Regulator(s) for 15 Amp power supply

Thread Starter

sparky01

Joined Aug 31, 2008
1
Hello all,

New to the forum. I'm building a 30-32 VDC @ 15A power supply for a recently acquired toy......actually "toy" might be the wrong word for a 25 watt CO2 laser:eek:. And, yes, I have protective eyeware!

So far, I have the transformer, bridge rectifier, filter cap, chassis & misc parts & pieces. At full output, the laser uses 30-32 VDC @14 amps. Can I put LM338 regulators in parallel to reach the current needed. Would three be sufficient, or would that be cutting it too close?

I was looking for a switcher, but they are WAY too expensive.

Thank you for your help!
Regards,
Sparky01
 

RmACK

Joined Nov 23, 2007
54
You could use a high current rated transistor to take most of the current, the regulator simply controlling it with a much smaller current. See attached though component values will vary depending on your transistor and the supply voltage.
 

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SgtWookie

Joined Jul 17, 2007
22,210
Lasers generally require very tight tolerances on the current they're fed.

Give 'em just a tad too much, even for an instant, and you have some interesting trash can filler. It happens that quickly.

You might have something valuable, or you might just have a piece of junk. If you experiment with it without knowing what you're doing, you could wind up getting hurt along with having a piece of junk.

I do not claim to be experienced with lasers. I know how to get myself in trouble with them. However, this guy IS experienced with lasers:
http://www.repairfaq.org/sam/
Read his experiences, get to know him.

What you have there requires a lot more research than just a quick & dirty answer.

Please be careful. Do your research.

It really isn't a toy. You could easily wind up blind or dead if you make a mistake.
 

Wendy

Joined Mar 24, 2008
22,155
We used to use 10 Watt CO2 lasers at Alcatel to solder optical components (after precision alignments they didn't want a physical soldering iron messing things up). Their max was 15 Watts, we use a 555 PWM to scale em back. These units had matching power supplies, we didn't manufacture them a bit, but added the interface to adjust power as has been mentioned.

I was the lucky guy who got to check them, and if they weren't right, pull them and send them to a specialist.
 
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