Emergency supplemental power supply for outage protection of critical electric loads

An emergency supplemental power supply for outage protection of critical electric equipment load powered from a commercial power grid, including a first Variable speed drive, a second Variable speed drive, a first asynchronous motor powered from the first Variable speed drive for turning a fly-wheel attached thereto to ramp-up and maintain a level of expendable kinetic energy in the fly-wheel, the fly-wheel coupled to a first synchronous alternating current generator for driving the generator in a no-load, standby condition, a second asynchronous motor coupled to a second synchronous alternating current generator, in combination, and interposed the second Variable speed drive and the critical electric equipment load, a prime mover including a coupling between the prime mover to the second asynchronous motor/second synchronous alternating current generator combination, and, a computer processor interconnected all elements for maintaining the frequency of alternating current output from the first synchronous alternating current generator slightly above the frequency of the commercial power on the grid wherein, the emergency contactor, is arranged to close upon the sagging or outage of incoming grid power to the critical load and allow the kinetic energy in the rotating fly-wheel to drive the first synchronous alternating current generator and produce a decaying alternating current.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 This invention pertains to the field of emergency power systems. More
 particularly, it pertains to a rotary dynamo device that is close-coupled
 to a flywheel to provide instant short-term alternating current, with
 maintained voltage regulation, to critical electric loads that may include
 frequency tolerant devices.
 2. Description of the Prior Art
 Commercial electrical power available today is becoming unreliable due to
 the growing number of electrical loads placed on the electrical power
 grid. In addition, many of the new loads on the power grid are critical in
 their need for constant frequency and/or voltage. These loads are usually
 tolerant of a small change in frequency, however, they cannot tolerate an
 instantaneous loss of power without concomitant damage.
 For instance, some modern molding machines and metal-forming machines
 require constant power for sustained operation. They will tolerate only
 momentary and short-span variations in voltage and frequency, however,
 they cannot tolerate an unplanned, instantaneous, total loss of power.
 Should this occur, the molding machine will likely seize and possibly
 catch fire, from the high temperature material trapped in the mold, while
 the metal-forming machine will begin to spin down with the cutting tool
 remaining against the work piece and often will cause unplanned cutting on
 the work piece that destroys it. In the case of stand-alone computers and
 computer-driven machinery, the instantaneous and continuous loss of power
 may result in corruption of the computer files or loss of important
 program data.
 Momentary electrical outages, frequency or voltage fluctuation (sags and
 spikes), extended outages and questionable return of normal power to an
 electrical load are thus becoming common place. These electrical power
 problems affect all governmental, commercial, industrial and private
 sectors of society. These locations that are affected include but are not
 limited to National Security, Law Enforcement, Hospitals, Communication,
 (cellular, paging services, satellite data recovery sites, local telephone
 service, microwave and antenna repeater sites), Radio and Television
 Broadcasting, Commercial Data Centers and any other electrical load
 supported or backed up by the commercial electric grid.
 In order to ameliorate the potentially disastrous effects of such
 interruptions in commercial power to critical electric machines, an
 industry has grown up around a combination of electrical equipment that
 has, as its goal, the immediate implementation of supplemental alternating
 current to the electrical load. This supplemental alternating current must
 be frequency and voltage stable for a period of time varying from a few
 seconds, such as between about 8 seconds to 20 seconds, to a longer
 period, such as indefinitely or until the resumption of commercial power.
 In the short periods, such as 8 to 20 seconds, the critical machines enter
 a shut-down program designed to save the machine and the product produced
 by the machine. In longer periods, varying anywhere from 20 seconds to as
 much as hours or days, the load is serviced by the supplemental
 alternating current until the resumption of commercial power. In the case
 of the molding machines, the 8 to 20 second shut-down program would
 include the immediate opening of the mold and the expelling of the part
 being molded to free the machine from possible fire or lock-up by virtue
 of over-curing the material caught in the mold. In the case of
 metal-forming machines, the short shut-down program would be the immediate
 withdrawal of the cutting tool to preserve the work piece in its
 partially-formed configuration and then a shut down of the work piece
 drive motor. In the case of computers and computer-controlled machinery,
 the 8 to 20 second shutdown program would include the pre-programmed shut
 down of various subassemblies of the computer until the entire computer
 and processor are turned off resulting in saving data and preserving
 programs without corruption.
 Prior art equipment and systems designed to provide this supplemental
 alternating current utilize batteries to provide direct current that is
 inverted to alternating current. The alternating current produced by this
 inverted battery power keeps the equipment running, while fault notices
 coming from power monitors, immediately switch the critical loads into
 their respective shutdown programs to allow the equipment to later go
 off-line and shut down in an orderly fashion thereby preserving the
 equipment, work pieces and computer programs and data. The reason
 batteries are used as the prime source of power is that inverting direct
 current to 60 Hertz alternating current from a battery can be accomplished
 with an inverter.
 Unfortunately, battery-powered systems of this type are not popular for a
 number of reasons. First, batteries require a substantial capital
 investment that must be maintained by replacing batteries as they wear
 out, due to usage and just plain old age, usually on the average of every
 five years. Secondly, batteries are subject to boiling over, exploding,
 leaking, and other such maladies that require constant maintenance which
 raises the cost of having them in the power system. In addition, batteries
 must be located in ambient conditions that include a warm, dry atmosphere
 and this often requires a controlled environment, including heating and
 air conditioning equipment, that increases the overall cost of operation.
 Many manufacturing plants that need this type of protection are located in
 areas where harsh environmental conditions exist for at least part of the
 year. In these areas, batteries are not desired because these harsh
 conditions contribute to their instability and their early demise.
 The devices of this small but growing industry are often referred to as
 Uninterruptible Power Supply (UPS) systems. During an outage, this system,
 supported by an array of direct current batteries or a flywheel apparatus
 that replaces the direct current battery array, provides direct current
 power that is transformed into alternating current and fed into the power
 grid load for a short period of time, such as for 8 to 20 seconds in order
 for the critical electric load to undergo an orderly shutdown. Batteries
 cannot provide sustained power because of their limited capacity. However,
 in some cases, such as in momentary interruption of commercial power, this
 battery-powered UPS system will continue the alternating power to the load
 until commercial power is restored if the interruption is for only for a
 short duration. In other cases, the UPS system can be modified to provide
 a prime mover, such as a fossil fuel-driven engine driving an electric
 generator, to provide continuous alternating current to the load during
 periods of extended outages. However, in all these cases, batteries are
 the source of the instantaneous power fed to the load. In addition, these
 prior art devices are special built and use parts that must be specially
 ordered and manufactured leading to high costs and long ordering and
 reordering delays.
 Most electrical power grids have similar characteristics when they
 malfunction, including: sags (alternating current voltage decreases),
 surges (alternating current voltage increases), transients (alternating
 current voltage spikes caused by utility load sub-cycle switching),
 flickers or blinks (sub-second momentary alternating current voltage
 outage), momentary outages (alternating current voltage loss greater than
 1 second) and extended outages (alternating current voltages loss for an
 undetermined amount of time). An Uninterruptible Power Supply system is
 designed to protect against all these abnormalities by eliminating the
 instantaneous loss, sags, or surges or of power (identified as "outage"
 throughout the balance of this patent application) and substituting it
 with short-duration power of similar frequency and voltage in order to
 allow pre-programmed shutdown.
 The Uninterruptible Power Supply systems in the prior art are provided in
 two general designs: First, there is the Static UPS system that utilizes
 alternating current input and rectifies the electrical power to direct
 current. This direct current is used to charge the batteries for outage
 protection and supports the inverter to reconvert the direct current power
 to alternating current to supply the alternating electrical power for the
 load. Upon loss of input alternating current, the inverter is continuously
 supported by the direct current battery system until the battery system is
 depleted or normal alternating current is restored to the input of the
 Static UPS system. If the battery system is depleted prior to the
 restoration of normal alternating current power, the load will experience
 a loss of power and shutdown.
 Second, the Rotary UPS system utilizes an input to support the motor
 section of the system that rotates an alternating current generator to
 supply electrical power to the load. The Rotary UPS system may be
 supported by the following systems to insure outage protection:
 U.S. Pat. No. 4,243,598 discloses a direct current motor coupled directly
 to an alternating current motor and generator to maintain the nominal
 rotor shaft speed during an outage condition. The direct current motor is
 supported by a battery system as in the Static UPS system. It may also
 provide battery support for a Rotary UPS system.
 U.S. Pat. No. 4,827,152 discloses a directly coupled hydraulic motor that
 utilizes a high pressure hydraulic bladder system to maintain rotor shaft
 speed long enough to allow an engine to start and support the system rotor
 shaft speed. When normal power is restored, the system will continue to
 operate on the engine until the hydraulic bladder is replenished and ready
 for another outage condition.
 U.S. Pat. No. 5,811,960 discloses an alternating current generator coupled
 to a continuous power alternating current motor and further coupled to a
 flywheel to provide power to the systems internal direct current rectifier
 to support the rectifier when commercial input alternating current power
 is removed. The alternating current generator is connected to the
 rectifier section via a filtering inductor choke assembly that dampens the
 effects of power fluctuation on the output to the load. The commercial
 power flow bypasses the rectifier and inverter section. The rectifier and
 inverter operate in an energized standby mode with no load being supported
 by this section. Upon commercial power loss to the system, the rectifier
 is supported by the flywheel source providing direct current power to the
 inverter until it is replaced with direct current power from the emergency
 generator to support the inverter. Upon command from the system
 controller, the system internal inverter will synchronize the alternating
 current power from its output to the alternate source of the emergency
 generator and transfer the load from the inverter to the emergency
 generator. The emergency generator then supplies electrical power to the
 load until commercial power is restored and then re-transfers to
 commercial power via the filtering inductor assembly. The flywheel section
 must now be returned to normal speed via the alternating current drive
 motor and re-synchronized to the filtering inductor power to get ready for
 the next outage.
 U.S. Pat. No. 4,707,774 discloses a high speed flywheel supported by a
 source of power provided by an inverter that is unsynchronized to the
 alternating current input source to support a direct current chopper
 circuit. The direct current chopper maintains a regulated voltage level of
 direct current to support the inverter circuit. The inverter circuit
 supplies the load with regulated and frequency controlled alternating
 current. Outage protection is supplied as long as the flywheel can provide
 electrical power to support the chopper or an alternating current source
 can restored to the input of the system.
 SUMMARY OF THE INVENTION
 The present invention provides a simple and effective solution to protect
 critical electric equipment and loads during momentary electrical power
 outages without the use and disadvantages of batteries. The incorporation
 of a flywheel and the advancements in technologies allow operation of the
 electrical equipment supported by this system without the disadvantages of
 batteries, such as their extremely short life, their propensity to leak,
 corrode or otherwise deteriorate, and the significant cost associated with
 replacing worn batteries.
 In reference to the prior art, this novel system provides alternating
 current voltage regulation to critical electrical equipment. In one
 embodiment, this novel system provides alternating current voltage
 regulation to non-critical as well as critical electrical equipment. It is
 a simple approach to solving momentary commercial alternating current
 power outages and the return-to-normal operation is enhanced by
 alternating current power factor correcting that augments the reliability
 and efficiency of the electrical equipment supported.
 In its simplest form, the invention is an emergency supplemental power
 supply for outage protection of critical electric loads powered from a
 commercial power grid, including a variable speed drive receiving power
 from the commercial grid, an asynchronous motor powered from the variable
 speed drive for turning a fly-wheel attached thereto to build and maintain
 a level of expendable kinetic energy in the fly-wheel, a coupling of the
 fly-wheel to a synchronous alternating current generator, for driving the
 generator in a no-load, standby condition slightly above the frequency of
 the commercial power on the grid and in a ready condition for input to the
 critical equipment load, a computer processor, in the form of a
 programmable logic controller (PLC) interconnected the variable speed
 drive, the synchronous alternating current generator, and a normally-open
 interrupt contactor for maintaining the supplemental power ready for
 immediate use upon interruption of the commercial electric power and to
 allow the kinetic energy in the rotating fly-wheel to drive the
 synchronous alternating current generator, without further input power
 from the variable speed drive or the synchronous motor, and produce a
 regulated alternating current voltage at a controlled frequency from the
 synchronous alternating current generator to the load. The spinning
 fly-wheel spins down while passing its mechanical kinetic energy into the
 generator to be converted to alternating electrical current for passing to
 the critical load. Even though the fly-wheel and, hence, the synchronous
 alternating current generator, are spinning down, the frequency and the
 voltage are rigidly controlled at specified numbers until the spinning
 gets so slow that the entire unit drops out of the circuit.
 When this embodiment is incorporated with a variable speed drive and motor
 generator, a rotary un-interruptible power supply is created. The
 above-described embodiment may also be coupled with a fossil fuel engine
 to provide unlimited critical load protection.
 Accordingly, the main object of this invention is a supplemental power
 source that eliminates the use of conventional batteries in outage
 protection. The combination of the flywheel and an alternating current
 generator produces high current demands for short periods of time,
 allowing either sufficient time for the return of normal commercial
 alternating current power, or for transfer of the input source from
 commercial power to the emergency generator set, via an automatic transfer
 switch, to provide outage protection for a period that provides a logical
 and safe shutdown of equipment.
 Other objects of the invention include reduced alternating current power
 consumption during ride-through-module startup that is accomplished by
 using an integrated variable speed drive (VSD) to support an asynchronous
 support motor; an integrated variable speed drive that is provided as a
 self-sufficient part of the system and sized for the alternating current
 asynchronous motor which is to be supported; a variable speed drive used
 to start and maintain operational speed of the flywheel and generator used
 to provide outage protection power; a system where the operational speed
 in the maximum ride-through-mode is faster than 60 Hertz and the generator
 will be inhibited from connection to commercial power. This invention is
 designed such that the variable speed drive that operates the support
 motor will remain on until there is a power outage. Still further, the
 flywheel, bearings and coupling device of this invention can be sized for
 the power required to support the specific load for which the invention is
 designed to protect and are off-the-shelf items that can be readily
 obtained without special order. The flywheel of this invention is designed
 for continuous operation without failure or bursting. The amount of
 protection time from outages is determined by the flywheel kinetic energy
 based on mass and operational speed. The invention's versatility is
 provided by the ability to support either the internal variable speed
 drive or other existing variable speed drives that are already in place
 within a facility. It can also support critical alternating current
 electric loads and frequency tolerant alternating current resistive loads.
 The invention has the ability to transfer load when programmed in
 conjunction with an emergency power generator to route the load through
 the integrated variable speed drive thus replacing the power provided by
 the kinetic energy of the flywheel and continue operation without
 interruption to the load.
 In another embodiment of this invention, the system has the ability to
 incorporate an internal load-rated variable speed drive that will support
 a motor generator. The motor generator can be built into the package,
 provided separately or be already existing. This capability allows for
 upgrading of existing equipment to provide outage protection. The
 invention can also be used to support pump or fan motors, electrical
 process motors and other components.
 In still another embodiment of this invention, the system has enhanced
 capabilities to support an integrated motor generator that is coupled via
 a overriding clutch to a prime mover such as a reciprocating engine. This
 embodiment allows for continuous outage protection without affecting the
 supported load and allows for the flywheel portion to return to normal
 operation while the load is being supported externally. Conventional
 flywheel-based systems incorporate many more components in comparison to
 the invention presented. This invention has decreased parts count (less
 parts) and the non-reproduction of electrical power offers an economical,
 more efficient and simple approach to solving momentary outage problems.
 In even another embodiment of this invention, an alternating current
 ride-through module comprises an alternating current asynchronous motor,
 an alternating current generator, a flywheel, an integrated coupling
 device, a variable speed drive, a system monitoring/controller and
 associated switching devices. To fully encompass all power quality
 deviations, a motor generator, overriding clutch and engine are also
 required. This invention provides a total approach to supporting loads
 that are either frequency tolerant, variable speed drive driven and
 supported by the duration of the kinetic energy provided by the flywheel,
 or enhanced with the addition of an engine with overriding clutch.
 The use of the invention will provide outage protection from a renewable
 power source without the use of conventional batteries. This eliminates
 the routine of capacity check for batteries and replacement problems that
 occur with disposal of hazardous material. The invention also allows for
 an environment that does not have the critical requirements of batteries.
 Operation of the equipment in normal earth ambience without any sign of
 deviation in power capacity or capability, thus eliminating required air
 conditioning and refrigeration hazards. The use of alternating current
 rather than direct current prevents safety risks associated with high
 voltage direct current. This also eases the installation process of the
 equipment due to direct current hazards.
 These and other objects of the invention will become more clear when one
 reads the following specification, taken together with the drawings that
 are attached hereto. The scope of protection sought by the inventors may
 be gleaned from a fair reading of the Claims that conclude this
 specification.

DESCRIPTION OF THE PREFERRED EMBODIMENT
 Turning now to the drawings, where elements are identified by numerals and
 like elements are identified by like numerals throughout the thirteen
 figures, FIG. 1 shows the basic embodiment of the invention 1 of an
 emergency supplemental power supply for outage protection of critical
 electrical equipment, generally termed a "load" 3, such as molding
 machinery, metal lathes, computer-controlled metal forming equipment,
 computers and the like, powered from a commercial power grid 5 such as 60
 Hertz and 120/240 or 240/480 volts, and shows a variable speed drive 7
 with input from commercial power grid 5 in parallel with the critical
 electric equipment load 3 through a first grid input interrupt contactor
 9, interposed power grid 5 and load 3, and a second interrupt contactor 11
 that remains closed during commercial power input to load 3 and that opens
 automatically during sags, spikes, or other interruption of the commercial
 power.
 Variable speed drive 7 contains a rectifier device, that transforms
 alternating (cyclic) commercial current to direct current, and an
 inverter, that transforms the direct current back into alternating
 current. Controls are provided on variable speed drive 7 to insure the
 output alternating current is of a certain frequency. An example of a
 variable speed drive useful in this invention is a 10 horsepower rated,
 480 Volt AC, 3-phase, 60 Hertz drive manufactured by Danfoss, Inc. of
 Rockford, Ill. It is necessary to size each variable speed drive for the
 specific use intended.
 Interrupt contactors 9 and 11 are protective devices that will open with a
 few micro-seconds following a commercial power outage. They are used in
 this invention to isolate load 3 from commercial power grid 5 immediately
 following the outage and to isolate variable speed drive 7 from load 3
 thus allowing the entrance of invention 1. An example of an interrupt
 contactor useful herein is a 100 horsepower rated, 480 Volt AC, 3-phase,
 60 Hertz contactor made by Sprecher & Shuh, of Houston, Tex. Sizing of
 interrupt contactors 9 and 11 is absolutely necessary to insure successful
 operation of the invention.
 An asynchronous motor 13 is provided, connected to variable speed drive 7,
 and powered therefrom having an output shaft (not shown) connected through
 a first coupling 15a to a fly-wheel 17 for turning said fly-wheel 17 from
 power received from commercial power grid 5, to build and maintain a level
 of expendable kinetic energy in said rotating fly-wheel 17. An example of
 an asynchronous motor useful herein is a 10 horsepower rated, 480 Volt AC,
 3-phase, 60 Hertz motor made by Marathon, Inc. of Wausau, Wis. There are a
 number of such motors on the market and choosing the proper one for the
 specific size of invention (in relation to load 3) is vitally necessary.
 Coupling 15a may be a rubber-based coupling. An example of coupling 15a
 useful herein is Para-Flex Px-120 made by Dodge Coupling, of Detroit,
 Mich.
 Fly-wheel 17 may be small, large, or of a variety of designs and be thin,
 thick and made from a variety of materials. It will turn in the
 neighborhood of 2,400 rpm and, thus, must be made from high-grade steel or
 the like in order to reduce the chances of a possible explosion due to
 centrifugal force developed during rotation. The design of fly-wheel 17
 will depend upon the size of critical electrical equipment load 3 and
 other factors such as the size and power requirements of the various
 pieces of equipment that make up this invention. An example of fly-wheel
 17 useful herein is a 650 pound fly-wheel made by McKee's Rocks Forging,
 Inc. of McKees Rocks, Pa.
 Fly-wheel 17 is connected through a coupling 15b to a synchronous
 alternating current generator 19 so that flywheel 17 can drive generator
 19 in a no-load, standby condition. Coupling 15b may take the form of many
 such clutch-type couplings available on the market. Coupling 15b must be
 sized to handle the load from fly-wheel 17. Research has concluded that
 only a small amount of electrical power, such as 5 amps, need be drawn
 from the power grid in order to support the rotation of fly-wheel 17
 through variable speed drive 7. An example of a synchronous alternating
 current generator for use herein is a K-Mag 14 Series Generator made by
 Kato Engineering. The size and capability of generator 19 depends upon the
 size of load 3 and other factors. Because generator 19 does not feed a
 load when commercial power is applied to load 3, it requires a minimum
 self-excited electrical supply to establish a no-load, synchronized,
 standby condition.
 A computer processor or programmable logic controller 21 is interconnected
 variable speed drive 7 and synchronous alternating current generator 19
 for controlling the operation of invention 1. In controlling invention 1,
 processor/controller 21 calls for asynchronous motor 13 to be powered,
 called "ramping up", to turn fly-wheel 17 at a speed that causes
 alternating current generator 19 to produce a 3-phase, alternating current
 with commercial power, at the voltage required by load 3, and at a
 frequency slightly above that of the commercial power grid, such as about
 75 Hertz. Variable speed drive 7 also maintains fly-wheel 17 at the
 required speed so that the frequency of alternating current output from
 generator 19 in a ready condition for input to critical equipment load 3.
 An example of a computer processor useful herein is a Micro 3 PLC made by
 IDEC. The characteristics desired in a useful computer processor must be
 matched to the size of load 3 and other factors.
 A third interrupt contactor 25 is provided, interposed generator 19 and
 load 3, and controlled by computer/processor 21. When commercial power or
 whatever main source of power being used suffers an outage, both first
 interrupt contactor 9 and second interrupt contactor 11 react almost
 immediately and open to isolate load 3 from the commercial power line and
 variable speed drive 7 from generator 19. Computer processor 21
 simultaneously (in a few micro-seconds) closes interrupt contactor 25 so
 that power interruption is nothing more than a "blip" on the graph of
 power supplied to load 3. An example of third interrupt contactor 25
 useful herein is 100 horsepower rated, 480 Volt AC, 3 phase, 60 Hertz made
 by Sprecher & Shuh, of Houston, Tex. Interrupt contactor 25 should be
 sized to handle the expected load from generator 19.
 The kinefic energy in rotating fly-wheel 17 is then coupled through
 coupling 15b to drive synchronous alternating current generator 19 and
 produce a regulated alternating current voltage with decaying frequency
 from generator 19 to load 3. This is accomplished without further input
 power from variable speed drive 7 or from asynchronous motor 13 because
 the commercial power that drives them is now interrupted. The reason the
 frequency is decaying is that fly-wheel 17 loses drive power from motor
 13, as soon as commercial power is interrupted, and begins to spin down,
 and delivers, from generator 19, a packet of electrical power to allow the
 equipment in load 3 to shut down. This embodiment is useful when
 connecting the invention through a variable speed drive (not shown)
 provided by the customer or already in the commercial power loop.
 FIG. 2 is a graph showing the frequency and voltage to load 3 from the
 embodiment of the invention shown in FIG. 1 after implementation of the
 outage protection of this invention following a commercial power outage.
 The abscissa of FIG. 2 is time in seconds and begins at -2 wherein the
 length from -2 to 0 shows the input of commercial power from grid 5 and
 the length from 0 to 22 is the number of seconds immediately following the
 onset of emergency supplemental power from invention 1. FIG. 2 shows, in
 solid line, the jump from 60 Hertz to 75 Hertz that is accomplished by
 running fly-wheel 17 at a speed sufficient to turn synchronous alternating
 current generator 19 at a speed to obtain this amount of frequency. Note
 that voltage (the dotted line) in FIG. 2 does not waiver except for the
 small blip at 0 seconds which is caused by the rapid opening of first and
 second interrupt contactors 9 and 11 and the closing of interrupt
 contactor 25.
 As fly-wheel 17 turns synchronous alternating current generator 19, it
 gives up its kinetic energy to generator 19 and, in the process, begins to
 slow down. As it slows down, the frequency drops off, as shown in FIG. 2,
 and, when the frequency reaches about 40 Hertz (in a 60 Hertz powered
 load), the system collapses into a shut down mode. Note that this collapse
 is reached only after about 20 seconds thus providing critical load 3 with
 sufficient time to engage and complete its own programmed shutdown
 procedures.
 Note also that during this 20-second supplemental power process, the
 voltage, measured on the right ordinate, remains at an unchangeable 220
 volts A.C. Thus, in this embodiment, following a commercial power outage,
 the frequency varies while the voltage applied to load 3 remains
 substantially unchanged. The term "substantially" is used to take into
 account the slight "blip" at the onset of the commercial power outage.
 As previously described, the importance of this invention is to provide
 instantaneous supplemental power, following the failure of commercial
 power, for a period in which critical electrical equipment can pass into a
 shut-down mode to protect the equipment and save their work pieces on
 which they are operating at the moment of commercial power interruption.
 It has been estimated that this period may vary from 8 to about 20 seconds
 for most electric equipment that requires most of the attention. However,
 depending upon the load on the grid and the equipment peculiarities, this
 period may require extension to beyond 20 seconds. Accordingly, this
 invention is easily modifiable to extend such period, mainly by increasing
 the amount of kinetic energy stored by fly-wheel 17. In other cases, the
 period may be increased by immediately cutting off other, non-essential
 electric loads such as lights, heaters, and the like.
 In another embodiment of this invention, as shown in FIG. 3, emergency
 supplemental power supply 1 may include a second variable speed drive 27
 interposed interrupt contactor 25 and load 3. Second variable speed drive
 27 rectifies the incoming alternating current, from synchronous
 alternating current generator 19, to direct current and then inverts the
 direct current to a frequency-specific alternating current for powering
 the critical electric equipment load.
 FIG. 4 shows the effect of interposing second variable speed drive 27
 between generator 19 and load 3. Variable speed drive 27 forms the
 frequency of the alternating current of the supplemental power at 60 Hertz
 so that there is no initial increase of frequency or a gradual tapering
 off thereof as shown in FIG. 1. By this means, more accuracy is placed on
 the alternating current passing into load 3 and the specific alternating
 current remains somewhat longer at the appropriate frequency, such as 60
 Hertz, before decaying due to the slowing of the spinning fly-wheel 17. In
 this embodiment second variable speed drive 27 obtains commercial power
 from commercial power grid 5 during normal operations of commercial power.
 This embodiment provides more accurate supplemental power than does the
 embodiment shown in FIG. 1.
 In a still further embodiment of emergency supplemental power supply 1 for
 outage protection of critical electric equipment load 3, powered from
 commercial power grid 5, is shown in FIG. 5. Here, the feed lines from
 grid 5 to second variable speed drive 27 and from synchronous generator 19
 (through second interrupt contactor 25) to second variable speed drive 27
 are totally separated. This embodiment is significant when dealing with
 momentary drops in frequency and/or current from commercial power grid 5.
 These are called "sags" and may cause certain electric equipment to drop
 off line and become damaged due to freeze-up of materials being operated
 upon by the equipment. The separate inputs from commercial power grid 5
 and synchronous generator 19 allow fly-wheel 17 to provide power to
 synchronous generator 19 and provide synchronized supplemental power
 through interrupt contactor 25 during these momentary sags. The electrical
 characteristics of this embodiment are shown in FIG. 4 and are the same as
 shown in the embodiment shown in FIG. 3. However, both the alternating
 power coming from variable speed drive 27, in the embodiments shown in
 FIGS. 3 and 5, is not "pure" alternating power. Alternating current
 manufactured by a variable speed drive contains areas of non-sinusoidal
 waves caused by the characteristics of the transistors and other elements
 inside the drive and is statically manufactured, non-sinusoidal as shown
 in FIG. 7.
 In a still further embodiment of invention 1, shown in FIG. 6, a second
 variable speed drive 27 is provided as before, interposed commercial power
 grid 5 and critical electric equipment load 3 and a second asynchronous
 motor 29, coupled to a second synchronous generator 31, in combination,
 known as a "motor-generator set", is interposed second variable speed
 drive 27 and critical electric equipment load 3. Computer processor
 control means 21 is interconnected both first and second variable speed
 drives 7 and 27, synchronous alternating current generator 19, second
 asynchronous motor/second synchronous generator combination 29/31, and
 interrupt contactor 25, this time for not only maintaining the frequency
 of alternating current and voltage output from synchronous alternating
 current generator 19 in a ready condition for input to said second
 variable speed drive 27. Second asynchronous motor/second synchronous
 generator combination 29/31 provides such improved power. This improved
 alternating power, shown in FIG. 8, generally known as "clean conditioned
 power with total isolation from utility power", can handle
 computer-operated equipment and other critical equipment that requires
 more accuracy in the alternating current passing into load 3.
 In a still further embodiment of invention 1, shown in FIG. 9, second
 variable speed drive 27 is provided as before, interposed commercial power
 grid 5 and critical electric equipment load 3 and second asynchronous
 motor 29, coupled to a second synchronous generator 31, the
 "motor-generator set", is interposed second variable speed drive 27 and
 critical electric equipment load 3. Computer processor control means 21 is
 interconnected both first and second variable speed drives 7 and 27,
 synchronous alternating current generator 19, second asynchronous
 motor/second synchronous generator combination 29/31, and interrupt
 contactor 25. In addition, the feed lines from commercial power grid 5 to
 second variable speed drive 27 and from synchronous generator 19 (through
 interrupt contactor 25) to second variable speed drive 27 are totally
 separated and independent of each other. This embodiment not only
 maintains the frequency of alternating current and voltage output from
 synchronous alternating current generator 19 in a ready condition for
 input to said second variable speed drive, but it provides a more pure
 form of sinusoidal wave alternating power, such as is shown in FIG. 8. In
 addition, the dual inputs provide less strain on variable speed drive 27
 than a single input feed line.
 In another embodiment of the invention, shown in FIG. 10, second
 asynchronous motor 29 is again coupled to second synchronous generator 31,
 in combination, and interposed second variable speed drive 27 and critical
 electric equipment load 3. A prime mover 33, such as a gasolene-powered or
 diesel-powered internal combustion engine, is provided, including a
 coupling 37 for coupling prime mover 33 to second asynchronous
 motor/second synchronous generator combination 29/31. An example of a
 prime mover useful herein is a 50 HP Diesel engine made by Perkins Engines
 from the United Kingdom. The exact size of such a prime mover is
 determined from a number of variables, such as the size of load 3, etc.
 Under operation of computer processor 21, contactor 25 is caused to close
 upon the interruption of incoming grid power 5 to load 3, to allow the
 kinetic energy in rotating fly-wheel 17 to drive first synchronous
 alternating current generator 19 and produce an alternating current
 voltage and frequency from synchronous alternating current generator 19 to
 second variable speed drive 27, for supplementing the sag or outage from
 the commercial power grid to the load, for a period sufficient to allow
 prime mover 33 to start and come up to a speed necessary to couple through
 coupling 37 to second asynchronous motor 29 and provide lasting
 supplemental power to the critical load as shown in FIG. 11.
 A modification to the embodiment of the invention shown in FIG. 10 is shown
 in FIG. 12 wherein the input feed lines from grid 5 to second variable
 speed drive 27 and from synchronous generator 19 (through interrupt
 contactor 25) to second variable speed drive 27 are totally separated.
 This embodiment provides less tension on variable speed drive 27 as
 previously described.
 A final embodiment of this invention is shown in FIG. 13 and shows prime
 mover 33 coupled to synchronous alternating current generator 19 through
 coupling 37, separate input feed lines into second variable speed drive
 27, to deal with sags and reduce the shock load to drive 27, and
 motor/generator set 29/31 interposed second variable speed drive 27 and
 load 3 to condition the supplemental alternating power to load 3. In this
 embodiment, prime mover is coupled to synchronous alternating current
 generator 19 and sized to produce more power than is needed by load 3. An
 automatic transfer switch 39 is provided having one incoming leg attached
 to commercial power grid 5, another incoming leg attached to the
 supplemental power line passing from synchronous alternating current
 generator 19 to interrupt contactor 25 and a third leg leading to a second
 load 41. Switch 39 is biased toward receiving commercial power from grid 5
 and will provide this commercial power to load 41 which is preferably made
 up of non-critical loads such as resistive loads like heaters and lights.
 Upon an outage of commercial power in grid 5, switch 39 immediately
 switches to invention 1 and receives power from alternating current
 generator 19 while critical load 3 receives the same power, however it is
 conditioned through motor/generator combination 29/31 to provide clean
 condition power which is totally isolated from utility or commercial
 power. Fly-wheel 17 provides the initial power, so that there is no
 interruption to either load 3 or load 41, while prime mover 33 is started
 and brought up to speed to begin to power synchronous alternating current
 generator 19 to provide lasting power to both load 3 and load 41.
 While the invention has been described with reference to a particular
 embodiment thereof, those skilled in the art will be able to make various
 modifications to the described embodiment of the invention without
 departing from the true spirit and scope thereof. It is intended that all
 combinations of elements and steps which perform substantially the same
 function in substantially the same way to achieve substantially the same
 results are within the scope of this invention.