Projector Power Supplies

[andy_con]

what one big one then dc/dc convertors?

[kitatit]

Yes they look nice!

The DC-DC route might be possible.

The multi output supply in my projector works like that but it was blood kurdlingly expensive.

I think power efficiency issues dictate which is the best way to go.
My knowledge is fairly basic with these issues.

I'm hoping the guys who know what they are talking about will chime in.

I'll be talking out my ass if I claim to know anymore than this

[andy_con]

dc/dc 5v and 12v are very eeasy to sort, its this 24c +/- that has confused the fudge out of me

[WookieBoy]

Andy,

If I remember my electronics correctly (and it's been a while since I used any of it in anger, so I may be wrong here) you should be able to get a 48v psu and use voltage converters to get +24v/0v/-24v fo your scanners then you can take a second tap off the 48v and dc/dc convert it for the 12v and 5v or whatever as required.
The only tricky part is balancing the +/-24v section I think, 'cos if memory serves, I read somewhere that scanners can get picky about their current draw being interfered with if it's not even on both the + and - rails of their PSU...
Please someone with less cobwebs in their brain, chime in and correct me if I'm wrong on any aspect of the above!

Looking at my SwissLas unit, the little separate PSU block it runs from is a 48v dc supply, so I'd guesse that's how they do it as well...

[kecked]

I have an error in this post: NO NOT TIE THE CENTER OF THE SUPPLIE TO EARTH GROUND. This point has to float to make this system work. DO TIE THE CAGE TO EARTH GROUND THOUGH. just not the dc center between the supplies.



not sure about your scanners, but 6210s need 24v with 6A peaks and they like 28V 6A. Thats EI=W or 24*6=144W 28*6=168W peak. That's for each power supply so the whole system is dumping over 250W. Don't skimp on your scanner supplies. The way scanners work is that they need a lot of power to move a scanner mirror from one point to another point and lot of power to stop the mirror on the point to prevent it from over shooting.

DC-DC convertors could work for lower current lasers but you might as well use a decicated supply and not rob your scanners. Your images will thank you.
I put this on a separate line because it is soooo important.

MAKE SURE YOU TIE ALL GROUNDS TO A CENTRAL POINT AND TIE EARTH GROUND TO THE CENTRAL GROUND. ADD FUSES ON THE MAINS SIDE.
Don't take the supplies out of the cages. They need them to stop all the higher frequency hash they make from getting out of the projector. If you have to remove thm from the cages make a solid metal box over the naked supplies. Copper foil tied to ground will work well.

Last if you decide to put your power outside of the projector. Don't. There are a ton of reasons not to do it. Noise being the main one. If you have to keep go outside keep the line short under 3-6 feet and use a shielded cable. Put a 0.1uf cap on all legs going and coming from the supplies.
Did I say :MAKE SURE YOU TIE ALL GROUNDS TO A CENTRAL POINT AND TIE EARTH GROUND TO THE CENTRAL GROUND. ADD FUSES ON THE MAINS SIDE.

Sorry but power takes room
Lesson is don't skimp on the power supplies.

[WookieBoy]

Oh, and to get your +24/0/-24, you should be able take two +24 DC/DC converted lines from the 48v psu, tie the 0v output on one to the +24 output on the other and this will give you a somewhat illogical setup where the 0v/+24 linked becomes your 0v reference. This makes the +24v outpu +24v and the single (not linked) 0v output -24v.

I think.

Again, subject to correction by someone who does electrickery more regularly than me!

[kecked]

ERROR IN HERE: Don't tie the dc ground between the supplies to earth ground. IT has to float as it is not really a ground at all.


24 0------24 0

this is the same as -24 0 24 with the 0------24 being the ground point. Tie this to earth ground as well.

Might have the polarity backward so measure but the important thing is to see how the earth and 0V are tied together. USE vom to make sure what is negative and what is positive.
Make sure to tie the 0V and gnd of all other supplies to this central point as well.
Make sure the earth ground is connected to the mains earth as well. Add a wire even if the supplyes say earth ground.

[sbk]

How about these modular PSU : http://www.vox-power.com/nevoplus600s.html

I have one for the opsl, exceptionnaly small for the power, and you can install 4 different modules so choose your voltages and that's it

[andy_con]

what do you mean install 4???

also am i going to need a loan to buy one of these?

[dsli_jon]

this is where my lack of electronics skills kicks in, 24v +-??? ill need two????

Go here: http://www.photonlexicon.com/wiki/in...ul_Pinout-Maps ..Study this: http://www.photonlexicon.com/forums/...4&d=1363048287 ... and report back to-base in an hour..

EOS, make some really-nice / tiny supplies, as-well.. I'll try and dig-up some refs, later, but, Yes - you want to 'balance your load' on the scanner-side... Not to say you *cannot* use a multi-voltage supply for all your desired-stuff, but, you'll have to find a way to 'share the (overall) load', so the galvos are not 'starved' on one side or another...

cheers..
j