Looking for a PS

Discussion in 'General Electronics Chat' started by lippy, Sep 18, 2012.

  1. lippy

    Thread Starter New Member

    Jul 17, 2012
    4
    0
    I'm trying to track down a 120VDC power supply capable of supplying about 350mA for 2-8 minute intervals. I'm considering building a linear supply with an isolation transformer, rectifier and a pass regulator but I'm concerned about heat and inefficiency. I've poked around looking for an off-the-shelf switching supply but the cost may be a deterrent.

    Anybody have any thoughts on building a supply capable of that type of power and/or know where I could pick up a reasonably priced supply out of the box?

    Cheers!
     
  2. timescope

    Member

    Dec 14, 2011
    298
    44
    You could ask a TV repair technician for a CRT TV power supply. The supply to the line output transformer (100v -145v depending on the screen size ) should be adequate for your application.
    Timescope
     
  3. sceadwian

    New Member

    Jun 1, 2009
    499
    37
    What is your voltage compliance tolerance? And why 2-8 minute intervals?
     
  4. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Look for used rack mount bench supplies from Power ten, Electronic Measurements Inc (EMI), Lambda, etc.

    Or, check ebay but all their no-name electronics are made in China so you take your chances.
     
  5. lippy

    Thread Starter New Member

    Jul 17, 2012
    4
    0
    @ Sceadwian the tolerance isn't super-tight. I need an absolute minimum 115VDC, max could be up to 130V, and relatively stable (within a couple of volts with a constant load). The 2-8 minutes is due to me wanting this thing to drive a motor and it takes roughly 2-8 minutes, depending on the condition of the motor, for it to do it's thing.
     
  6. sceadwian

    New Member

    Jun 1, 2009
    499
    37
    Couple of volts, okay that's what was looking for! =) 2% tolerance on a 130V DC variable power supply capable of 500ma (saftey value)

    All you need is a 50VA variac fed through a bridge rectifier and a capacitor to buffer it a little. You could probably piece something like that together for dirt cheap.

    http://www.ebay.com/itm/GENERAL-RAD...988?pt=LH_DefaultDomain_0&hash=item43b384ce04

    Would be one variac that would work, 10 bucks. Bridge rectifier for that would cost I dunno 5-6 bucks? Cap 2 bucks for a nice big one.

    A bench supply is too precise (often .1% sometimes 1% for super cheapies) but you can look if you want, a quick and dirty variac/bridge/filter cap will more than meet your needs.
     
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