating equipment during
some summer months by the wide spread usage of air conditioning apparatus
particularly on rather hot days, and of course, other electrical utility
companies are confronted with such peaking-type demands during some winter
months due to the wide spread usage of electrical heating apparatus for
dwellings as well as auxiliary electrical loads, such as water heaters for
instance. In order to accommodate the peaking-type demands, electrical
utility companies would ordinarily be forced into rather large
expenditures for additional power generating capacity and equipment, but
of course, such expenditures appear unattractive since such peaking-type
demands presently may occur on an infrequent basis, i.e., generally only
between 15 to 30 days a year.
In the past, various devices were utilized in different systems and
different methods were employed to predeterminately limit the peaking-type
demands on the power generating capacity of the electrical utility
companies; however, one of the disadvantageous or undesirable features of
at least some of such prior art devices is believed to be that they were
generally much too complex both in design and operation so as to incur the
resultant disadvantageous or undesirable feature of being generally too
expensive for wide spread commercial usage in a power distribution system
or network.
In some of the other prior art devices, electromechanical components were
employed generally having at least some of the known disadvantageous or
undesirable features which may be attendent to such components. Others of
the prior art devices and systems utilize a radio-type signal emanated
from the utility company to disconnect their power customers' loads from
the power line; however, at least one of the disadvantageous or
undesirable features of this particular prior art device and system is
believed to be that the customers' loads may be disconnected for an
inordinately long period of time at the whim of the utility company
causing inconvenience and/or uncomfortable conditions for such customers.
Also such radio actuated prior art devices and systems possibly could be
undesirably actuated by a spurious signal. In still some others of the
prior art devices and systems, a ripple signal is emanated from the
utility company through their power network lines to disconnect their
power customers' loads from the power line; however, at least one of the
disadvantageous or undesirable features of this particular ripple signal
device and system is believed to be that only certain segments of the
power network may be taken off the line effecting inconvenience and/or
uncomfortable conditions to the power customer in such certain segment
while the other power customers' loads may be unaffected.
In another one of the prior art devices, the theory of its operation is
generally based upon preconceived or predicted periods during which
peaking-type demands were known to occur in the past. A photocell device
is responsive generally to the first light of day for actuating a timer
which, in effect, sets the prior art device to be operative only during
the predicted period of peaking-type demands for taking the regulated load
off the line. This prior art device is also provided with an atmospheric
temperature sensing mechanism which is operable generally to take the load
off the line if the sensed atmospheric temperature exceeds a selected
value when such prior art device is set to operate during the predicted
period. The load thereafter is off the line until the sensed atmospheric
temperature falls below the selected value thereof and/or until the time
of the predicted period of the peaking-type demand passes for that
particular day.
An improvement over such prior art devices and systems is disclosed in my
copending application Ser. No. 641,331 filed Dec. 16, 1975, now U.S. Pat.
No. 4,020,358 issued Apr. 26, 1977, which discloses a time proportioning
control for rationing power supplied to a load. In this patent, timing
signals are established upon the occurrence of preselected criteria of a
monitored condition, and a counter counts the established timing signals
and provides an output upon reaching a predetermined count. Logic
circuitry is responsive to the joint occurrence of an output signal and
the continued existence of the preselected criteria of the monitored
condition to inhibit the supply of electrical energy to the load.
SUMMARY OF THE INVENTION
Among the several objects of the present invention may be noted the
provision of devices, methods and systems for controlling the supply of
power to at least one load which overcome the above discussed
disadvantageous features, as well as others, of the prior art; the
provisions of such devices, methods and systems in which the inhibiting of
the power supplied to the load may be overriden under certain conditions;
the provision of such devices having a timing mechanism which can be reset
to the correct time through connection with a portable, plug-in type
service module; the provision of such devices, methods and systems having
no moving parts; and the provision of such devices, methods and systems
characterized by simplistic design, ease of assembling components
therefor, and economy of manufacture and use. These as well as other
objects and advantageous features of the present invention will be in part
apparent and in part pointed out hereinafter.
In general, a device in one form of the invention is provided for
controlling the supply of power to at least one electrical load. In this
device, means is provided for timing through at least one predetermined
time period. A pair of means are provided for monitoring a pair of
conditions, and means for inhibiting the supply of power to the at least
one load is operative when the monitored conditions meet preselected
criteria therefor, respectively, only during a preselected time range
within the at least one predetermined time period.
Still in general and in one form of the invention, a system is provided for
controlling the supply of electrical energy from a source thereof to an
electrical load. In this system, first means is provided for counting
timing signals applied thereto and to sequentially increment a stored
count of the timing signals to produce digital electric timing signals
whose value is representative of the time of day. Digital processing means
is responsive to the digital electric timing signals for producing digital
electric time interval signals having unique values during the occurrence
of at least one predetermined time interval during the day. Outdoor
temperature sensing means produces a digital electrical outdoor
temperature signal having a unique value when the sensed outdoor
temperature is within a predetermined outdoor temperature range, and
indoor temperature sensing means produces a digital electrical indoor
temperature signal having a unique value when the sensed indoor
temperature is within a predetermined indoor temperature range. Power
demand inhibiting means is responsive to the presence of the respective
time interval, indoor temperature and outdoor temperature signals of the
aforesaid unique values for producing a demand control signal adapted to
inhibit the supply of electrical energy to the load during the at least
one predetermined time interval solely when both the indoor temperature
and the outdoor temperature are within the predetermined ranges thereof.
Also in general and in one form of the invention, a system is provided for
controlling the supply of power from an alternating current source thereof
to at least one electrical load. In this system, means is operable
generally in response to repetitive timing signals supplied thereto for
counting through a plurality of predetermined time periods, and means is
provided for connecting the counting means with the power source so that
the alternating current thereof constitutes the timing signals. Means is
provided for monitoring a condition, and means is connected in circuit
relation with the counting means and the monitoring means for inhibiting
the supply of power from the source thereof to the at least one electrical
load when the monitored condition attains a preselected criteria therefor
during at least one selected part of selected ones of the predetermined
time periods.
Further in general, a method in one form of the invention is provided for
controlling the supply of power to an electrical load. In this method, the
steps include: counting timing signals through a predetermined time period
with the timing signals comprising an alternating current source thereof
and establishing a preselected range of time within at least a portion of
the predetermined time period and monitoring an ambient condition during
the predetermined time period; and inhibiting the supply of power to the
load when the monitored condition attains preselected criteria therefor
only during the preselected time range.
Still in general and in one form of the invention, another method is
provided for controlling the supply of power to at least one electrical
load. This method includes the steps of: timing through at least one
predetermined time period and monitoring a pair of conditions during the
at least one predetermined time period; and inhibiting the supply of power
to the at least one load when the monitored conditions each meet
preselected criteria therefor only during a preselected part of the at
least one predetermined time period.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a functional block diagram illustrating a device and system for
controlling the supply of power to a load in one form of the invention,
respectively, and also teaching principles of methods in one form of the
invention for controlling the supply of power to the load;
FIGS. 2a, 2b and 2c when joined together illustrate a detailed schematic
diagram of the device of FIG. 1.
FIG. 3 is a schematic diagram of a service module for plug-in connection
with the device of FIG. 1; and
FIG. 4 is a schematic diagram in greater detail of the service module of
FIG. 3.
Corresponding reference characters illustrate corresponding parts
throughout the several views of the drawings.
The exemplifications set out herein illustrate the preferred embodiments of
the invention in one form thereof, and such exemplifications are not to be
construed as limiting, in any manner, the scope of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the block diagram of FIG. 1, a method in one form of the
invention is illustrated for controlling the supply of power from a source
11 thereof to at least one electrical load, such as space heating
apparatus 13 of an electrical utility company's customer. In this method,
generally uniform repetitive timing signals constituted by a 60-cycle
alternating current of a source thereof (not shown) are counted so as to
establish a predetermined time period, such as for instance a daily or 24
hour period of time, and an ambient condition, such as atmospheric
temperature for instance, is monitored during the predetermined time
period. The supply of power from source 11 to load 13 is inhibited or
interrupted only if the monitored condition attains a preselected criteria
therefor during at least one preselected part of the predetermined time
period.
More particularly, means for timing through the predetermined time period
is indicated generally at 15 and includes means, such as an electronic
clock 17 of a type known to the art, for counting the timing signals.
Counting means or clock 17 is operable generally in response to the timing
signals supplied thereto to provide output signals on a line 19 which are
indicative of instantaneous time during the predetermined time period, and
the components of the clock may be selectively interconnected so as to
attain the aforementioned preselected part, such as any desired increment
of time or time range, of the predetermined time period, as discussed in
detail hereinafter. During the predetermined time period, condition
responsive means or monitoring means, such as a temperature sensitive
impedance device or sensor 21, senses or monitors the atmospheric or
outdoor temperature, and upon the occurrence of a preselected criteria or
temperature value of the outdoor temperature, such as for instance a value
of 24.degree. F., the sensor provides an output signal on line 23. Lines
19, 23 are both connected with means, such as logic circuitry 25, for
inhibiting the supply of power to load 13, and the inhibiting means or
logic circuitry is operable generally in response to the output signals of
the sensor and counting means 17 to actuate a load power switch or
contactor 27 to a switching position so as to interrupt the supply of
power to the load but only when the preselected criteria of the monitored
condition prevails during the preselected part of the predetermined time
period.
In FIG. 1, there is also illustrated another method in one form of the
invention for controlling the supply of power to load 13. This method
includes timing through the predetermined time period, monitoring a pair
of conditions, and inhibiting the supply of power to load 13 only if both
of the monitored conditions meet respective preselected criteria therefor
during the selected part of the predetermined time period.
More particularly, counting means 17, sensor 21 and logic circuitry 25 are
interconnected and operate in the same manner as previously described, and
one of the pair of monitored conditions is the outdoor temperature or
another ambient condition sensed by the sensor 21, as also previously
discussed. The other of the pair of monitored conditions is the indoor
temperature of the space being heated by the load or space heating
apparatus 13, and such indoor temperature is sensed or monitored by
condition responsive means or monitoring means, such as a temperature
sensitive impedance device or sensor 29, which is connected by a line 31
to logic circuitry 25. In the event the indoor temperature is above its
preselected criteria or temperature value, say for instance 60.degree. F.,
sensor 29 provides an output signal on line 31 which is, of course,
transmitted to logic circuitry 25. Logic circuitry 25 is operable
generally in response to the output signals of counting means 17 and
sensors 21, 29 so as to interrupt the supply of power to load 13 but only
if the monitored conditions of both the outdoor and indoor temperatures
meet their respective preselected criteria during the aforementioned
preselected part of the predetermined time period. In this manner, it may
be noted that when the indoor temperature falls below its 60.degree. F.
preselected value, an output signal indicative thereof is transmitted by
sensor 29 to logic circuitry 25 and causes it to override any output
signal received from sensor 21 in the event the outdoor temperature has
attained its 24.degree. F. preselected value. Therefore, due to this
override function or action of sensor 29, logic circuitry 25 operates to
maintain the power supply to load 13 until the indoor temperature of the
heated space is elevated through a preselected temperature differential or
range of sensor 21 to about 70.degree. F. This temperature differential of
sensor 21 is due to hysteresis in the circuitry thereof. At this time,
logic circuitry 25 is operable in response to counting means 17 and
sensors 21, 29 to actuate power switch 27 and interrupt the supply of
power to load 13, as previously described.
Other loads indicated generally at 33, such as for instance an electric
motor heater and/or an electric clothes dryer or other selected electrical
appliances, are connected with power source 11 through a power switch or
contactor 35 and also with logic circuitry 25. Logic circuitry 25 is also
operable in response to counting means 17 and sensors 21, 29, when the
monitored conditions meet the respective criteria therefor during the
selected part of the predetermined time period, to actuate power switch 35
to a switching position interrupting the supply of power from source 11 to
other loads 33. Further, it may be noted that logic circuitry 25 is
effective to maintain other loads 33 off the line irrespective of the
energization of load 13 when sensor 29 operates to cause the logic
circuitry to override the output signals of counting means 17 and sensor
21, as discussed above.
While the operations of the components discussed above with respect to the
foregoing methods have been based on the predetermined time period which,
as previously mentioned, may be a daily or 24 hour period, it may be
desirable to effect such operations through a plurality of predetermined
time periods, such as a weekly basis for instance. To this end, timing
means 15 also includes a 7 day counter or counting means, such as a modulo
eight counter 37, which implements counting means 17 and is connected
between counting means 17 and logic circuitry 25 by a pair of lines 39,
41. Seven day counter 37 is incremented by an output signal on line 39
from counting means 17 at the end of each predetermined time period, i.e.,
every 24 hours for instance, so as to time through a plurality of the
predetermined time periods, such as a 7 day week for instance. In this
manner, counting means 17 transmits output signals indicative of the time
of day on line 19 to logic circuitry 25, and upon incrementation, as
discussed above, 7 day counter 37 transmits output signals indicative of
the day of the week to the logic circuitry. As discussed in detail
hereinafter, 7 day counter 37 may also be provided with a "skip-a-day"
feature so as to be effective during only selected ones of the
predetermined time periods, i.e., during week days when peak power demand
is most apt to be present on the distribution system of the electrical
utility company. Therefore, it is contemplated that seven day counter 37
may, in effect, make logic circuitry 25 nonresponsive to any output
signals from sensors 21, 29 on a Saturday or Sunday when peak power demand
is less likely to occur.
As previously discussed, counting means 17 is actuated in response to
timing signals constituted by the alternating current of a source thereof
(not shown), and such timing signals are transmitted to the counting means
on a line 39. However, in the event of a power failure or outage on the
distribution system of the electrical utility company, auxiliary means,
such as a charging circuit 45, for supply timing signals to counting means
17 may be provided, if desired, and such auxiliary means or charging
circuit includes a standby battery 47, a battery charger 49 and an
oscillator 51. Of course battery charger 49 maintains the charge on
battery 47 so as to enable oscillator 51 which provides timing signals to
counting means 17 in the event of a power outage or loss of the normal
60-cycle line timing source, as discussed in detail hereinafter.
In the event timing means 15 for any reason loses or gains time so as to be
out of diurnal synchronization, means for correcting the instantaneous
time during the predetermined time periods, such as a portable, plug-in
type service module 53, may be electrically associated with counting means
17 so as to correct the count thereof and conform its ouput signals on
line 19 to the correct instantaneous time and the output signals on line
41 to the proper day of the week, as discussed in detail hereinafter.
Referring now to FIGS. 1, 2a, 2b and 2c in general and recapitulating at
least in part with respect to the foregoing, there is illustrated
generally at 55 a device in one form of the invention for controlling the
supply of power from source 11 thereof to at least load 13, and the
components of such device, as discussed below, are adapted to be encased
or housed in a suitable casing or housing (not shown) therefor. Device 55
has timing means 15 operable generally in response to timing signals
supplied thereto for timing through the predetermined time period and
means, such as sensor 21, for monitoring a condition, such as the outdoor
temperature or another ambient condition. Means, such as logic circuitry
25, is provided for inhibiting the supply of power to at least load 13
when the monitored condition meets its preselected criteria, such as a
preselected temperature value for instance, during at least one
preselected part of the predetermined time period.
More particularly and with specific reference to FIGS. 2a, 2b and 2c, a
step-down type transformer 57 has a fused primary winding connected to an
electrical plug 60 for association with a standard 120 volt household
outlet or alternating current power source (not shown), and the
alternating current supplied by such source constitutes the timing
signals. Transformer 57 also has a 25 volt center tapped secondary winding
61 thereby to provide an energizing current for a relay coil 63 as well as
a regulated DC voltage which is half-wave rectified off the center tap of
the secondary winding. This regulated voltage is half-wave rectified by a
diode 65, filtered by a capacitor 67, and thereafter regulated by a
transistor 69, a resistor 71 and a zener diode 73 connected in a known
regulated power supply configuration. Timing pulses of 60 Hertz from
secondary winding 59 of transformer 57 at the cathode of a zener diode 75
are supplied by way of a resistor 77 to one input of a NOR gate 79. These
timing pulses are, of course, half-wave rectified by a diode 81 and are of
about a 10 volt amplitude due to the zener action of zener diode 75.
Standby battery 47 is continuously charged through a resistor 83 which
functions as a current limiting resistor. A pair of NOR gates 85, 87 along
with a capacitor 89 and a plurality of resistors 91, 93, 95 generally
constitute oscillator 51 which may be tuned to 60 Hertz by 93 which is of
the variable type. Oscillator 51 will remain in a non-oscillating
condition so long as the line voltage is performing the timing function
since the junction between a pair of resistors 99, 101 will continuously
supply a high or logical one signal to one of the inputs of NOR gate 85.
This high input may be about 9 volts under normal operating conditions;
however, in the event of the failure or loss of the line voltage, 60 Hertz
timing pulses or signals are not supplied by way of resistor 77 to NOR
gate 79. As a result, the regulated direct current supply is not available
from transistor 69, and a diode 103 prevents battery 47 from providing a
current flow to the voltage divider including resistors 99, 101.
Therefore, the upper input to NOR gate 85 is effectively grounded by way
of resistor 101, and the left input to NOR gate 79 is effectively grounded
through a resistor 105. A diode 107 effectively bypasses resistor 83, and
battery powered oscillation may now occur. The output of oscillator 51 is
passed through a NAND gate 109 which functions as an inverter and provides
isolation during normal operation when the line voltage is available.
To provide the aforementioned preselected time range or preselected part of
the predetermined time period, assume that the preselected time range is
chosen to be from 9:00 a.m. to 12:00 noon and/or from 5:00 p.m. to 9:00
p.m. for example. The nucleus of counting means 17 is an integrated
circuit or circuit means 111, the output of which is logically combined in
several NAND and NOR gates to provide a signal for indicating the
establishment of the preselected time range. A different logical
combination of the outputs of integrated circuit 111 would, of course,
provide desired signals for other preselected time ranges. Integrated
circuit 111 also provides outputs indicated generally on a line 113 by way
of a fifty pin connector to service module 53 when connected therewith for
displaying time of day. Integrated circuit 111 provides time of day
signals in a seven segment code as well known to the art; however, a day
of the week indication is not provided in the commercially available
integrated circuit 111 and is generated by counter 37.
As an example, the 9:00 a.m. commencement of the preselected time range
within the predetermined time period during which power supply inhibition
may occur is traced through integrated circuit 111 as follows. The digit 9
in the seven segment code requires the energization of segments a, b, c,
d, f, and g but not e, which segments may be identified on a display unit
115 of service module 53, as shown in FIG. 3, as well as being shown above
their respective pin numbers on integrated circuit 111. Outputs of a, c, d
are respectively connected to the inputs of a NAND gate 117 while the
outputs of g, f are connected to the inputs of a NAND gate 119, and the
output of d is connected to one input of a NAND gate 121 and also to one
input of a NAND gate 123. When the outputs a, c, d, f, g, are high, i.e.,
a logical one, a NOR gate 125 has two low inputs and a high output.
Segment b on integrated circuit pin number 6 is also high for the digit 9,
and these two high signals are supplied to NAND gate 123. Segment e, which
must be low for the digit 9, is connected to an input of a NAND gate 127,
the output of which is high and also supplied as the third input to NAND
gate 123, the output of which is low when the digit 9 exists. This low
outut from NAND gate 123 is supplied as one input to a NOR gate 129, the
other input of which is the p.m. signal from a flip-flop 131. Thus the
output of NOR gate 129 is high only at 9:00 a.m. When 9:00 a.m. arrives,
the output of NOR gate 129 goes high setting another flip-flop 133. While
only the signals for decoding the digit 9 in the seven segment code is
discussed above, other preselected time indications may be decoded in a
similar manner as is well known in the art; therefore, the other code
requirement for indicating the termination of the aforementioned
preselected time range is omitted for the sake of brevity.
When time advance causes integrated circuit 111 to switch from p.m. to a.m.
flip-flop 131 changes to its set state thereby to cause the upper input of
a NOR gate 135 to go high. NOR gate 135, a capacitor 137, a resistor 139
and a NOR gate 141 are connected as a "one shot" giving a short pulse as
an input to 7 day counter 37 thus advancing it by one. 7 day counter 37 is
a modulo 8 counter, as previously mentioned, having a binary output which
must be decoded for a decimal readout. Counter 37 is connected to count
from 0 through 6 representing the 7 days of the week, and when the output
reaches count 7 (all three output lines high), the counter is immediately
reset to count 0. When count 7 is indicated by counter 37, all three
binary output lines are high causing the output of a NAND gate 143 and
therefore also a K terminal input of another flip-flop 145 to be low. The
low output from NAND gate 143 also causes a NAND gate 147 to provide a
high signal as an input to a J terminal of flip-flop 145, and when the
next 60 Hertz synchronizing clock pulse arrives at flip-flop 145, it
changes state so that its Q terminal output goes high to reset counter 37.
Means, such as a pair of NAND gates 149, 151 are employed for precluding
operation of inhibiting means 25 during selected ones of the predetermined
time period, i.e., to distinguish weekdays from Saturday and Sunday which
correspond to counts or decimal outputs of 5 and 6, respectively, from
counter 37. Thus NAND gates 149 will provide a low output only when
counter 37 has a decimal 6 output, and NAND gate 151 will provide a low
output only when the counter is in its decimal 5 condition. At all other
times, the outputs of both NAND gates 149, 151 are high thereby to give a
low output from a NAND gate 153 for counts of 0 through 4 of counter 37
which correspond to weekdays.
On weekdays, the upper input of a NOR gate 155 is low, and during the
preselected time ranges of 9:00 a.m. to 12:00 a.m. and/or again at 5:00
p.m. through 9:00 p.m., the middle input of NOR gate 155 is low. Assuming
that the lower input of NOR gate 155 is low due to an indication that the
outdoor temperature is below 24.degree. F., NOR gate 155 provides a high
output to initiate the power supply inhibiting function. This high or
inhibit signal by way of a resistor 157 turns on a transistor 159, and
conduction through the transistor and a resis | | |
