High power blinker

Discussion in 'General Electronics Chat' started by Munkhtulga, Apr 15, 2015.

  1. Munkhtulga

    Thread Starter New Member

    Apr 15, 2015
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    hey guys, i need some help. i need a blinker LED scheme. but scheme parameters must be high as 220V and current is high at least 5 A. is there any way to solve this problem?
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    do you have a dc power supply, also what is the blinker for?
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    If you're thinking of driving the LEDs directly from mains voltage, that's a banned topic on this site.
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    feed us more details..
    we are starving here...
    schematic?
    led specs Vf/current?
    etc...
     
  5. Munkhtulga

    Thread Starter New Member

    Apr 15, 2015
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    Hello dodgydave, i have 220V DC power supply. it is supplied by batteries. so i need blinker for Automatic transfer switch signal. if Automatic transfer switch worked, led ,must be blinking. problem is our circuit load is very high. blinker circuit must withstand least 5A there is any way to solve this problem buddy?
     
  6. Munkhtulga

    Thread Starter New Member

    Apr 15, 2015
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    it needs for transfer switches signal. if it is worked led will blink. just what details do you need?
     
  7. Dodgydave

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    Jun 22, 2012
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    like what is a transfer switch?, have you got pictures!
     
  8. gerty

    AAC Fanatic!

    Aug 30, 2007
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    For continuous duty blinkers, solid state relays last the longest. We need to know the rest of the facts about what you're doing.
     
  9. mcgyvr

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    Oct 15, 2009
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    LED Specs? (Vf and rated current mostly)
    Transfer switch signal specs? dry contact? open collector?,etc...
    Required blink rate?
    etc...
     
  10. ian field

    Distinguished Member

    Oct 27, 2012
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    If you can find a scrap TV with a flyback SMPSU (old CRT type) the MOSFET is probably rated 600V 6A - as long as its switched between fully on and fully off (no linear region dissipation) and has a decent heatsink, you should be able to do that.

    Also CRT PC monitors, anything over 15" should have an adequately rated MOSFET - some of the bigger monitors have a chunky TO3P rated upto 900V and 8 or 9A.

    Shouldn't be any difficulty driving the MOSFET with a simple 555 pulse generator - but do look at the MOSFET datasheet and confirm how much gate voltage is required to achieve the headline RDSon/Id-max. You probably need to aim in the general direction of 8 - 10V, most MOSFETS have a maximum gate voltage around 18 - 20V - anything over that and the life expectancy takes a hit.
     
  11. gerty

    AAC Fanatic!

    Aug 30, 2007
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    Do you know what type leds you'll be using? If insert name/ number here___________
    Do you know what power supply you want to use? If so insert ratings here___________
    Do you know how fast you want to flash it? If so insert numbers here_________
    Fill out the form and we might be able to help, otherwise.........
     
  12. tcmtech

    Well-Known Member

    Nov 4, 2013
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    I am taking it that all you really need is a indicator LED to blink not the whole power supply load.

    If so I would just use a common universal input (90 - 250 VAC input) USB type charger or some other similar universal power input converter to convert the 220 VDC down to a 5 VDC level where it can then run a self blinking LED.
     
  13. ian field

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    Oct 27, 2012
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    Actually - come to think of it: A typical flat screen TV or monitor will probably have a half-bridge SMPSU, The MOSFETs will probably only be rated at 500V, but that won't be a problem with a 250V battery supply. Probably depends on screen size, but I'd expect the MOSFETs to be at least 6A.
     
  14. Munkhtulga

    Thread Starter New Member

    Apr 15, 2015
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    it is an inter sectional transfer switch. For example if sectional power supply damaged or fallen, reserve power supply must be switched on. then if transfer switch worked LED must blinking and give us signal. our signal system works on 220 or 110 V DC power supply. then signal load is too high as 5 A least. i ll sent you schematic soon.
     
  15. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Slowly we're getting there (I think) :rolleyes:. Do you already have a signal to control the transfer switch to cause it to operate? We really do need a schematic of the system, to put an end to this guessing game.
     
  16. tcmtech

    Well-Known Member

    Nov 4, 2013
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    I am not so sure we are getting anywhere yet. So far I am seeing either a language barrier and or a possible electrical fundamentals understanding problem.

    As I see it the OP has a power system of some sort that runs on 110 VDC and 220 VDC at up to 5 amps for part of its systems but is only needing a simple blinking LED to come on when ever the backup power source is being used.
     
  17. ian field

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    Oct 27, 2012
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    If you simply want a current draw indicator at around 5A-ish, you can put a series chain of power rectifiers in series with the load to provide a clamped volt-drop to feed an indicator LED. Obviously the rectifiers must handle the maximum current draw with a decent safety margin. About 3 series silicon junctions will do for a red LED Vf, you can adjust the number of junctions to suit the LED type, its not a bad idea to include a safety resistor in series with the LED to absorb any spikes; about 33 - 56R should do. You can get blinking LEDs with a built in flasher chip, but they need at least 5V - quite a few Si junction forward drops to get enough!

    If its an AC supply - you need one more power rectifier - that goes in inverse parallel with the "series rectifiers/LED/resistor" combination. That makes sure the other AC half-cycle can get to the load and protects the LED from excess reverse voltage.
     
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