How to convert three phase AC into single phase ac or DC ?

Discussion in 'The Projects Forum' started by Ujwal Bhagat, Jun 4, 2016.

  1. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    Hey guys, I'm back with new project. Now I want to get single phase ac from a two wheeler's alternator or DC. Because I'm gonna use it as a inverter, I want 220v 50-60hz ac or 12v 60watt(nearby). I don't know the alternator capacity, though I know one thing that it can at least generate 5amps DC, I checked this with my multimeter. Any thoughts will be appreciated !
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    Did you know that 12VDC to 220VAC inverter can take more than 5 amps to power a simple house hold appliance.
     
  3. crutschow

    Expert

    Mar 14, 2008
    13,014
    3,234
    What do you want to power with the 220Vac?
     
  4. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    So all you need is a three phase rectifier, smoothing capacitor (and regulator?) and an inverter of course.
     
  5. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    Yeah, up till now I have been using my inverter to power 7 watt led bulb using my two wheeler's battery charging circuit. I cannot get more than 5 amps through it. That is why I thought that making my own rectified bridge or converting phase, would be more promising !
     
  6. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    Table fan and a led bulb. I need at least 50 to 60 watt !
     
  7. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    Yeah I know that, but I don't know any specific values so any help will be appreciated ! By the way I have my inverter.
     
  8. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    6 off diodes 10A+ 100V+ should be more than adequate - that's the easy bit.
    The size of capacitor needed depends on the frequency of the alternator - which is?
    What is the input voltage requirement of the inverter (min-max)?
    What peak voltage does the alternator provide at 5A?
     
  9. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    Thanks, please provide circuit diagram. I don't know the frequency so suggest me something. Min 12v at 10.5v inverter stops and gives battery low warning and max is 13.5v. How can I measure the output of alternator ? and I didn't mention that it provide 5amp max! I said that the rectified DC output was 5 amps, I checked it attaching my multimeter in series with battery when engine was running and battery was charging.
     
  10. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    Search www for 3-phase rectifier - lots of diagrams there.
    Does your two-wheeler have a rev counter? If so how fast was it running when the alternator was providing 5A (that will give some idea of the frequency).
     
  11. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    No, no rev counter. Sir the 5amp was restricted by the charging circuit and the engine was little more than idle as I was giving very low amount of gas!
     
  12. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
  13. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    Hang on a minute. You could simply connect the inverter across the battery with the engine running to keep it charged. The rectifier, smoothing and voltage regulation are then built in.
     
  14. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    I was doing the same, but I can't run more that one bulb and torch charger. I want to run the table fan.
    Though I have a idea, the capacity of the battery is 5ah, if I buy a 10ah battery and connect it in series it would increase the capacity. The charging circuit will ensure that the battery will give good battery backup.
    According to my calculations, 15ah at 12v will be 180 watt. After converting into AC keeping in mind about the inverter efficiency output wattage will be 50watt at least. Right ?
     
  15. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,800
    1,103
    ...... but only for 1 hour (theoretically). You are confusing Ah (Ampere-hours) with A (Amps).
     
  16. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    The two wheeler charging circuit will slow down the discharging process.
    Because when I was using my inverter directly in parallel will the two wheeler's battery when engine was running I got infinite backup until the fuel runout or engine stops.
    So I think it would provide more than 1 hour backup. Correct me if I am wrong.
     
  17. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    Yes, providing you take no more current from the battery than the generator can replace.
     
  18. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    So it means it can give at least 1.5 hour backup if I run table fan on it?
     
  19. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    How much current does the inverter take from the battery when running the fan?
     
  20. Ujwal Bhagat

    Thread Starter Member

    Jan 30, 2016
    76
    0
    More than 5amps, I don't know the exact value since inverter shows battery low warning after 1 or 2 sec of connecting fan. Wattage of table fan I really don't know, but it must be between 30 to 50 watts.
     
Loading...