Laser power Supplies

[Banthai]

heres my tuppenths worth .. and just my personal opinion ( so it dont mean much )

Im dead against a common single PSU ....

Why ? you may ask ....

if you are doing a paid show somewhere and say .... your blue Diode or Driver goes short circuit .... and takes out the PSU ... END OF SHOW... no money

if you have individual PSUs .... you would at least be able to complete the show in green and red ..... chances are ...not many people will even notice that you have lost a laser ...

ok ther are lots of other areas for failure... scanners.. PC ... etc
but i think it does minimise the risks

all the best .... Karl

[loopee]

Hi Guys

Thanks for all the feedback

Karl, to be honest I totally agree with your logic for this especially for a production system, I was first thinking of using a modular power supply for easy swap over but it turned out to be a tad cost prohibitive.

I mainly wanted to go to a single power supply for simplic of design of my projector and at this point I'm not looking at doing comercial work, so a power supply failure won't worry me to much (unless it takes out the lasers)

Stan, its interesting that you mention that the Laserwave power supplies are only capable of suppling 8A as my 250mW blue draws 8A, so the supply does get warm

So now I have a 5V 30A supply, Hopefully more than enough for the three lasers.

BTW, Does any one know what the typical current draw in for red? somewhere in the 500mW to 800mW (635 or 660nm)

Troy

[FrankenPC]

Hi Guys

Thanks for all the feedback

Karl, to be honest I totally agree with your logic for this especially for a production system, I was first thinking of using a modular power supply for easy swap over but it turned out to be a tad cost prohibitive.

I mainly wanted to go to a single power supply for simplic of design of my projector and at this point I'm not looking at doing comercial work, so a power supply failure won't worry me to much (unless it takes out the lasers)

Stan, its interesting that you mention that the Laserwave power supplies are only capable of suppling 8A as my 250mW blue draws 8A, so the supply does get warm

So now I have a 5V 30A supply, Hopefully more than enough for the three lasers.

BTW, Does any one know what the typical current draw in for red? somewhere in the 500mW to 800mW (635 or 660nm)

Troy

This is a wild guess as I've never had a red LASER in that power range. But, working upward from a 150mw red I have, I would guess 300-500ma?

EDIT: Not including the TEC power requirements which can be pretty high.

[buffo]

For what it's worth, Maxyz modules (~ 200 mw of 660 nm red) typically draw around 300 ma.

As for the common power supply idea - I know of lots of people that have built their projectors this way. And when you think about it, which is more likely to fail? A dedicated (and very robust) 15 amp power supply, or the small (and cheap) laptop PSU's you see included with every Chinese DPSS laser?

If you fuse the PSU correctly, a direct short will not kill it. So the only way it's going to die is when it wears out from old age. And that's not likely to happen.

Adam

[MechEng3]

Even if it takes out my 25 amp, 5vdc unit.....I have two spares...I hope I never see a driver short soo bad that it doesn't catch fire or open the short with this power level available. No problems in 2 years running the Meanwell supplies.

[carmangary]

Most decent power supplies have short circuit protection. I know mine does.

[heroic]

heres my tuppenths worth .. and just my personal opinion ( so it dont mean much )

Im dead against a common single PSU ....

Why ? you may ask ....

if you are doing a paid show somewhere and say .... your blue Diode or Driver goes short circuit .... and takes out the PSU ... END OF SHOW... no money

An 8A driver on a 30A supply should be protected by a 10A fuse anyway. There's no way it can even conceivably take out the whole PSU. Even if it failed dead short it'd just pop the fuse.

(Yes, you should have separate 5v fuses, rated for DC, for each separate module that attaches to the main PSU. Car and truck electrics suppliers are a good place to find fuses that will work with DC.)

I understand your skepticism about this, but really modern SMPSUs are some of the most reliable components in the world; they're used everywhere and work very well.

[Banthai]

i understand what you are saying .... and this is why i said ...

and just my personal opinion ( so it dont mean much )

but it does come from personal experience as i had a pump diode go short circuit a few years back and took out a Lambda power supply ....

because of that, in my RGB i know if one psu fails for a laser head... i still have other colours

thats why i have a poly20 grating wheel as well .... if the scanners fail or the PC fails ..... i can still do some kinda show

as i said its just minimising risks of... having a show fail half way through

oh .... and if my safety shutter psu fails ..... im buggered


all the best ... Karl

[heroic]

Right but still, if each diode driver has a separate fuse, at worst any one failure's going to take out just that one diode driver.

[dave]

If you fuse the PSU correctly, a direct short will not kill it. So the only way it's going to die is when it wears out from old age. And that's not likely to happen.

All well designed switch modes have short circuit protection. They will just sit there ticking, as they current limit.....