Projector Power Supplies

so looking to build a compact projector, but one big issue is the amount and size of switching mode power supplies.

dt scanners come with a big 24 v power supply and modules come with a big power supply.

there must be someone in the power that makes good quality small(ish) power supplies that i could use?

the next question is how to run scanners and modules off a single power supply in order to save space.

galvos run on 24v, a OEM 1w LW green runs on 5v @ 8amps (i think) and 12v @ not sure how many amps. you can buy a big 24v 15 amp PSU but its massive, but does have potential to run everything.

all good suggestions welcome

Hi Andy,

Here is a start.

These are supplies I bought for a mini projector.
http://uk.farnell.com/xp-power/ecs25...cal/dp/1821521

They are 24v each not +- 24v so you need to use two.

The pics below show how small they are compared to the supply that comes with the DT40s

These supplies are rated at 25Watts each making 50watts. The original is rated at 35watts so they have enough power and then some.

+-24v supplies aren't that common and something like above is probably the go.

As for the 5v and 12 v. It's quiet possible you will find a single switch mode that has 5 and 12 v together.

RS and Farnell are a bit pricey but they make it easy to find what you need and have quick free shipping.

I went with XP Power on Dave's recommendation a while ago. They are nice quality and do have some quiet compact units and are reasonably priced.

You could buy cheaper but after doing quiet a lot of searching I found then to be a good balance of price quality and six.

Good luck
Kit:)

P.S. I've got 3d models of these too but same problem as before. Have a chat to Dan about which software to look at where you can use solid models. I will make life a lot easier for handling models for your CNC too. IGES and STEP are the most universal format for machining parts.


Attachment 38322Attachment 38323

this is where my lack of electronics skills kicks in, 24v +-??? ill need two????
by the time i have two it will be the same size as the original psu


a LW OEM green comes with a combined 5v/12v psu but its big.

it would be nice to run the green off the scanner psu, thats why i was looking at something like this

http://www.ebay.co.uk/itm/LED-Lights...item232b44ffc3

but its bloody massive, it has 24v + and -, i think???


on the CAD thing i drew the dt scanners last night only took 10mins so all good cheers

Yeah I'm in the I know enough to be dangerous category with my electrical/electronic knowledge too :o

That supply on the ebay link has the same problem. It's only 24volts +

I'm probably one of the least qualified to explain this but I'll have as go.

If a scanner is sitting still and the beam is pointing straight ahead the input signal from the scanner amp will be 0v.

If you ask it to scan all the way to the left, it will require up to 24v+.

When you want to scan all the way to the right, the amp needs to supply 24v-

That's why you need two.

Even with the two of those little 24v XP Power supplies, they take up less than a third of the volume. so you are till ahead.

i see thats a shitter, i didnt know that. i assuming when a psu reads 24v+ and then 24v- its all good but maybe not.

so really the scanners need a dedicated psu, thats another shitter as it rules out using one psu for the whole projector

this size would be good for all psu ;-)

http://www.aliexpress.com/item/25W-1...628326824.html

Yeah pretty much.

If you get the naked versions without their casings they can be pretty small. You just need to make sure that the have the proper clearance for cooling and insulation to keep the 240v ac from biting you.

Don't get disheartened. when you actually see some of these supplies in your hand they are tiny.

If you can post up a list of the voltage and current draw including the ones your not sure of yet, we can suggest a few models that will give the right combination in the most compact size.

One plus side to having multiple supplies is that you can tuck them in little spots that a larger one couldn't go.

well dt scanners so 24v

and LW 1w OEM just waiting for rob to confirm psu spec but i know its 5v and 12v

what about these, they seem any good from the spec? they are nice and small

http://www.micropowerdirect.com/Page...0ACDC%201.html

what would be good would be to put a big psu that outputs say 48v at 20amps and then use dc-dc convertors for scanners and module

That's how RGB lasersystems design their powersupplies

what one big one then dc/dc convertors?

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 :p

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

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... :confused:
Please someone with less cobwebs in their brain, chime in and correct me if I'm wrong on any aspect of the above! *retardo

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... :)

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.

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! ;)

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.


Attachment 3833124 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.

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 :)

what do you mean install 4???

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

Quote:

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Originally Posted by andy_con

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

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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... :cool:

cheers..
j

http://www.mpja.com/24-Volt-Power-Su...fo/16032%20PS/

Quote:

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Originally Posted by andy_con

what do you mean install 4???

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

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You have the framework and then you can install up to 4 modules inside the framework, with a choice of different voltages and power.

I don't know the price as I received it with the laser but I just had a look and I'm afraid it should cost >400$ for a complete unit with 4 modules... But that's the must, it's worth the price if you have a serious projector to power.

Have a look here : http://components.arrow.com/part/det...1S9090830N4190

i only need 2 not 4 so we will see

Quote:

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Originally Posted by sbk

You have the framework and then you can install up to 4 modules inside the framework, with a choice of different voltages and power.

I don't know the price as I received it with the laser but I just had a look and I'm afraid it should cost >400$ for a complete unit with 4 modules... But that's the must, it's worth the price if you have a serious projector to power.

Have a look here : http://components.arrow.com/part/det...1S9090830N4190

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surely if my starting psu, say i go with a 48v has enough juice to power everything and more. then the scanners can pull what they want and it wont cause any issues?

cheap - good - small

pick 2

I never said cheap I just don't want to have to take a loan out to buy one

My green 500mw just takes 5V at about 6A (iirc) to power it. I'm going to run all the lasers off of one 5V rail. The only other thing I'm unsure of is the galvo psu. Probably have to be a separate one + 24V. I'm bulding a whitelight RGB "notebook" (slim style) projector (hopefully.) The 5V supply is just going to be an old fashioned (non-switching) transformer-bridge rectifier-capacitor-linear regulator type. It should supply about 20Amps and not be too big.
Your 532 requires both 5V and a separate 12V? Maybe just get a buck-boost converter (really small lil things) to convert the 5V to 12V if the current draw isn't too much .

been confirmed by rob only 5v

you should setup as I drew the +/-24V supply for the scanners and use a separate one for the lasers. 5V 6A switchers are cheap and everywhere. Use it. Not sure why its asking for 12v? Maybe to run a fan or TEC? I bet you need 2-5A if its a TEC so then use a third supply. Again tie all grounds to a central point and earth.

I was just looking to see about making a design for the forum but its not worth the effort. What you see on the market is fine. To save space I stack my supplies on top of each other. Makes a taller box but smaller foot print.

If you are making a small laser it is usually small power so then you can start looking at using the scanner supplies and dc-dc convertors. If you draw a full amp off a rail you'll unbalnce the supply. Don't forgret the Vf on the new greens is 8.6V! So you need 250ma at 12V for that driver, 6V for the blues, and 5V is plenty for the reds. So a 12v 3amp supply with a 5V 1amp output might get you there if the blue runs on 5V (most do). That's a plain jane computer power supply.

Are you suggesting an additional 5v supply vs using 12v for all diodes because of heat dissipation?

That vox power block is pretty cool!

Quote:

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Originally Posted by kecked

Attachment 3833124 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.

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... Umm wouldn't the 24VDC on that power supply on the right see a direct short to ground in this setup? I was thinking of something like this as well but I don't think it is possible with two independent supplies. Seems to me we would need a center tap transformer, where the center tap would be 0VDC bonded to ground .... Then rectify, regulate, and filter the +/- as required.

I hope I'm wrong, because it would be really nice to use independent inexpensive supplies to get the positive and negative rail.

Yes I was wrong and it made a hell of a problem for me. You can put the supplies in series as stated but not tie the center of the supplies to earth ground. It will make your life hell. Let it float. Works just fine that way. You just rely on the ac side earth ground on the supply cage for safety. The dc side is not an issue. You could most likely put your tongue on it.

As I know some one uses one single PSU to produce high DC voltage (far higher than 48V) then DC-DC them down to many outs.

PSU is truly painful when building a compact projector.

There are high power module type PSU but cost alot! and requires good heatsink to the base and some little external component

here are some examples :
http://www.vicorpower.com/

http://www.tdk-lambda.com/products/sps/ps_pm/bodye.html

http://www.cosel.co.jp/en/products/sub04-13.html