Running a laser off a generator

[Joe Hillmann]

I want to run my laser at craft shows and flee markets, the problem is several of the largest ones don't have spots with power available, I had planned on using deep cycle batteries and a true sinewave inverter but cost and weight made me realize that wasn't the way to go. So now I am looking at generators.

This is the generator I am looking at http://www.costco.ca/Browse/Product.aspx?Prodid=10338741&lang=en-CA

It gets good reviews, but my concern is, is the power clean enough to safely run a laser. I sent an email to the manufacture asking for a graph of the waveform under a 1000watt load. I just sent the email yesterday so I haven't heard back from them yet but well searching online I came across these sites that show the output of the generator.

This one looks nice and cleanhttp://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24022161/gotomsg/24923563.cfm

But this one(same model) is very jagged but still follows the wave much better than a modified or square sinewave inverter http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/15131645/srt/pa/pging/1/page/868.cfm


So what do you guys think, would it be safe to run a laser on one of these generators? Also if I do buy the generator I plan to find someone nearby with an oscilloscope to check the output of the unit I get just to make sure there is nothing wrong with it.

[Gary Hair]

Joe,
I don't think you'll need 1,000 watts to run your laser, multiply the amps by 110 to get the watts, my bet is it is less than 400 watts. Given that, you could use a UPS to clean the power and it would be a lot less expensive than your original plan.

Gary

[Joe Hillmann]

The laser tops out at just under 300 watts when restoring at 100 power. But then the computer is another 140 watts and I haven't tested the exhaust yet but I would guess 400 watts at start up and 200 when running. All that adds up to nearly 700 watts. Then add to that if I need to refill my 40gallon compressor 4 or five times a day. I had planned on going with batteries and an inverter or a ups but when I ran the numbers it was to expensive. Just having the tower of the computer running would take 70amp hours per day and I plan to be out a minimum of 2 days at a time and some weeks I would like to be out for 6 days. Then add to all that the extra weight of batteries I decided the generator is the way to go (if the power is clean) since it will cost around 560 by the time I pay tax and a costco memership. It is also only 53 db so if I have a 25 foot cord and put the generator in the woods behind my spot it should be nearly silent especially in comparison to the exhaust blower and laser.


Edit: Also one reason I wanted to go with batteries originally is because one of the best shows (once a year, compared to many of the others that are every week) doesn't allow generators, no exceptions. So that just means at that show I will have to sign up early enough to get a spot with electric and pay the extra fee.

[Glen Monaghan]

You can't do much about the laser but 140W for the computer is pretty high. Sounds like you are using a regular full-sized desktop type computer when you should be running a laptop. A 45W laptop will work well (that's what I have), is much easier to transport, setup, and tear down, and only sucks a third as much power. You probably could do better on the exhaust as well.

Then figure out whether you really need to run the compressor for air assist. I've just always used air when cutting BB and had to clean up the resultant dark stains along the cuts. Until recently, that is, when I forgot to turn on the air and didn't realize it until I was all done and went to shut off the air supply, only to discover I'd never turned it on. The wood was almost perfectly clean! After some experimentation, I'd say that the air assist blowing at the cut was forcing the resinous smoke down onto the wood where much of it condensed and stuck. Without air assist, the exhaust pulls the smoke away without giving it a chance to cool/collect. No more air for BB!

-Glen

[Joe Hillmann]

Glen,

You are right, a lap top would require less power and I considered it but then I have to buy a laptop which adds to the cost, and for an exhaust blower, when I was looking at the battery route I was going to go with a 12 heater blower from an old truck. But going with the battery route the cheapest 1000W pure sinewave inverter is $200. Plus deep cycle batteries are about about $1 per amp hour so that is another $200 if I can find a place to recharge them at night. Then the weight of the batteries needs to be considered. When it comes down to it either way it is going to cost me about $600 but with batteries it I will always be very limited on how much I can run the laser whereas with the generator I won't have to worry. Plus, if I buy a generator I have a generator for camping and back up power in case of a poweroutage.

As far as air assist, I use it when cutting through but what ever I am cutting must have airflow above and below it to cut clean. If I lay the item I am cutting on the table and use air assist then I get the smoke stuck to it, also if I am rastoring and have the air assist turned on it blows the smoke down onto the item and causes it to stick much more than it does without the air assist.

[Gary Hair]

Joe,
I'm not suggesting you get a ups with enough capacity to run your equipment, just get one that will clean the power. The better ones run the equipment off the battery and use ac to keep the batteries charged. If you are drawing more current than the batteries hold then you are just using it to clean the power.

Gary

[Joe Hillmann]

Ah, I see, I will have to look into that.

[John Noell]

Joe,
I'm not suggesting you get a ups with enough capacity to run your equipment, just get one that will clean the power. The better ones run the equipment off the battery and use ac to keep the batteries charged. If you are drawing more current than the batteries hold then you are just using it to clean the power.

GaryAfter lookng into the ability of UPSs to clean power, I chose to go with a voltage regulator (APC Line-R). I was told that the laser power supplies are more sensitive to voltages than the shape of the waveform. I do see that the newer APC UPSs have added much better voltage regulation however. I am on 230VAC and the tightest I can set my UPS is to cut in at 196V and clamp at 256V.

[Matt Turner (physics)]

. . . the laser power supplies are more sensitive to voltages than the shape of the waveform. . . .

This makes sense. I think the laser is just running off of AC/DC convertors, so you need to be worrying about protecting against spikes and surges and not whether it's a clean sine wave.

[Darren Hollinrake]

Instead of an UPS to condition the power, you could use something called a line conditioner. Basically it's an UPS without the battery and would help keep your total weight down. APC and Tripp lite make them along with many others I'm sure.

As far as using the generator to power the laser and everything else, I'm not too sure. I can tell you I've ran all sorts of sensitive electronics off generators (both large and small 2.2KW-80KW+) and never noticed a significant difference in failure rates between the the ones we had plugged into the UPS vs directly to the generator.

[Jerome Stanek]

I would look at one of the Honda generators they are a lot quiter then the others but that comes with a bigger price tag. It is hard to do business with a loud generator running behind you.

[Rich Harman]

The Honda Super Quiet 2000W generator claims a noise level of 53 to 59 dB while the Costco one claims 53 to 61 dB. If those claims are accurate, either one is going to be very quiet running.

[Joe Pelonio]

Before you make further investments, have you talked to them about the exhaust fumes? I can't imagine any of the flea market/craft fairs indoors or out allowing that without a really good scrubber system which would require even more power.

[Steven Cox]

I've been running a mobile set up for over two years, and don't have any issues running from batteries through an inverter. We have 6 x 6 Volt 225 amp batteries connected to give 675amp at 12 volt. This gives us enough power for a full day of heavy use. We have run direct of a 2.5Kva pure signwave generator again without issue but I prefer to run from the batteries and if needed just use the generator to charge the batteries. Bear in mind our battery system alone weighs over 200 kilos but its all permanently mounted in the vehicle so for us not an issue.

As for a scrubber I've incorporated that into an exhaust stack, whilst doing markets we avoid where possible cutting any plastics, but we engrave heaps of pre cut stock. Going mobile is easy enough but there's no cheap solution.

[Craig Matheny]

For those of you running an Epilog laser not any others look at what power supply you have in it most will have psp600 or one of the others http://www.powergatellc.com/pdfs/PSP-600.pdf this is the spec sheet these units already have surge and power protection built in half way down the sheet talks about it.

[Joe Hillmann]

Before you make further investments, have you talked to them about the exhaust fumes? I can't imagine any of the flea market/craft fairs indoors or out allowing that without a really good scrubber system which would require even more power.

At the flee markets they don't care they have people there running loud construction site generators so mine should be no concern. Right now I have it running about 2 feet from my building and have an extension cord running through a window to a computer and the fans on the computer are louder than the generator.

[Joe Hillmann]

I've been running a mobile set up for over two years, and don't have any issues running from batteries through an inverter. We have 6 x 6 Volt 225 amp batteries connected to give 675amp at 12 volt. This gives us enough power for a full day of heavy use. We have run direct of a 2.5Kva pure signwave generator again without issue but I prefer to run from the batteries and if needed just use the generator to charge the batteries. Bear in mind our battery system alone weighs over 200 kilos but its all permanently mounted in the vehicle so for us not an issue.

As for a scrubber I've incorporated that into an exhaust stack, whilst doing markets we avoid where possible cutting any plastics, but we engrave heaps of pre cut stock. Going mobile is easy enough but there's no cheap solution.

Steve,
Can you explain about the scrubber a bit more? I was thinking of running the laser exhaust through an activated carbon scrubber and if I end up getting set up at a place where I can't put the generator out in the woods then running the generator exhaust through the same scrubber. Is that kind of what you are describing?

[Steven Cox]

Steve,
Can you explain about the scrubber a bit more? I was thinking of running the laser exhaust through an activated carbon scrubber and if I end up getting set up at a place where I can't put the generator out in the woods then running the generator exhaust through the same scrubber. Is that kind of what you are describing?

Joe, have a look at Dan's thread DIY air filtration unit for <$200 I've posted some pics of my scrubber based on Dan's idea. I will say that my original fan packed it in so to replace it I'm now using a 150mm Inline fan that's commonly used in air conditioning systems and it works even better.

Regards Steve.

[Joe Hillmann]

I am doing a test run of the laser powered by the generator, so far so good. I ended up getting the generator I mentioned earlier then got a battery back up ups to further condition the power.

Edit: In the middle of my test run I compleatly lost power, everything shut down. My first thought was I ran out of gas. When I went to check the generator was still running. My next thought was that I was somehow drawing too much power, I did the math quick and I wasn't even close to using 1/4 of the continued use power the generator is rated for. Then I thought maybe I got a defective generator.

It turned out the generator had just slowly vibrated itself away from the building and unplugged the extension cord I was using. Now I am waiting for the computer to reboot to test it again.

[Steve Busey]

It turned out the generator had just slowly vibrated itself away from the building and unplugged the extension cord I was using.

:rolleyes:

Glad it's the most non-technical issue that set you back. Might try tie-wrapping the cord to the generator frame to prevent additional disconnects...

[Mike Chance in Iowa]

It turned out the generator had just slowly vibrated itself away from the building and unplugged the extension cord I was using. Now I am waiting for the computer to reboot to test it again.

LOL Now that's something that would happen to me. :) .... also try to remember that if you chain the generator to something, like an RV or truck, that you unhook the chain if you decide to run into town for a quick errand. (Yeah, that almost happened to me when my Sweetheart for some unknown reason unhooked the chain from the RV and hitched it to the truck just before I was about to leave and I didn't know it! Fortunately I eased out and saw the generator move in my mirror!)

[Joe Hillmann]

:rolleyes:

Glad it's the most non-technical issue that set you back. Might try tie-wrapping the cord to the generator frame to prevent additional disconnects...


My heart was in my throat for a minute there before I figured out the problem.

[Glen Monaghan]

:rolleyes:

Might try tie-wrapping the cord to the generator frame to prevent additional disconnects...

Probably not the best idea unless the generator gets fastened down so it doesn't move and pull on the cord, and then it wouldn't be necessary anyway. Something else would have to "give" if the plug can't just pop out when the generator "walks"; might be the cord snaps, window breaks if cord goes through a window, door frame gets crunched if going through a door, etc.

-Glen