Chinese laser question about trigger voltage.

[Greg Facer]

Hi everyone. I'm still working through yet another round of glass tube failure under warranty issues with Shenhui and decided in the meantime I get an 80w Coletech tube. I had read on here that generally the feeling was you could use a larger power supply on a smaller tube and not vice versa.

But, after ordering of course, I re-tread those posts and the difference was 100w to 80w ( or similar) and not so extreme as a 150 w to 80w. The milliamperes I can control by starting low and moving up slow, but reading the documentation by RECI, the triggering voltage is the big variance. So I'm wondering if that will potentially blow my tube even if I can dial down the power output. (assuming DHL hasn't already, they neglected to leave it at the airport as I requested).

Anyone know exactly how these work? Thanks in advance!
Greg

[Greg Facer]

Thanks everyone for looking! I just went ahead and bought the proper power supply. At least the tube arrived by DHL unbroken, a minor victory in itself!

Greg

[matthew knott]

be surprised if you can blow a tube with trigger volatge, the longer the tube the higher volatge you would need to strike the tube, i would think worse case if you went for a higher power laser with a low power psu it would just not light. Running the tube at a higher than rated current is another story.

[Greg Facer]

Yeah, I figured out why the longer tubes would need the higher trigger voltage, but the bottom line is higher voltage at a given milliamps is more power and I don't know what effect that would have. Shorter tube life?

The real kicker for going the safe route was that one of my possibilities of the last failure was a defect in the glass. A higher voltage is not only going to arc easier to the other end, but maybe try to arc through the glass or to a contaminate in the glass. I figure lower voltage is good in that sense.

If only I actually understood these things! I wonder if the Chinese do?

Greg

[matthew knott]

the impedance of the tube is fixed, the current is adjustable but lets assume its fixed say 10mA, this would mean that the voltage would have to adjust on the psu to keep the current at 10mA. The maximum volatage of the psu is just that, it does not mean that while its running is sitting at the maximum voltage. therefore as long as the current is correct there will be no 'wear' on the tube. Basically you wont have a higher voltage at the same current.