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Thread: High Output Coherent Diode Lasers, I Need Some Help!

  1. #31
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    see if there is any maganin on ebay before you use nicrome.

    Steve

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    Quote Originally Posted by mixedgas View Post
    see if there is any maganin on ebay before you use nicrome.

    Steve
    Hey Steve!

    The only "magnin" I can see on Ebay is woman's dresses. What is that, Magnesium/nickel? I already bought some thick nichrome ribbon on ebay a few days ago. I was thinking to use 2 or 3 long strands of that (set to a particular resistance) to get the value and current handling I need without the nichrome turning into a heating element.

    What do you think, Steve?

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    Quote Originally Posted by 300EVIL View Post
    Hey Steve!

    The only "magnin" I can see on Ebay is woman's dresses.
    I think he meant Manganin. It's a copper-manganese-nickel alloy, and it's what you want because it has a very low thermal coefficient.

  4. #34
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    Quote Originally Posted by heroic View Post
    I think he meant Manganin. It's a copper-manganese-nickel alloy, and it's what you want because it has a very low thermal coefficient.
    AH! Okay, now I got it. Thanks for the help guys!

  5. #35
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    Since ion laser power supplies are suicidal soon after birth, ion laser techs are quite fond of these. Seriously, I've had to rebuild quite a lot of metering cards for Lexels. You get huge impulses when 30A of 3P lets go in a uncontrolled mannor.

    Cheaper then winding you own.

    http://cgi.ebay.com/20A-75mV-DC-Curr...QQcmdZViewItem


    Enjoy, Steve

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    Hey Steve,
    Yes, already got one on the way from China. It's a 200A shunt with digital readout. I just need to figure out my low resistance power resistor.

    The nichrome ribbon I got in yesterday looks like it will do the job quite well as long as I use multiple strands. It takes a lot of current before it begins to glow. We'll see.

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    You'll probably laugh at me, but i used good old fashioned coat hangar wire as a ballast for the lower power 60W laser diode. The reason i chose it is because it was easily brazable, can take a lot of current and has a resistance between copper and nichrome.

  8. #38
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    Quote Originally Posted by heruursciences View Post
    You'll probably laugh at me, but i used good old fashioned coat hangar wire as a ballast for the lower power 60W laser diode. The reason i chose it is because it was easily brazable, can take a lot of current and has a resistance between copper and nichrome.
    Yeah, You mentioned that to me at the swapfest. You can't beat stuff that just works sometimes. However, I'm in no rush to get these diodes running and I'd rather not blow them with a crude power supply rigging. Also, I'm looking froward to building a nice high current variable driver for them.

  9. #39
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    FAIL.....

    Well I built the circuit in the schematic a few posts back from Sam's Laser FAQ. I can only vary the current by 10 amps so this won't work. (130A @ 2.5V) In defense of the schematic, it was designed for a particular high current switching PS that is not the same as mine. On top of all this, I smoked my digital current meter I got from China so testing is now over. Turns out the input supply is not isolated from the current metering...

    I'm at a loss here. I spent over $100 on all these parts to try and make this work but I can't figure it out. Can I just pay someone to draw me up a schematic of what I need to build to make a 0-100A PS? All this shot in the dark stuff is aggravating.



  10. #40
    mixedgas's Avatar
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    UNFAIL.....

    what kind of cooling am I allowed?

    Size restraints?

    Do you have a 5V 100 amp supply?

    my next available time frame is 2 weeks.

    Steve

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