# Inverter.........!

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

1. ### koolguyActive Member

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I want to ask Some Inverter have High Current while some Work On High Voltage Why.........?

2. ### crutschowWell-Known MemberMost Helpful Member

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Depends upon what you need in your system.

3. ### audioguruWell-Known MemberMost Helpful Member

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An inverter uses the DC power from a battery to make higher voltage AC power.
Power equals voltage times current so for 1000W a 12V battery must supply 1000/12= 83.3A and its 240V output current is 1000/240= 4.17A.
The inverter uses some extra power for its circuits so if the output is 1000W then its input from the battery might be 1200W and the extra 200W makes heat.

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5. ### koolguyActive Member

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I my home Inverter is Using 12 Battery Of 12v & Near about 7amp The o/p Rating is 5KVA as It Is Used For Driving Flex Printing Machine & in Simple inverter i have seen It use 1 or 2 Battery Of High Current (Big Size) why.?

6. ### audioguruWell-Known MemberMost Helpful Member

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If your inverter draws only 7A x 12= 84A from a 12V battery then its output power is less than 12 x 84= 1kVA, not 5kVA.
If it actually has an output of 5kVA then its current is 5000/12= 417A or more from a 12V supply.
A battery that can supply 417A is huge.

What is wrong with your electricity? Why do you need to use a battery and an inverter? My electricity is reliable and is always there. I have never used and have never needed an inverter.

7. ### Ubergeek63Well-Known Member

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actually from what i have heard in a lot of countries the power is intermittent at best... being out for over an hour a day might be common.

8. ### audioguruWell-Known MemberMost Helpful Member

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What is the matter with the people who are paid to make sure that the electricity continues to work properly?? Are they always drunk?
Do they use mules (or people) pushing a generator but forget to feed the mules (or people)??

My reliable electricity comes from buried wires. Nuclear and waterfall generators power the wires. There are only a couple of huge windmill generators.

9. ### Ubergeek63Well-Known Member

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you are in canada and i in the us. we are used to whining about it on the rare occasion ours goes out. he is in india...

10. ### Rajagopal87New Member

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Here in india power outages are very common... Typically every household invariably in any city all thru the country faces 2 to 3 hours of outage daily.. Simply because we dont have sufficient generators to feed all people... So they shed loads in turns.. Power from a generator for one place in morning and for some other place in evenings...!

@audioguru: I am surprised to know that its a surprise for you...!

11. ### audioguruWell-Known MemberMost Helpful Member

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This is the year 2010, not 1810! Why is India so far behind every other country?
In Canada people work, pay taxes and pay utility bills. The money collected pays for upkeep and additions in the electricity system.
Don't people in India work, pay taxes and pay utility bills like everybody else? Why not?

12. ### Rajagopal87New Member

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In india, majority of power comes from thermal power stations with coal as main fuel. The hydel and wind power are seasonal. And a thermal plant needs a minimum of 3yrs to setup. The present shortage of power may be attributed mainly because of improper planning and execution of power projects. Also the capacity of power plant equipment manufacturers are limited which sets limits to the maximum addition possible. Though we indians are willing to pay money(like anybody else, we do work,pay taxes and utility bills..) power is not available simply because there is no source. The gap keeps growing and in many cities people have resorted to their own power sources(like battery inverter setup etc..) owing to the unreliability of grid power. Even industries here suffer hugely because of the power crisis!

btw, I work for a thermal power plant equipment manufacturing company.

13. ### koolguyActive Member

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We can connect Battery in // & series What will happen? As I have connected battery in series Voltage Increases But in // It spark Why........?

14. ### koolguyActive Member

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Pls tell The Circuit in which Mosfet Is Used For Giving o/p, To The terminal of Transformer & Why The Metal Body of Mosfet is Connected To Source of Mosfet ........?

15. ### Ubergeek63Well-Known Member

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they are at different voltages, they need to be balanced as well as matched.

16. ### audioguruWell-Known MemberMost Helpful Member

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There are many simple square-wave output inverter circuits using Mosfets on the internet. But many electronic products need a sine-wave and do not work properly when powered by a square-wave. The square-wave inverter uses a huge, heavy and expensive low frequency transformer.

Newer inverters also use Mosfets but produce a pure sine-wave. They use a high frequency inexpensive lightweight transformer and Pulse-Width-Modulation to synthesize the low frequency sine-wave.

Look at the datasheet for a Mosfet. The metal tab is connected to the drain, not the source.

In my part of Canada we removed a few coal-fired electricity generating stations because they produced terrible air pollution.

Here is the pic of an old Mosfet from its datasheet:

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17. ### koolguyActive Member

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I thick O/p Is taken from Source in mosfet.......!

18. ### audioguruWell-Known MemberMost Helpful Member

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Usually the output of a Mosfet is its drain. Then it has voltage gain.
If a Mosfet is used as a source follower then it has no voltage gain and its gate voltage must be up to 10V higher than its output voltage.

19. ### koolguyActive Member

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I have Doubt that, That we can take O/P From Drain or source It's possible...?

20. ### audioguruWell-Known MemberMost Helpful Member

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An ordinary Mosfet Needs its gate-source voltage to be 10V for it to completely turn on.
If the source of an N-channel Mosfet is grounded then a 10V or 12V signal at its gate will completely turn it on so that its drain goes down to ground.
If the load is connected to the source of an N-channel mosfet then the gate must be +22V for it to completely turn on if the supply is 12V.
Where will +22V come from?

21. ### koolguyActive Member

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ok, you want to say that on connecting load across drain, the supply voltage to gate will be low & good, & which mosfet is ordinary pls explain.!