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Inverter.........!

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by koolguy, Aug 31, 2010.

  1. unclejed613

    unclejed613 Well-Known Member

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    i'm doing some design work for a 3rd world country. power infrastructure in these countries is limited. remember that many of these countries have not even had stable governments, let alone the infrastructure required to keep services in working order. whether the infrastructure is government owned or privately owned doesn't really matter, it's difficult to keep things working in a politically unstable environment. infrastructure also takes money to maintain, and many countries don't have the money to properly maintain what infrastructure they do have...
    here in the US it took 30 years or more to get every house on the grid, up until 1968 or so, there were still AC-DC powered appliances being produced, and the Rural Electrification project began in the 1930's.

    in the project i'm working on, i have to add solar and battery power options to the equipment that normally runs from a power line. not an easy task, but fortunately there are a lot more devices today that can do the job.
     
  2. chemelec

    chemelec Well-Known Member

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    Yes But Inverters, Solar Cells and Batteries is NOT a Very Practical Solution.
    Its Expensive, Needs Constant battery Up Grades and a Very LOW Efficiency.

    Much more practical is a Parabolic Mirror or other Mirror Setups to Heat Water. Than convert that heat energy to electricity.
    I'm Not Sure on How it Converts to electricity, But it is being done in numerous places now with quite good efficiency and lower cost than Solar cells and batteries.
     
  3. koolguy

    koolguy Active Member

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    Is there any difference in Microwave transformer then other, and where these transformer are used??
     
  4. dave

    Dave New Member

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  5. audioguru

    audioguru Well-Known Member Most Helpful Member

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    A microwave oven transformer is rated at 700W to 1000W which is probably much higher than your cheap little transformer.

    But since a microwave oven is turned on only for a few minutes at a time then it probably also has a cheap transformer that over-heats if it is used for a long time continuously.
     
  6. chemelec

    chemelec Well-Known Member

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    Old Microwave Transformers are usually easy to find and they are Easy to Remove the Secondary, so easy to Rewind.

    Maybe your transformer will also work. But We don't know What its Specifications are?
    (Current and Voltage Ratings)

    Give it a Try.
     
  7. koolguy

    koolguy Active Member

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    I have connected 7809 ic with Transformer Rectifier of 18V, 7amp. the ic was burn out when I connected it with supply, with no load !!
     
  8. chemelec

    chemelec Well-Known Member

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    Well Either you Connected it INCORRECTLY, Or you had MORE than 18 Volts DC
    Or you didn't use any "Filter Caps" and you had a LOT of AC Ripple.

    Before you Continue to BURN OUT PARTS AND WASTE YOUR TIME AND MONEY, I SUGGEST YOU LEARN SOME BASICS of ELECTRONICS!

    The 78XX Regulators are good Up to 30 VDC IN.
    And Typically Rated to Pass about 1.5 Amps to the Output.
    (Unlimited Source Current.)
     
  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The datasheet for a 7809 shows a very important input capacitor and a very important output capacitor that you must add to prevent the IC from oscillating.
    The datasheet lists a max allowed input voltage of 35V but 25V is recommended. Your transformer's voltage might be as high as 22V without a load then when rectified and filtered it will produce about 30V which is high but is fine.

    Since your regulator burned then either you connected it backwards or it was a counterfeit one.

    With no load a 7809 draws a max current of only 8mA. Its typical current is only 4.2mA. It has thermal shutdown so if it gets hot it will shutdown to protect itself.
     
  10. unclejed613

    unclejed613 Well-Known Member

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    or he connected 18Vac to the 7809.... that will let the smoke out quickly
    Stancor (as well as many other manufacturers) makes a line of transformers with the name "Rectifier Transformer" right on the label, and 18V/7A, while it isn't on the first page i pulled up, is well within the output voltage and current range generally classified as a "rectifier transformer" which is a broad range of transformers used for open-frame regulated DC power supplies. the kicker here is that Stancor actually put a note on the page saying "(note: rectifier not included)"...
    and this is what makes English one of the most difficult of languages.... the adjective comes before the subject. a "rectifier transformer" is not a "transformer rectifier" because the first implies that the transformer is designed to be used with a rectifier, the second implies that the rectifier is already attached to the transformer.... so a "rectifier transformer" has an AC output, and a transformer rectifier has a DC output.


    i'm familiar with the term "rectifier transformer" because i had to find a replacement for a 24V/10A transformer that NCR used in some of their banking equipment. NCR wanted to charge our service company over $100.00US each for these when the original ones began failing. i was able to find one from Stancor for about $20.00 each with only a minor difference in the spacing of the mounting holes.
     
    Last edited: Oct 19, 2010
  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Since the kid "No Speeky Zee Engrish" very well then maybe he should not be here.
    Maybe he connected his 7809 regulator to his 18VAC transformer without a rectifier.
     
  12. chemelec

    chemelec Well-Known Member

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    First and foremost, this person needs to "learn basic electronics".
     
  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    But since he talks to us "Westerners" then he needs to also learn English.

    This is a big world.
    There are us and there are them. Completely different.
     
  14. koolguy

    koolguy Active Member

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    ok, i have connected 7809 IC to transformer rectifier of 18V dc and 7 amp. (max), I have connected +ve supply of rectifier to pin 1 , gnd to pin 2 And output from pin 3.
    The rectifier i am using is bridge rectifiers, I have not connected any capacitor to input and output side of regulator(7809) and as i connect the Supply(DC) temperature increases and IC burn out!!!!!!
     
  15. chemelec

    chemelec Well-Known Member

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    Just Adding a Bridge Rectifier to a Transformer Does NOT MAKE DC.
    The OUTPUT Still Contains a LOT OF AC.

    YOU MUST PUT A "FILTER" CAPACITOR Between the Positive Out to the Negative.
    And it Should be at LEAST a 1000uF Capacitor.


    As well as a 1uF Tantalum Cap at Both the Input and Output of the 7809

    ALSO, What is the Rating of Your Transformer?
    Is it 18 Volts AC?

    And IF it is 18 VOLTS AC, your Output When Rectified and FILTERED with the large Capacitor, Will be About 25 VOLTS or more with No Load.

    YOU NEED to GET SOME BASIC ELECTRONICS "EDUCATION"!
     
  16. koolguy

    koolguy Active Member

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    So, what....................................??????????????????????????????????????????????
     
  17. magnatro

    magnatro New Member

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    The infrastructure development in India is far less than the developed country. India uses more than 70% of income for defense of borders.
    the power shifting is done in so called "peak hours" when the electricity consumption is very high ( i think between 6 to 10 )
     
  18. magnatro

    magnatro New Member

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    the 7809 will not burn out unless it's polarity gets reversed..
    it's a very reliable IC with temperature compensation so you HAVE to filter the DC peculiarly because it's of higher amps rating.
     
  19. magnatro

    magnatro New Member

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    There are us and there are them. Completely different?
     
  20. magnatro

    magnatro New Member

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    This is one of my designs.

    inverter.png
    the output must be interface with 3055 transistors mounted on proper heat sinks.
    the thermistors are to be replaced with resistors. (assembled in a hurry)
     
    Last edited: Oct 26, 2010
  21. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I don't want to go into details but you know what I mean.
    I am a westerner in Canada.
    People in India look different, dress different and eat different then they even smell different.
    They speak in about 23 languages that are completely different from Enlglish.
    Their tiny little 3-wheel "cars" are different.
    Their electricity barely works for only half the time.
     

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