FIELD OF INVENTION;
The present invention relates to power protection system with built-in Time delay switch for electrical and electronics equipments, and more particularly to adjustable time delayed and good quality power controller apparatus for such equipments.
PRIOR ART:
Time delay relays are known which use a variety of components including solid-state, electromechanical, thermal, and pneumatic devices to establish a delay period.
IN 187881 is An Electronic Device for Time Delay and Low/High Voltage Protection.
US Patent No 4204128 discloses an Adjustable Time Delay Relay which is related to electrical apparatus and more particularly to TDR employing solid state component, transistor and diode to provide a delay period.
US Patent No 4480194 is directed to a Circuit for Supplying a Control Contact with Power and Application Thereof for the Control of a Rest Time Delay of a Relay. This relay works only for auxiliary supply.
US Patent No 4498019 relates to a Switching Circuit with a Time Delay Device. This includes a pulse generator and counter using logic gates to determine the time delay.
US Patent No 5296786 is a Time Delay Relay Arrangement. This system is a voltage switching arrangement for an electrical power control system including a plurality of switches for supplying and dissupplying voltage from the input to a power transfer network, which provides power for a load.
US Patent No 4331996 is a Time delayed Under Voltage Relay. The system is an under voltage relay device for a circuit breaker system with a time delay feature, output of which is rectified and provided to a capacitive element (comprising single capacitor or a combination of capacitors), which among other things filter the signal.
US Patent No 4412267 is a Time delay current Sensing Circuit Breaker Relay. This invention pertains generally to relays which also perform circuit protective functions, such as those used as battery to electrical system contactors in aircraft application and in particular to circuit breaker relays which trip open due to an over current condition after a predetermined period of time delay.
US Patent No 5909064 is a Time delay Relay Circuit. This discloses a time delay relay circuit for battery powered devices and more particularly to a relay having minimal battery drain when not in use.
US Patent No 4516183 is an Over Current Relay. This system includes an input transformer, a rectifying circuit and a level detecting circuit.
US Patent No 4719364 is a Multiple Time Delay Power Controller Apparatus. This is related to the field of time delay power controller apparatus for electrical and electronic equipment.
US Patent No 5051607 is a Switch Time Delay Apparatus. This is a time delay relay configured to connect in parallel with a common single pole switch.
AU530044 is a Time Delay and a pneumatic device.
EP220504 is a Multiple Time Delay Power Controller Apparatus having analog circuits using transformer. Timer, discreet component and 1C have been utilized for multiple components.
CA1026830, a Solid State Time Delay Switch, US Patent No 4371791, a Time Delay Switch and 4630021, a Low Cost Time Delay Relay Assembly are thermostatic switch.
CA 1042071 is a Time Delay Switching Circuit having two operating modes. When the switching circuit is set in the first operating mode, the generated signal from the timing means causes the holding means to actuate the Triac and effect application of the AC power across the load at the end of the time interval. When the switching circuit is set in the second operating mode, the generated signal from the timing means causes the holding means to de-actuate the Triac and effect the disconnection of the AC power source from across the load at the end of the time interval.
The various type of time delay relays disclosed in the prior art are either specifics to a particular type of application or consists of analog circuitry having various components like solid state components and resistance-capacitance network, and logical ICs for providing the necessary time delay relay operation. Such systems are complicated in construction and production due to large number of components and provide time delay which varies due to the variation of various components over a period of time. None of them are having the provision for the adjustment of the time delay operation or voltage and frequency window.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide power Protection System with Built-in Time Delay Switch which provides the adjustment for time delay operation or voltage and frequency window.
Another object of the present invention is to provide power protection system with Built-in Time Delay switch which provides complete power protection to equipment with required time delay.
Further object of the present invention is to provide power protection system with Built-in Time Delay switch which overcomes the drawbacks of Time Delay Relays known in the prior art.
Further object of the present invention is to provide power protection system with Built-in Time Delay switch which provides option for setting of time delay, AC voltage window, and frequency window and user friendly display by providing a user interface with this apparatus.
Still another object of the present invention is to provide power protection system with Built-in Time Delay switch to operate the relay or static switch at a zero voltage of the AC power by sensing the frequency and phase.
Yet another object of the present invention is to provide power protection system with Built-in Time Delay switch to track the line voltage waveform and to identify the primary power source (grid/generator supply) and secondary power source (compatible inverter power supply).
In the other embodiment the objective of the present invention is to provide the user interface through key pads/touch panel.
In the other embodiment the objective of the present invention is to provide the display indications for various parameters and conditions on LCD.
In the other embodiment there may be provisions for multiple time delayed outputs and measurement of power consumption of the equipment.
Yet another further object of the present invention is to provide power protection system with Built-in Time Delay switch to serve the purpose of electronic M.C.B in case of overload and sort-circuit conditions with automatic restart facility.
Still another object of the present invention is to provide power protection system with Built-in Time Delay switch to serve the purpose of power controller devices with variable time delay that can be connected at the output of power supply systems to run the multiple equipments/appliances/loads with different time delay.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus of a Power Protection System with Built-in Time Delay Switch. Whenever there is grid supply failure or voltage fluctuation or frequency variation from specified limits, the power protection system disconnects the equipments from the grid supply. When grid supply resumes or voltage/frequency become in the specified limit then power protection system reconnects the equipment to grid supply with a specified time delay from few seconds to few minutes. It has a flash micro-controller to monitor the quality of grid power and control the operation of the connected equipments. All the voltage and frequency limits are programmable and factory settable according to application requirements.
STATEMENT OF INVENTION
According to this invention there is provided a power protection system with built-in time delay switch comprising of a power supply section to activate a controller connected to power supply and signal conditioning for AC voltage and frequency sensing, Relay/static switch, spike and surge protection, current sensing and reference setting for adjustable time delay, grid voltage and frequency section as shown in fig. 1.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
FIG. 1 shows a block diagram of power protection system with built-in adjustable time delay relay / static switch operation
FIG. 2 shows a circuit diagram for power supply required for controller, relay or static switch (SCR/TRAIC) drive and line voltage/frequency sense.
FIG. 3 shows a circuit diagram of controller for line voltage/frequency sensing, current sensing, relay/static switch control and display;
FIG. 4A shows flow chart PPS operation; FIG. 4B shows the continuation of fig 4A; FIG. 4C shows the continuation of fig 4A;
FIG. 5 shows block diagram for multiple loads running through multiple power protection systems (PPS) with different time delay;
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
Reference may be made to fig. 1 indicating the overall view of the system. The AC power supplied to equipment is either from primary power source (grid/generator power/bypass or mains mode of inverter) or from secondary power source (backup mode of inverter - means power supplied after DC to AC conversion operation of inverter). The switch SW can be set in 'ON' condition if there is no standby power source (inverter). Power supply section provides the DC power to activate the controller (6), relay/static switch (5) and other signal conditioning circuit etc. Controller supplies the good quality power to equipment/load. Controller also detects the condition of over/under voltage, over/under frequency and over current. Further, it cut offs the equipment (8) in case of bad power quality or overload/short circuit by using relay/static switch (5).
The controller tracks the line waveform each time after failure or restore or interruption of the grid/generator power supply. The controller detects the power supplied from compatible inverter system which is running in backup mode by analyzing the waveform using a special software protocol based on the output waveform frequency measurement. Controller tracks the frequency of line voltage waveform and records the
time periods (To, Ti, T2 Tn) for different frequencies (Fo, Fi, F2...Fn) for a
specified time. Controller then maps the different frequencies with time
periods (Fo:T0, Fi:Ti, F2)T2 Fn:Tn). If mappings match with the
defined mapping corresponding to secondary power source then controller takes the decision that the power is being supplied by a compatible inverter system running in backup mode. The controller generates the special indication in case the power is supplied to equipment by inverter running in backup mode. Connected equipment/load can be run for a predefined time from inverter power backup supply by defining time during programming the controller.
This power protection apparatus serves the purpose of electronic M.C.B in case of overload and short-circuit with automatic restart facility after a specified time during the programming of the controller. Controller disconnects the equipment after few milliseconds to few minutes depending on the overload percentage.
Fig 2 is a circuit diagram for power supply required for controller, relay or static switch (SCR/TRAIC) drive and line voltage/frequency sense. This system operates with a transformer-less supply. The transformer¬less capacitive power supply has been designed using full bridge rectifier with transient protection and EMI filter. There are two power supplies: one to operate the transfer relay or static switch and second to operate the micro-controller, display and other signal conditioning circuitry. A resistor divider network with low pass filter reduces the line signal level which is fed to built-in A/D converter of the micro-controller to monitor the line voltage and frequency measurement.
Fig 3 is a circuit diagram of controller for line voltage/frequency sensing, current sensing, relay/ static switch control and display. Micro-controller monitors the quality of grid power and controls the operation of the connected equipments. Micro-controller cuts off the equipments from the bad quality power within a short time due to its fast detection and response timings. Micro-controller senses the reference voltage of an adjustable potentiometer. Micro-controller sets internally time delay for relay switch operation corresponding to this reference voltage. Micro¬controller senses the jumper positions (Jl & J2) for input AC voltage and frequency window selection. The micro-controller senses the input AC voltage and frequency by sampling the corresponding AC voltage signal through built-in A/D converter. Micro-controller calculates the voltage level through a software algorithm. Micro-controller also compares the digital value of sampled AC signal with internal reference to detect the frequency and phase of the AC input supply. Whenever there is AC power supply failure or voltage fluctuation or frequency variation out of specified limits, this power protection system disconnects the equipments from the AC power supply. When the AC power supply resumes or voltage/frequency in the specified limit then power
conditioner reconnects the equipment to AC power supply within a specified time delay, ranging from few milliseconds to few minutes.
All the voltage/frequency and time limits are programmable and factory/ user settable according to requirements regarding applicability.
Micro-controller operates the relay or static switch to connect the equipment to good quality AC power supply with a factory/user settable time delay. Micro-controller operates the relay or static switch near to zero voltage of the AC power supply by sensing the frequency and phase of the AC power supply.
Controller also provides the following indications through display device:
1. Availability of AC power and supplying to equipment
2. Wait or time delay operation during time delay mode after power
resumes or under/over voltage cutoff
3. Under or over voltage or frequency out or bad power quality.
4. Supply of power to equipment either by primary source (Grid or
Generator or bypass/mains mode of Inverter) or by secondary
standby source (backup power supply from Inverter).
Fig 4A, 4B, 4C is the flow chart outlining the software program procedures for the operation of the power protection apparatus with built-in time delay, according to the present invention. The Controller monitors the various parameters by reading through built-in A/D converter according to software procedures and takes the logical decision based on various conditions. The controller controls the operations of the said power protection system and provides the necessary indications to user as per the condition.
FIG. 5 is block diagram for multiple loads running through multiple power protection systems (PPS) with different time delay. PPS serves the purpose of power controller devices with variable time delay which are connected at the output of power supply systems (like inverter, UPS, generator etc) to run the multiple equipments/appliances/loads with different time delay. Thus, power supply system handles the surge current of multiple equipments/appliances/loads easily by setting different time delay.
It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM
1. A power protection system with built-in time delay switch
comprising of a power supply section to activate a controller
connected to power supply and signal conditioning for AC
voltage and frequency sensing, Relay/static switch, spike and
surge protection, current sensing and reference setting for
adjustable time delay, grid voltage and frequency section as
shown in fig. 1.
2. A power protection system as claimed in claim 1 wherein the
power supply section is in connection with the relay/static
switch and power supply and signal conditioning for AC voltage
and frequency sensing.
3. A power protection system as claimed in any of the preceding
claims wherein the controller is attached to a display so as to
provide necessary indications therein.
4. A power protection system as claimed in any of the preceding
claims wherein the power supply section comprises of primary
power source (grid/generator power/bypass or mains mode of
inverter) or secondary power source (backup mode power
supply of inverter-means power supplied after DC to AC
conversion operation of inverter).
5. A power protection system as claimed in any of the preceding
claims wherein the system operates with a transformer-less
supply having full bridge rectifier with transient protection and
EMI filter.
6. A power protection system as claimed in any of the preceding
claims wherein the controller is programmed with required
software so as to monitor the various parameters by reading
through built-in A/D converter.
7. A power protection system as claimed in any of the preceding
claims wherein the plurality of systems can be assembled as
shown in fig .5 for multiple loads running there through with
different time delay.
8. A power protection system with built-in time delay switch
substantially as herein described with reference to the
accompanying drawings.