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I was thinking of using 2 prong instead of 3 prong 110V cord/ plug on my next projector build-- any biggie? Any legalities?
(I know why there's a ground- If anything shorts to gnd it may make the chassis hot)
Does everybody run grounded projector cases? -or not..
(We 'float' our 'scopes at work for a reason..;) ) - I know, unrelated..
Just curious:) .. how many run grounds and how many not..
When dealing with things mounted to metal I think it makes sense to use a ground.
Yeah, I grounded mine. Best management practices and all that. I think you ought to ground yours as well Steve. It *is* a safety concern. Besides, if you ever sell it, people are going to expect it to be grounded.
Why are you thinking about not grounding it?
Adam
Over here in the UK, all electrical appliances must be earthed or double insulated, I would tink it would be difficult to double insulate a projector.
Jim
I just have a good long length of 2 conductor high quality heater -type cord. Nice and flexible and sturdy. If the input transformers were double insulated from the chassis, everything else is low voltage (unless 120V fans and interlock switches etc are used..)
I'll probably ground it anyway.
I was also thinking about gnd loops and noise issues in case of a building gnd fault. I usually dont carry a GFCI around:)
Steve, I can get you one of the sockets and the wire (its somewhere between 10 and 20 feet) to go with it like the one on this auction, it will take 40amps of 110. Free of charge, just pay shipping
http://cgi.ebay.com/ws/eBayISAPI.dll...m=330191500994
Hello,
The one I have built is also grounded:
http://www.technoroam.sk/lasershow/d.../P1_WIRING.PDF
Greetings
pishtak
www.technoroam.sk/lasershow
Thanks Dream Beamz, I do have 3 conductor cable, I was just wondering if everybody grounds their case.
look closely, that is not the normal cable you are thinking about. The plug I am referring to is meant for 20amps of 220vac but I use for 40amps of 110 when neededQuote:
Originally Posted by steve-o
I'm not running a gas laser here, just a small 1/2 watt diode/dpss so a couple of amps @120V thru the cord should give me plenty of current to work with after the transformer/ psu coverts it to lower voltage/ higher current.
BTW- I looked around the house to see the appliances that run 2-wire ungrounded and there was the stereo receiver, dvd burner, vcr, a box fan, george foreman grill and several other things I dont have time to list right now..
Right, but I thought your concern was the sturdiness of wire. The plug and accompaning wire would take care of that for you. Anyhow.Quote:
Originally Posted by steve-o
Your electronic equipment is not a stereo, vcr or anything else you just listed. It is a highly sensitive laser and must be grounded unless you are using it in a test environment for a short period of time. Please, take everyones advice here, ground it
I just like the "feel" of the wire I have.
Yes I know that grounding is usually the best practice (I've been working in electronics for 33 years , I have a degree in electronics, and work with industrial Delta 230/ 480 VAC) However, grounding is not always necessary, and sometimes hazardous under certain conditions. I've seen 2 pieces of "grounded" equipment at very different and hazardous potentials. It depends on the quality of the facility wiring, maintenance on that wiring and the equipment used. Also, I know that a vcr is not the same thing as a laser projector:rolleyes: but the point is some do not have to be grounded because all of the high voltage circuitry is isolated/ insulated from the chassis and there is only low voltage is present exposed inside the metal enclosure; therfore no risk of shock, and sometimes even safer, depending on the circumstances. Not all people know what they're doing concerning electrical constuction.;)
With your experience and qualifications you should know the reasons why grounding is used.Quote:
Originally Posted by steve-o
You should also know that items that are class 2 (double insulated) are not just boxes without the earth connected.
Jim
Yes, I know this.. Oh nevermind, forget this thread..
Go over to 'joke a day' It made my day:)
For some reason I cant let this go..
OK -I could draw a picture but I aint gonna..
Picture 4 "wall -warts" in an enclosure powering 3 lasers and the scanners.
No High voltage except the120/240 vac entrance which is heavily insulated/ isolated with big thick cord and FOUR layers of heatshrink and electrical tape hi-potted to 20KV. The 'on' key-switch is a 4PST low voltage relay. Got the picture? Why would we want to ground this enclosure?>:) Arrrgggghhhh!!!:eek:
Steve, I may be off base, but did you see my projector at SELEM? I had a power strip that I plugged into a wall and had a wall wart(maxyz), two plugs (1/blue dpss, 2/green dpss), plug for the scanners, and one for a psu for a couple of fans.
spec and DZ rewired it to a nice bus bar to hook up to a plug on the back of the projector, which had a ground. I wanted them to do it so I could get rid of the wall warts and extra plugs AND the power strip. The bus bar acts as a power strip and is grounded. To me it looks a lot better inside and I guess it is safer for the delicasees in there... ;)
But ride on man and take some pictures when you are done. http://photonlexicon.com/forums/images/icons/icon14.gif
Sorry I'm drilling this topic into the ground..:rolleyes:
I'll let it go now, thanks for all the good advice, y'all:)
When the laser has been sitting in the garage for a week at 10 Celsius then you take it into your nice warm living room at 24 Celsius all of the metal is going to get condensation on it, I wouldn't want that to be without an earth would you?Quote:
Originally Posted by steve-o
I know you can say that you would never do that, you will always keep the laser at room temp etc... , accidents happen too, you may knock a drink over near the projector....
See where I am coming from?
Jim
.................................................. .......................Quote:
ha ha ha, ha ha, ha ha ha, ha ha
Well, I showed up at SELEM with my ungrounded argon, my ungrounded projector and my ungrounded TEA arclamp which I gave to Steve.. say, has anybody heard from MixedGas lately?;)
I guess I wont be getting my ungrounded self invited to the next Selem I suppose -heh-...:p
Steve, you know better than that. You're invited to SELEM whether or not you ground your kit!:D
As for grounding the arc lamp - well, that's pretty pointless, don'tcha think? The thing was already dangerous as hell!:p
Actually, grounding it wouldn't do a whole lot to make it safer. (There wasn't even a metal case to tie the ground to...) Still, it was cool to watch that thing - even if it was a nasty source of UV. Wonder what Steve Roberts has been doing with it? (Vaporizing samples of hair tonic maybe?)
As for the issue of grounding a projector... The safety issues aren't really the primary driver here. Yes, you can safely insulate your projector against any of the 110 getting to the case. I think the real reason people are harping on the grounding issue is that you want that ground to provide a solid signal ground for your lasers (specifically the blanking circuit) as well as for your scanners, and since those devices are all located inside your projector you need the ground there.
Yeah, you could isolate the whole projector and then rely on the signal ground on the ILDA cable to be a good ground. But I'd rather have a big, fat copper wire grounding everything in the box instead of relying on a strand of # 28 wire in the ILDA cable. But hey - that's just me! :D
If you are worried about ground-loop issues and are thinking of lifting a ground to eliminate the loop, I think it would be preferable to lift the ground on the host PC that is talking to your DAC.
But yeah, this thread did get a little out of control. Some people are pretty passionate about safety I guess. And to be fair, it's a bit more of an issue in Europe with their 220V mains... Still, you *can* run some electronics without grounding the chassis. I just don't think it's a good idea here.
Adam
PS: I didn't notice that your argon was un-grounded at SELEM. That *is* risky... An ion laser is a completely different animal from a VCR or a George Foreman Grill (or a laser projector even). Between the several amps of DC flowing in the head and the multi-kilovolt starting pulse, I know I'd prefer to have the case grounded in case something went wrong.
Oh, 'Shielding' against noise (electronic) and 'Ground' as in electrical safety - osha, UL , CE etc.. I see... Thanks Adam, I just dont think I'm a safe kinda guy (although I would never put anybody else at risk--If you noticed at SELEM, I guarded my table pretty well..) unless I wasnt there..
and left my lasers running... well....
Just got yout PS-
-edit- I use a spst momentary contact switch and a 'bug zapper' xfmr for the igniter ckt on that argon and the KV is only present while my finger is on the (insulated) switch. It cannot come on accidentally as with auto-start circuitry on normal ar psu's.:)
Ha-LOL:D Steve, what are you doing with that thing?:DSomething fun I hope!Quote:
(Vaporizing samples of hair tonic maybe?)
Adam, As far as analog and digital noise issues go, 2 separate grounds are recommended for each , and a single termination point is best for each one.
I didn't even think about the ground on the ILDA, putting safety to one side, if you had a fault just think of the cost of repairing your DAC and PC.
Jim