HAR!...
I'm now hearing that the stripping I referenced does increase brightness/removes-wire, but is primarily done for use in commercial-PJ's (and shortens life down to 2k-hours!).
There may be advantages to 'stripping' for varied-other applications -- like focus with reflectors -- but I'd not want to approach 60.-per-2k OR have to add a U/V-heatshield (kills advantages, no?).
Still, if that's a Topspot, it's maybe worth testing as a 'Powerball-killer' -- but not likely any real improvement over a CDM150SA/942, which is cheaper-stateside...

These have a 12.5mm arc-length (see Mavirik's post: http://www.lumenlab.com/forums/index.php?s...358&st=1800 ),
as opposed 6-or-less for CMD150SA/942's...on EBay for 47.
[BTW, now have a source for (cheaper, better?) Topspots...so will review those, later]

Another theory (supported, partially, by elken's and other 90*-findings):
Maybe 45*-placement is used by factories because backlighting has linear-orientation (H-or-V) of backlight-tubes...and 45*, in that-situation, helps with 'light-spread' (and is of no consequence in PJ's)?

hmmmmm,, in answer to silver surfer,, i dont know why this topic was closed,, I reopened it.

that's an improved version of the Powerball.
It uses the "xtreme seal" technology which increases the "pinch temperature" from 350C to 450C
It seems to deal with the max temp, not quite sure.
and the formula's been improved, it lasts 8000H

ok sweeet

well I've read on the first page that ROX is using a stripped CDM :
http://www.lumenlab.com/forums/index.php?s...ilips&st=20

and he says that it's been working for months....he doesn't seem to read his PM though.....

some german guys told me that it wouldn't work for more than a few hours when stripped.......

I've got a CDM in my hand right now, but my SANYO Z3 was sent back for RMA.........so whenever I get it back, I'll give this puppy a try

and if that works, I will order the CDM-SA(short arc) with a 6mm arc instead of 9mm

I tried to strip a Powerball like 3 months ago, but all it gave was a very dim green light.......due to the 130W eballast I would guess...so we'll see how the CDM does on a 135W eballast

quick question, how much do you think these things can be overclocked to? I dont care if the life drops to 3000 hrs or whatever. I don't know the ratios of how the color temp is affected and such, or what point they will blow up or whatever... heh

a 250W ballast will do wonders

ok concerning ROX who says on the first page that he's got the stripped CDM working for several months..........I think he's full of it........

the issue being that the connecting wires of the burner are made of niobium on the ceramic lamps..and this metal start oxidating >200°C:

http://www.lamptech.co.uk/Spec%20Sheets/Ph...%20CDMTD150.htm

http://en.wikipedia.org/wiki/Niobium

regular quartz lamps have molybdenum wires, which oxidates >400°C :
http://www.speclab.com/elements/molybdenum.htm

my stripped powerball after a few hours :


a CDM with a damaged bulb :

Guys, honestly, why are you trying to run these bulbs without an outer envelope? The amount of UV radiation they put off without an outer cover is enormous.

Get over it, stop doing it. Look for improvements elsewhere.

well.......to modify commercial projectors(that have several anti-uv filters) ?

any quartz burner works fine when stripped in my SANYO Z3

there's no improvement possible over a BLV TopSpot...ceramic CANNOT be stripped........ROX is feeding false information obviously

Rox hasn’t been on the forum for some months now.
I think you may have miss-interpreted what he was saying. The electrode connections could vary well corrode when exposed to the air, I don't know. He may have only meant that he had tried it some months earlier, not that he used it constantly in a projector. And if you check his elliptical thread it only looks as though it was in the experimental stage, meaning it was only used for short periods of time.

DJ

well he said "I have been overdriving this lamp at 250W since some months"

ok that could mean he ran it 1h at top within the past few months

and there's some photos :
http://www.lumenlab.com/forums/index.php?s...ilips&st=20

Doesn't he have an email adress he can read ?
I'd love to get some feedback even though it seems that the wires cannot cope with oxygen......

Were you running the CDM bulb with it cracked open? Just wondering, because I have one that the outer case is smashed, and it hasn't oxidized at all. So I'm guessing you were burning the CDM. heh. crazy!

well I have a brand new CDM here, and it seems that the inner connections of the burner oxidize to death >200°C

Did you run your cracked CDM for a long time ?
Does oxygen get into the cracked bulb ?

the wires should turn into white powder..

Oh, I missed the part about the >200c /smackhead

I haven't tried running mine yet. I thought you meant just it being cracked open would oxidize it.

I have a new bulb that I should hopefully get running today. But there is no crack on it (I hope)

well even if it's cracked you could use it.........I'd like to know if it will oxidize

I would think you could flow some solder on the leads to seal then from the air.

It may need something with a higher boiling point: (187 - 238 C)? And be able to bond to the wire.

DJ

edit:
silver solder perhaps (Boiling point=766C for cadmium)

edit2:
Getting it to coat close to the ceramic is going to be a problem

yeah I thought about coating the wires..........but well if Philips/OSRAM didn't do it.....there's gotta be a very good reason

Well, I ran my cracked CDM (to test ballast and such) for about 2 hours, I am not sure how hot it got, but I can tell you that when I touched the tempered glass after turning the bulb off, my skin damn near boiled..

I don't see any Oxidization yet, but I will run it some more tomorrow maybe and let you know if that changes.

Perhaps because of the outer glass envelope, there’s no need to.

DJ

yeah, but they don't use the same metal as in quartz lamps because only niobium can be used with ceramic......

and a coating would have to be razor sharp up to the burner limits

not long enough = air oxydation
too long = might severely screw up with the burner integrity

silver solder still contains other metals that start melting at 300 degrees C

oh well..........the BLV TopSpot is a great lamp......just the red's are pretty bad...........nothing like a good ole' Powerball

This might be too simple. How about flame resistant paint? Some of that stuff can take 1200°C

good point.......I've found some silver HT paint that can take up to 900 degrees Celsius.

that should do the trick, thanks for the direction Mr D.

Hello guys,

You were recently discussing overdriving the CDM at 250w.
Well, i picked up a double ended lamp.
I have skimmed through, and it seems everyone who has done this is happy with the result.

So im wondering
A) where will this bring the color temp (originaly 4200k)

And B )
I will quote the Travelocity gnome from the commercials in asking, "Am I going to die?...."

I just remembered i have a 250w mag ballast in storage.

I haven't done it myself, but HouseMachine is pretty happy with his CDM @250W
burn it for long periods for the first 30H to stabilize the lamp real good

Shweet, thanks.
I will share my experience in here.

I used a standard 500 watt home light dimmer with a M135 ballast and a 175 watt lamp and it worked fine. I see no reason a dimmer would not work with a 250 watt ballast to let you set the power anywhere fron about 100 watts to 240 watts.

I think you guys running ceramics with no outer glass are crazy! but in a good way.

I know one of the reasons is to remove the wire that can cause shadows, but why not just use a double ended ceramic,like the TDM.

Is there a risk of the ceramic lamp putting out a ton more heat with air now being in direct contact with the ceramic.

DRJ

I use MH lamps to modify SANYO projectors myself...Z1/Z2/Z3

Yes, the vacuum within the bulb slows down the heating of the outer bulb.

a naked ceramic gets really hot.......like 650 degrees C

Hiya all, I have a philips 150cdm running right now and I am thinking that my soup ladel reflector is not cutting the mustard (too much vinetting (sp)), is there a SS concave mirror that would be optimal for the small arc size of the CDM's? .....I think the largest they have right now is a 44mm

Also........I keep breaking precondensors (2 so far) is there a tempered glass precon out there?

Thanks

I have a $50 edmund optical concaved FS mirror and it stands my 250w heat very well and works great.

http://www.edmundoptics.com/onlinecatalog/...?productID=1909

I don't remember which focal length I have, but it's 50mm wide.

pnta.com sells borosilicate precons but they're expensive.

Surplusshed.com has 2 to choose from. They're not much bigger that 44m but they're cheap.
http://www.surplusshed.com/pages/item/l3588.html 40mm dia - 35mm fl - 2$
http://www.surplusshed.com/pages/item/l3800.html 45mm dia - 20mm fl - 2$

Here are 2 other reflectors that might work.

http://www.surplusshed.com/pages/item/pm1075.html ELLIPSOIDAL
http://www.surplusshed.com/pages/item/pm1079.html PARABOLIC

Anchor Optics has concave mirrors (AKA radius mirrors) priced from $5 to $15.
Radius Mirrors Link

Tgreenwood

Good find, I thinks that's where I bought mine actually, they just have a goofy name there.

Wow, that is the place to go (assuming they are heat resistant) I couldn't wait and ended up getting a 2 ¼" pyrex aluminized spherical from SS, I have an old low profile copper heatsink that I am going to put underneath the mirror in hopes that it will live ....pyrex is some tough stuff.

Doesn't that have a 9" focal length? That would put it pretty far from the bulb, no?

FWIW, I will be putting two reflectors up for sale in the trading post within a few days. $7 each with shipping. They are all polished aluminum, from 3m and Hanimex OHPs, and are 46 and 48 mm.

Click to view attachmentClick to view attachment

ok so I've tried the stripped CDM on a 135W/1.84A UHP ballast, and it's a bit better than the Powerball.......but still green to death.....and because of the cylindrical burner, I cannot set the arc at the right focal point :



so the "BLV TopSpot" 4200K 150W(know as "USHIO Eurospot" in the US) remains the king of the hill

::::Sigh ::: it looks as though my lack of understanding of focal point has kicked me in the face again, I have been reading the forum for months now but the concept hasn't sunk in.

I assume (now) that the focal point is the point where the light comes to an apex before spreading back out to cover the lcd?

how on earth would you figure out the FL of a store bought ladel?

Well, first I guess we should clarify what we are referring to -- focal point/length or the place we want to place our bulb. The following diagram might help.

Click to view attachment

To quote Hirudin from this post



So unless I'm way off, optimum distance on a spherical reflector will always be the radius of the sphere made by its complete curvature?

And to quote Supraguy from this post, here's how you go about measuring that:

Could it be that your just not supplying enough power to the ceramics? Perhaps the topspot can handle a larger variation in power (heat) so it appears to work better. One thought I had was that the ceramics, when stripped, are running cooler than they should. I know that when I first power up the power ball it appears to be blue/green until it warms up enough. Have you tried to over clock them a little to get them a bit hotter?

DJ

Edit:
Have all your tests been with 135W ballast?

Hi Mr D., thanks for helping

well yeah it's the 135W/1.84A UHP ballast of my SANYO PLV-Z3

The 150W TopSpot gets a bit greenish because it's underpowered, but if I lower the green to -10, I get perfect balance
except for the RED, which is not quite saturated to death "ceramic red"....but whatever....

anyhow, the biggest issue is that I cannot set the CDM at the right focal point because the burner is just TOO BIG.........so whatever...I give up on the ceramic's..........their electrodes oxidize at 200 degrees C, and 135W is not quite enough to warm them up.....

the BLV looks so amazing when properly burned in

I couldn't understand his method so I looked one up and made a picture for anyone else who wanted to know....I am probably duplicating someone elses work but..oh well. The numbers I picked below were from a random circle I drew and not of an actual part, the formula works for any size sphere.

EDIT: I have updated and double checked the formula.

I am mathematically challenged, so forgive me if I missed something, but in your simplified equation d is over .5 and when you plug the numbers in, d is over 2. I am guessing 2 is correct?

Soo sorry for the bad math, I was trying to crank this out at work and wanted to get it done before anyone came looking over my shoulder.

Okay, I know it's the 150W thread, but while I was checking on Philips' web site, I ran across this:
320W CDM/942

It has a longer life (20k to 12k), and obviously more lumens (~29k to ~13k) but at a slightly lower CRI (90 to 96).

The kick is, they don't actually seem to be available anywhere yet. I was going to send them an email and ask if it's something new and if so when it's going to be available. (and what the arc length is)

Anyways, I was curious what people thought as far as a CRI or 90 vs 96. Is that something that's going to make a big difference? I would think the larger amount of light might be worth the heat/CRI tradeoffs if the arc length is the same as the 150W CDM people are looking at at least in my case.

Well, I'm not sure about the 320 watt one, but look at the picture they are showing..



Seems like the arc has troublesome wire all around it.. And the bulb itself looks to be easily 2-3x as big as the 150w.

Instead of that bulb, the Eye Cera Arc 400W might be a better option. 90 cri also, smaller T17 shape and no wire issues, though I doubt it would cause any problems on that one. It also seems like you'd have to use a fairly large reflector to get the correct fl.