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ArcticMyst Security by Avery

Melles Griot 643 Ar/Kr setup questions.

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So I bought Alex's (Mariomaster) Melles Griot 643 Ar/Kr laser at SELEM and, being the extra cautious person that I am, have a few questions that I would like answered before I fire it up. Alex is evidently too busy to check his PM's, so I'll ask it here.

-For a 220V connection, the PSU's wires color code is, the green wire being ground, and blue & brown wires hot?
-I measured the voltage from the two phases at my house and it is 245V, is that still OK for the PSU?
- How often is it recommended to run a Ar/Kr laser like this? Once every few months?


BTW, This is the box I made for putting the two 120V phases together for the PSU.

fde22b28-18ca-4358-a323-63851b5aba50_zpswkjbjz3j.jpg
 
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your voltage is fine.
maint. burn for 1-2 (min 30 mins) hrs a month. i run mine on full power for about 15 mins, then drop to 1/2 power for 45 mins, then ( if not time restricted) i run it at low power for an hr or so and then shutdown.
 
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I imagine that should be ok, though it may be somewhat hard on the components in the long term. They come in 220/230/240V versions for the 643s but most are 220. The only differences are some of parts have slightly different values and a few other little tidbits. But i've been told they're not the easiest to convert back-and-forth. They should run fine on such a setup. I use a step up transformer. Mainly, id more be in mind the current draw or you may blow breakers or something in your house, which is more likely.
 
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OK, thanks guys.

I ran it last night for about half an hour. Lasing started at 6.5A.
I didn't see the second red line, so I might have to carefully adjust the alignment (just a little) and maybe run it a few more hours.

3478d5cd-f678-46ba-8ee4-2099eec48075_zpswigsq4s0.jpg


cd17ffd6-4b10-43e6-b0ac-d599fb4c0035_zpsptmwokaz.jpg



Picture below, running just at lasing threshold. Just under a kW.

fde22b28-18ca-4358-a323-63851b5aba50_zpswkjbjz3j.jpg
 
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mine lases at all currents, though pretty weakly at the bottom half. how many hours are on it, and how well are you cooling it? mine has over 300 cfm over it! and dont pick it up by the ends or you'll bend up the mirror mounts and have to realign it. if it hasn't been cleaned you may want to do that. I can show you how if you want.
 
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i'd have to agree with Kaiser on the cooling. is that just 2 PC fans that you're using?? if so, that not near enough airflow to cool one of these beasts. mine has a stock fan and on high will heat a 300 sq ft room by 7-10 deg F in an hr or so. really moves a lot of very warm air. make sure that your not leaking air near the fans as well, the tube shroud/cowl is designed to pull air from the ends of the tube, up and out but if air is leaking past the fan/cowl area, that will greatly reduce the amount of air moving around the tube.
and def watch the OC/HR mirror stems, they are very weak and prone to bending. i'm working on building an insulated mirror stem alignment ring set up for mine since these seem to lack any real mirror alignment ability that's stable.
 
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It's just because the frame is a part of the laser, so the alignment changes with how hot it gets. If you pick it up by the ends then the weight of the laser is on the alignment rods. It's not an issue if you pick it up from the sides. They have a pretty narrow bore and are fairly difficult to align. They are aligned generally at/near full power. Cleanliness is essential for these, as any particle in the beam path blocks a lot of light and can get baked on. Mine pushes over 300cfm with a very good deal on thermally and impedance protected papst fans IIRC. It sounds like a jet taking off! After I turn off the supply, the fans stay on for a few minutes to cool the tube before shutting off.
 
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The tube has quite a few hours on it, so it is getting old. I don't remember the exact numbers though.
The fans are 12V at 1.4A and 1.6A. For my test I was slightly under powering them, so next time I run it I'll set it up to run the fans at the full 12 volts.

Thanks for the advice/info.
 
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Yes, I suspect you're pushing 100cfm or so per fan, which should be good up to a bit over a kW. If you're running nearly full power and it's barely hitting a kW then it sounds pretty old. That must mean the operating voltage has dropped significantly, which is a sign of low pressure. It should be probably close to 185V.
 
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At full power it is drawing much more than 1kW, it was at the lasing threshold that it was just under a kW. At max I think it would be close to 2.5kW (I think I saw 10A for a second when I increased the current for brief moment).
I won't be at my house for a few weeks so I won't be able to test it very soon.
 
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