Building a short arc searclight

Have not heard anything about arc chamber shape should have any effect. As far as I know, the key to throw will always be luminance. The higher the better. And short(er) arc usually give you that. The MSR SA lamp (slightly dimmer) will out throw the regular MSR lamp. Different brands have different names for instance Osram HTI 705W/SE, Philips MSR 700 SA and Jenbo NSK700SA are all the “same” lamp with more or less the same specs. The only thing about the arc chamber I would think about, is that some lamps, (all of these) has the fill knob right over the arc. It will give you a slight artifact in the beam. But I have been running the MSR 400 watt SA lamp now, and I can’t say it bothers me at all. The other day I reached 6500 meters/4 mile with only a 7.9” reflector. That’s a decent result, artifact or not :wink:

To bad about your xenon plans :frowning: Didn’t you look into the 300 watt single ended lamp?

This is the thread I was referring too. http://www.candlepowerforums.com/vb/showthread.php?145887-Anybody-change-a-Maxabeam-s-lamp

I didn't look into the single ended short arc lamp. Overall though the effciency of xenon short arc is too low. Most of the regular 300watt short arc bulbs are only 7000 or fewer lumens. My FF4 can output that many lumens lol. I'm looking for something in the +13k lumens range and that'll require atleast 500watts or more in xenon short arc bulbs. I could find some 500 watt ballast but they were all 220volts AC which won't work over here.

Also there are no XSA bulbs t range that could be run in a horizontal orientation. I either had to go well below or well above 300 watts to get a bulb that could, and here again I run into the issue of them being too dim below 300watts, or too big and bulky and using 220volts above 300watts.

Anyway I've ditched xenon short arc and am looking into other means of achieving my goal. HMI, UHP, and MSR lamps all look like viable options that'll be much simpler and easier to deal with. I've emailed a few companies and am waiting to get word back from them before I make a decision on what bulb type I'm going to use.

I would like a light that has extremely long throw but at the same time I would love to have the maximum output possible too. HMI lamps have the highest overall lumens output but they are not short arc bulbs. More like medium arc length. Plenty of ballast options for HMI exist in the 500-1500 watt range and on the upper end of that range we are looking at 110k lumens output. Even if I didnt have the tightest beam out there the sheer output is extremely high. With such a deep reflector as mine I think the throw will still easily beat something like the maxabeam while being much more floody. Maybe I can strike a balance between a super thrower and super high output and still get super impressive results!

If I can get the ballast I want they can power a variety of bulb types (HMI and MSR lamps included) so maybe I can play around with different bulb types to see which ones work best for me. The MSR lamps are not quite as efficient as the HMI but they are true short arc bulbs with very high luminance intensity. In my reflector they would make a killer thrower especially the 850 watt bulbs with a 3mm arc length and 56k lumens output but the problem with them is the CRI is rather low and the CCTs are quite high at ~7500k. Not unusable but still not as great as the 5600-6000k found in XSA and HMI bulbs.

Ahh decisions decisions lol. If I get the ballast I want I'll likely end up with both the HMI and MSR, and UHP bulbs and test all three to see which one produces the superior beam.

Now that was a very interesting read about the arc chamber! Have never thought of that, then again, that maxabeam lamp is also the first short arc lamp I have ever seen with a tubular arc chamber :~ Now some of the metal halide does have it, but for the most part only the longer arcs. And then you of course have a lot of lamps with an extra tubular protective bulb. I guess you should steer away from them if you need that extra candlepower.

Yeah, join the club :bigsmile:

Exactly. That ruled out the HMI bulbs as all of them have the outer protective tube around the inner globular arc chamber.

Yeah LOL! Fortunantly I think I have narrowed it down to two ballast and two bulbs. My first choice is the Osram Lok-it! 1000 paired with the Elettrolab EDB1000 ballast. 85000 bulb lumens with a 5.5mm arc gap should produce some astounding results!! My second choice is the Osram HTI 705 paired with the Rotec ECG 800 ballast (Polari didn't you use this ballast in your vintage light with the MSR bulb? Super nice light BTW). Being that both ballast MFG's are overseas payment seems to be an issue especially for the Rotec. And Elettrolab does not sell directly to the public..sigh..Still got to work their salesman to see what I can get out of them.

Once I determine which ballast I can get then I'll know which bulb I can use. After I get the bulb I can resume building the light as I have done about all I can without actually having the bulb in hand. Deciding to go with a single ended bulb certainly made the build a whole lot easier. No troublesome returns wires or cumbersome mounts to deal with as supporting the bulb end near the glass widow would prove to be a HUGE pain LOL!

85.000 lm over 5.5 mm give you 15454 average lm pr mm… You won’t get that Xenon cathode peak, but it will be a killer light no matter what. You will get some spill, but also a massive throw! :party:

I know all about hunting for a ballast. (BTW, yes, I have both the 800 AC and DC from Rotec) So if you don’t get that 1000 W, I do have a suggestion for you. Since we are in overkill territory anyway, why not go for 1200 watt? Philips has a lamp called MSR gold 1200 SA/SE. 93.000 lumens, 5.5 mm arc length…
And here is a ballast: http://www.ebay.com/itm/Mac-2000-Electronic-E-Ballast-1200W-part-06100011-/291299571267
Note, you still need an ignitor for electronic ballast.

The lamp: http://www.usa.lighting.philips.com/main/prof/professional-lamps/special-lamps/entertainment/touring-stage/msr-short-arc/928174605114_NA/product
One more thing, and that goes for any lamp. Make sure you have enough clearance where the lamp pass the vertex hole. Running 4-5 kV cold start ignition, you also need 4-5 mm clearance from the return wire to avoid an arc over.
PS, you need a glass lens running this much power, tempered or boro plus good cooling. Not only the lamp, but also the reflector as the aluminium coating doesn’t like to much heat.
EDIT: Max temp for the reflector coating is 250 F. I sent you a PM.

The automotive HID bulb I used has a 4.2mm arc length. So Ill to get a slightly wider beam with this bulb than with it.

Okay Okay. I was originally going with a 300 watt XSA, then I bumped up to 500, then back to 300, then up to the 700watt HMI, and now I'm at a 1k watt HTI. And you now you're trying to talk me into 1200watts! By the time the light is complete Ill be at 20kw!!! LOL JK

Any way that is a good suggestion! I had wanted to go with the Elettrolab EDB1500 watt ballast and the Osram Lok-it 1400ps. 120000 lumens with a 4.5mm arc length, but the 1500 watt ballast is 220 input so thats why I dropped back down to the 1000 watt. That ballast you linked to though has 105-264 voltage range so I will definitely keep it in mind! Thanks!

The vertex hole on my reflector is 35mm. The Lok-it 1000 has a 21mm arc chamber width plus probably 2-4 more mm for the return wire. Thats gonna put it right at 4-5 mm away from the edge of the hole.......lets hope it doesn't arc. Otherwise I may have to find some high temp electrical insulation to prevent that. Wouldn't electrically insulating the ballast from the rest of the housing prevent the bulb from arcing though? If so I could just mount the ballast on some rubber pads to insulate it from the housing.

Regarding the arc, there is another important factor at play here, and that is arc width. The arc will be much wider on that 1-1.2 kW lamp compared to the tiny car HID, so a big part of the arc will be out of focus, meaning more spill. But either way, the throw will still be colossal, don’t worry about that!

As for HV, I’m no electrical engineer, I just like to make things… The 4-5 mm distance is the normal rule of thumb for a cold start system. When it comes down to the HV stuff and my lack of knowledge about that, I prefer a little bit extra insulation and/or distance, and never have to worry about any issues. I prefer it that way :wink: As for the vertex clearance, you can always cut/file a small groove or use some extra insulation if you not comfortable with the way it looks.

As with the maxabeam, proper searchlight reflectors are optimized to work with a specific light source and dont mix and match very well. All applied theory aside, its going to be hit and miss trying to find out which ones provide the best results and culminate a narrow beam, unless someone has already blazed the trail for you. Your reflector might not be suitable in creating a narrow beam HID searchlight. The money to find out could buy a VS3 (I linked above), which provides a ruggedized, fully engineered solution with high tech guaranteed results, and with a timelessly high resale value. However, you’d still need a way of powering it.

Whatever path you take, I wish you the best of luck.

Okay so for 2 week I have been getting the run-around on the ballast. They sent me the pricing and all and I told them the address to ship to and what all I needed. They told me they would get back with me with a shipping quote and 2 days have gone by and still no word from them. Can't call them because they in another country plus I cant speak Italian Hopefully Ill get something from them soon.

Anyway I got one of my cooling fans in. 12volts brushless 92mm 175cfm! This fan is a serious powerhouse but its super noisy! Now I have to buy a 120->12volt voltage converter to power the fan. Also have to built a regulator for the fan as I doubt the bulb will generate enough heat to require this fan to run at full power continuously.

My current idea of cooling is having this fan at the rear of the housing blowing compressed air into the housing and circulating it around.(Mind you the housing is very small for a fan that blows this much air) There will be a smaller fan right near the bulb to remove hot air. If that does not work sufficiently I may have to reverse the order. The small fan next to the bulb blowing air in around the bulb while the big fan in the rear blows the hot air out. Can't do much testing with airflow yet as I can't complete the housing without have the bulb socket though.

Im also having a tough time finding someone who has the bulb socket in stock. Bulbtronics should be getting back with me soon but the representative told me something I didn't understand over the phone. Something about them having not sold any of the bulb sockets since 2014 and them having to bid on them to get a price....I have no clue what he meant. Either way the most difficult part of this build so far has been simply sourcing the parts. If I could just get a hold of the parts I could have had this build finished by now LOL!

No this project is not dead LOL!!!

So after nearly 3 weeks of back and forth emails with the manufacturer and their dealer I have finally gotten everything finalized for purchasing the ballast and quite a few accessories for it. Problem is I got hit with a massive $167 VAT tax and that has me temporarily held up on actually placing the order. Anybody know if there is a way to get this tax refunded for internet purchases?

My understanding of VAT is that a company can void it if the goods are being shipped outside the EU since the VAT is specific to “end-users” within the EU only. I’ve had companies waive the VAT when shipping to me and only a few times has the vendor refused to take it off. I would politely ask that they not charge the tax and see if they honor it.

I asked the distributor about it and was told that only businesses were exempt from the tax. Everyone else has to pay it. Seems to be different from everything I've read online.

That’s partly true, but like most things tax wise there’s always more to it.

Anyway it’s sounds like they either don’t know the rules or more likely couldn’t be arsed as it evolves form filing on his or her end.

If you were in the EU and you bought it in person, you would pay the tax, then when you got to the airport you would go to the tax desk ( it’s probably called something else) fill in a form make a declaration that your a returning to the US with your purchase, show your passport, airline ticket etc, they then refund you the tax/vat

As you bought it over the phone/Internet, and the seller shipped it to the US, the seller should have simply not charged you the tax/vat on the item, and filled in a form stating as much and sent it to the relevant tax authority

That’s my understanding of how it should work

The seller is probably confusing the rules differentiating between charging VAT for “goods” vs charging VAT for “services.”

General consumers in the US can be charged VAT for services provided by UK based merchants if they meet certain criteria, but goods are not subject to VAT.

I think they probably don’t want to do the small amount of extra paperwork that’s required when VAT is exempt. the good news is that you (consumer) can file a claim to recoup the collected VAT. I don’t know how long that takes before you’re reimbursed, but I imagine it’s a streamlined process by now.

I have not placed the order just yet. I emailed the Italian consulate in Miami FL and am going to see what they say about getting the VAT returned before I place my order. Im sure that if I can get it returned they will also have all the required forms that need to be submitted to do so.

Thanks so much for yalls help! Eager to get this light finished.

So the consulate told me that VAT is only refundable if you shop in Italy. VAT is non-refundable for online orders.

Ballast and bulb have been ordered!! Also bought the OEM cooling fan, the 4 segment display, and both hot and cold restrike ignitors so that I can run multiple different bulbs from the same ballast. Ballast has a variable output from 381watts to 1000watts so if for whatever reason I have problems with the 1000 bulb running too hot for my reflector I can scale back to something with a more manageable heat output.

After 3 months of back and forth discussion with the MFG and having them accidently ship the ballast to the wrong country and getting all the problems corrected the ballast finally arrived. After all its escapades it arrived in pristine condition! Lamp should arrive soon too but sourcing the lamp holder is still a problem. I may be able to power it up without the lamp holder though. To be continued....

Goodies. Yum..

Intense! :slight_smile: Short-Arcs can sheer out some real KCDs, and in a reflector of that size i can see it shoving a beam well past a mile.