|Title of Invention||
A SAFER POWER SUPPLY SYSTEM FOR REDUCING ELECTRIC SHOCK RISKS
|Abstract||A safer power supply for reducing electric shock risks comprising an electric apparatus operable on a.c. and d.c., a full wave rectifier built into the said apparatus, and an a.c. source provided with an earthed neutral,the input of the said rectifier being connected to the said source and the d.c. output of the said rectifier being conneected to the input of the said apparatus.(Fig 1)|
This invention relates to a safer power supply system^for reducing electric shock risks.
Normally, risk of electric shock is more pronounced in the use of domestic & industrial portable electric appliances and for this reason such appliances are designed for single phase AC operation, not only in India but also abroad. In certain countries 110AC voltage is used for power supply and the equipment to be used therewith is designed for 110AC voltage only. Similarly, in certain other countries, like India, 220 AC voltage is used for power supply and the equipment to be used therewith is designed for 220 AC voltage only.
Motorised portable power operated equipments such as Mixies, Wet grinders, Portable Drilling Machines, Portable Grinders, Butter Churnners and the like are desinged to be operated by AC/DC Motors for the sake of compactness and better power torque and all these types of equipment operate on single phase AC.
Non Motorised Equipment such as Electric Irons, Toasters, Rice Cookers, Immersion Heaters, Room Heaters, Storage Water Heaters, Electric Pressure Cookers, Table Lamps and the like also operate on single phase AC only.
Reports and Surveys on electric Shock Accident reveal that most of such accidents are caused by portable electric equipment by reason of wear and tear of the connecting leads, Moisture entering the equipment, insulation failure due to rough handling and heat damaging the connecting leads and so on.
The main object of this invention is, therefore, to propose a safer power supply system for reducing electric shock accidents caused in the manner referred to above.
This invention will now be described with reference to the accompanying drawings wherein
Figure 1 Illustrates the resistive load powered by a 200v full wave bridge rectifier. Points A,B,C,D, and E refers various points on the resistive load at which when a person while electrically connected to earth, touches, will get 100 volt across his body.
And when his body resistance is 10 k ohms, 10mA Shock current will flow through his body to earth i.e. the maximum shock current level is reduced to 50% when the load is operated by Full Wave Rectified D.C.
And Figure 2 Illustrates a Table Lamp
When equipment of the kind referred to above is operated by Full Wave Rectified Current, the shock voltage (Compared to earth) will be 110 A.C/D.C in the case of 220 volt A.C power supply.
In the case of 110 Volt A.C power supply, the A.C or D.C voltage is 55 volts and thus the shock current voltage is reduced by 50%.
The power conversion from A.C to D.C is easily done by using silicon diodes which are economical and compact. The Silicon Diode Bridge Circuit for converting A.C to Full Wave D.C can be easily accommodated in portable electric equipment (exemplified by the apparatus mentioned above) and by reason of negligible power loss, does not get over - heated.
The said bridge circuit can also be incorporated in wiring accessories such as Plug Top of such equipment. Thus, the said bridge circuit can be incorporated in the plug top 1 or in the base portion 3 of the Table Lamp.
The other parts of the apparatus (table lamp) illustrates in Figure 2 are the connecting wire 2 (wiring accessory) ; 'ON1 'OFF' switch 4; adjustable stem 5 of the Table Lamp (with wire 2 inside); filament lamp 6 fixed to the holder; and lamp shade 7. Incorporating A the said bridge circuit in plug tops has the further advantage, i.e. the conventional plug tops can be readily replaced by the new plug tops incorporating the said bridge circuits, thus enabling the benefits of this invention to accrue immediately, in regard to conventional apparatus, that is, manufactured, in accordance with this invention.
But it is advisable for the new apparatus manufacture in future, to indlude the Bridge Rectifier within the apparatus itself instead of the plug top. Because when once the plug top or the connecting lead gets damaged, the user may replace it by a different plug top with the conncecting lead, which may not have a built-in Bridge Rectifier and the PURPOSE OF SAFETY IS DEFEATED.
Needless to say, this invention is also applicable to lighting loads involved in construction site lighting, stage lighting, swimming pool lighting, tower lighting, open air lighting, yard lighting, gate lamp lighting, back yard lighting and other loads which can be operated on DC.
Fig 2 also illustrates, respectively, the conventional table lamp wiring and a table lamp wiring diagram with the full wave bridge rectifier connected inside.
The full wave bridge rectifier included immediately after the ON OFF control switch of the table lamp as illustrated reduces shock risk to 50% level.
The description given above illustrates and exemplifies, but does not limit the scope of the invention.
I CLAIM :
1. A safer power supply system for reducing electric shock risks
comprising an electric apparatus operable on a.c. and d.c, a full wave
rectifier built into the said apparatus, and an a.c. source provided with an
earthed neutral, the input of the said rectifier being connected to the said source
and the d.c. output of the said rectifier being connected to the input of the said
2. A safer power supply system as claimed in Claim 1 wherein the said
apparatus comprises a wiring accessory and the said rectifier is built into the
3. A safer power supply system as claimed in Claim 2 wherein a portion
of the said apparatus other than the said accessory has the said rectifier built
4. A wiring accessory for a safer power supply system as claimed in
any one of the Claims 1 to 3 having a full wave rectifier built into it.
5. A safer power supply system as claimed in any one of the preceding
Claims wherein the said rectifier is a full wave semiconductor bridge.
6. A safer power supply system for reducing electric shock risks,
substantially as herein described with reference to, and as illustrated in the
|Indian Patent Application Number||134/MAS/1999|
|PG Journal Number||50/2007|
|Date of Filing||03-Feb-1999|
|Name of Patentee||ARULANANDASAMY JOSEPH STEPHEN|
|Applicant Address||166 DEVELOPED PLOT ESTATE, PERUNGUDI, MADRAS 600 O96,|
|PCT International Classification Number||H02H 1/00|
|PCT International Application Number||N/A|
|PCT International Filing date|