Hi all, I don’t have my laser yet, (waiting on shipping stinks), but I’m trying to get everything all set for it. I’ve ordered a new air assist head from lightobject, and an 18mm lens to go with it, I have the hose and compressor for the air assist, a 5 gallon bucket with lid, 3 gallons of distilled water and a jug of automotive coolant, laser safety goggles, and a whole mess of switches (for interlocks).
What I’m really wondering about is the 10k wirewound multiturn pot that I ordered to replace the stock pot. I was lookign at datasheets on laser power supplies and they generally specified a 5k-10k pot, but it looks like these use a 1k pot. Is the 10k going to be an issue?
from what I understand it’s just being used as a voltage divider as a reference for the output power of the machine, so personally, I wouldn’t think it too terribly critical.
http://www.ebay.com/itm/161246422730
Welcome here Eric,
You will be able to start in a snap with all that. saving a lot of time by doing only one miror alignement and so on… ;-))
I am glad this community is able to help, thx for reading.
The 10K Pot won’t be a problem - that is what I use on mine after the upgrades I did
Well that’s good to know. I was considering a PWM control, but after learning that the reason it needs a 20kHz PWM is because it doesn’t smooth it, but rather pulses the laser at full current, I decided this is a better option.
On a side note, do you know if it needs the 2w handling if it’s just a reference voltage? I want to run a dual motorised pot from a micro controller, but can’t seem to find one rated above about .5w
I shouldn’t think it would need the 2 watts.
P=E²/R.
so, with your half watt pot, lets assume 10k, we know volts(E), and we know resistance®;
(5)²/10,000 = 0.0025 watts, or 2.5mW. In other words, you’re fine.
well, I mean, on the lower end you are looking at 2.5 watts if you have it turned to like 10 ohms, but I would imagine theres some sort of resistor involved elsewhere.
Cheers, that means I get my mico control, presets, precise settings and remote operation without really modifying the existing electronics.
So you are basing it off a 5v level? I suppose I could measure the current through a multimeter then.
I am basing it off a 5v level, yes. That’s what the laser PSU seems to be putting out.
It doesn’t need the 2W rating - I am using a 100mW cermet trimmer. Remember that the power supply will produce more power than the laser tube will handle. I have my pot set to a maximum of about 50%. This gives a maximum laser current of around 18mA which is the upper limit for the tube. Any more than that and you shorten the life of the tube significantly