Does a devise like this exist

Discussion in 'General Electronics Chat' started by Bobert1850, May 2, 2018.

  1. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    I'm looking for something that will take 12-24v input and vary the output between 0-120v. Like a variable transformer? And if it don't exist, is it possible? It would make my life so much easier.
     
  2. RichardO

    Late Member

    May 4, 2013
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    Do you want AC or DC in? AC or DC out?
     
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  3. BR-549

    AAC Fanatic!

    Sep 22, 2013
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    What kind of volts?
     
  4. BR-549

    AAC Fanatic!

    Sep 22, 2013
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    Where is the 12-24v coming from and where is the 0-120v going to?
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    current levels?

    Its unlikely to find something like that though.. Doable.. unlikely to commonly found anywhere..
    I wonder what the application/use is?
     
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  6. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Reverse-connected Variac autotransformer.

    ak
     
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  7. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    It's all dc. The 12v in is from a lead acid battey or 2 in the case of the 24v. It' for running a 2000w dc 0-130v motor
     
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  8. crutschow

    Expert

    Mar 14, 2008
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    That's 167 amps from a 12V battery or 83 amps from 24V.
    Your batteries won't last long. :rolleyes:
     
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  9. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    It don' have to last long and the speed will be varied. I do plan on using li-ion down the road.
     
  10. BR-549

    AAC Fanatic!

    Sep 22, 2013
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    Can another method, something else provide motor function?

    Is this for loss of AC or normal operation?

    Got any more batteries?
     
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  11. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    It is mostly for remote operation. I was looking into a power inverter but I can not find one that is single feed out. Plus it don' make sense to me to go from dc to a.c. and back to dc. The motor controllr I have now uses 110 a.c. input and 0-110vdc output
     
  12. WBahn

    Moderator

    Mar 31, 2012
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    How long is not long? You would probably not get more than a few minutes from a typical car battery, for instance.
     
  13. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    In reality I'm not too concerned about battry life. I have seen electric bicycles with equivalent wattage motors that have a 20+ mile range. If I can get 1/4 of that power, i would be happy. I could use their controllr but they are made SO cheaply, there has to be better out there
     
  14. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Really? A bicycle with a 2000 W motor? I've seen 1000 W, but not 2000.

    ak
     
  15. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    2 kW seems like a lot to ask of a beefed-up boost converter circuit. I think there is a transformer in your future.

    High power / high density DC/DC converters are good for around 500 W per brick. Some have a wide output voltage adjustment range (but I don't recall any that regulate down to 0 V). Some can be paralleled. Some can be stacked up, such as two 48 V output bricks with inputs in parallel and the outputs in series to give 96 V. You need all three features, which will take some digging.

    Vicor, SynQor, Astec/Tyco/Artesyn/whatever

    You might have to go with a fixed-output boost stage of whatever technology, followed by a synchronous buck regulator for the variable output to the load. The very-wide output voltage range almost certainly means a very wide output current range, and that will make the magnetics a ... challenge.

    ak
     
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  16. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    I said comparable, and by that I meant close. To be honest I have not seen over 1500w but even then, they still have a fair range. With li-ion batteries, I don' think I'll have much of a problem. I'm very rusty when it comes to all this and I never learned much to begin with. I really want to keep this project cost down by salvaging most of the parts. I got the motors for free from treadmills and I figured it couldn't be that hard to run off of a car battery. I have seen people build gokarts from starters and Ik that would require atleast 4hp. I'm only trying for just under 3
     
  17. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Yeah, but there is a big difference between running a 12 V motor on a 12 V battery, and running a 110 V motor on a 12 V battery. Bringing in the whole system for under $1 per watt will be difficult unless there are some super-cheap ebay modules that just happen to fit this application.

    ak
     
  18. Bobert1850

    Thread Starter New Member

    Apr 29, 2018
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    But I can buy a 3000w inverter for a few hundred and run it off that. I' just trying to save a step and avoid having to convert to a.c. and then back.
     
  19. -live wire-

    Active Member

    Dec 22, 2017
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    BR-549 likes this.
  20. -live wire-

    Active Member

    Dec 22, 2017
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    Can you also please stop creating so many threads for the same topic? It can be confusing and is borderline spam. Thanks.
     
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