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FrozenGate by Avery

So have I been running my hene PSU switch at 230v this whole time?

J

joeyss

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Jul 23, 2008
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The switch said 230v when i got it. I switched it to where it said 115 and the green led got much brighter like double and when i'd shut the laser off i'd hear a slight discharge sound. Should I leave it in 115volts? is that the right setting?

I'm amazed it lased at all if my psu was set to run off half voltage.


Will my 612nm be any brighter after it warms up or should I leave it at 230v?
 





I must say, I'm surprised it lased at all st at 230 VAC when you have been using 110 VAC. I would say, leave it in the 115 position. I would have expected it to sputter at least in the higher setting.
 
Will it get brighter at 115 after like 30 mins?

is the shut off sound normal?
 
He-Nes use a higher voltage spike to start the laser, but the run voltage is much lower. I can't say that I remember hearing a discharge sound from any of my He-Ne lasers. It is as bright as it is going to be after it starts lasing.
 
Last edited:
paul1598419 said:
He-Nes use a higher voltage spike to start the laser, but the run voltage is much lower. I can't say that I remember hearing a discharge sound from any of my He-Ne lasers. It is as bright as it is going to be after it starts lasing.
Click to expand...

Only does it on 115 when i shut it off or on and it's low

the power supply is from 92 the laser 94. 6.5ma


It's just weird it didn't sputter at all cause i read the laser faq yesterday they would hardly work if at all at half the voltage.
 
I don't understand the question. Are you asking US where you had the switch?

If your wall voltage is 115V, your input selection switch should be set at 115V. It's not complicated.
 
Cyparagon said:
I don't understand the question. Are you asking US where you had the switch?

If your wall voltage is 115V, your input selection switch should be set at 115V. It's not complicated.
Click to expand...

it was set to 230v on back of the psu switch. I moved it to 115 and the led on the power supply got much brighter. How the hell was it lasing set to 230 vac but running on 115?
 
Switchmode converters can operate on a wide range of voltages. The switch likely enabled a voltage doubler that was otherwise inactive, which would make the circuit more efficient.
 
I have to agree. The switch is there to maintain the correct input voltage, and you should leave it in the position that corresponds to the line voltage you are using.
 
Obviously, but i guess you are wondering why the laser powered on at all at 'half voltage'.

This probably has to do with the transformer itself. These transformers have secondaries with a lot of turns of very thin wire, giving them quite a bit of resistance. Under normal operation voltage quite some voltage is dropped across that resistance.

When you power it using half the input voltage the output voltage will be lower, but not quite half, as the current across the tube drops considerably and so does the loss due to resistance in the transformer. Apparently in this case there was enough current delivered for the unit to still lase, albeit at lower power.

You should keep in mind that not all loads are linear resistors. For example, if you plug in a 100 watt lightbulb intended for 230 volts into a 115 volt output, you would expect half the normal current to flow, and at half the voltage a power consumption of 25 watts. In reality it's considerably more because the filament doesn't get as hot and hence has lower resistance.
 
If it's like every other HeNe PS brick I've played with it uses a resonant switch-mode topology. The resonance part of the equation is how the thing managed to start your laser tube when it was set for 220V. As to the laser being brighter....probably not but maybe just a tiny bit. The circuit will be very much more efficient set for the correct input voltage.
 
Benm said:
Apparently in this case there was enough current delivered for the unit to still lase, albeit at lower power.
Click to expand...

All the HeNe PSU bricks I've seen are switchmode, most of which can usually operate down to 80-90VAC. I'm not so sure the power would have been less at all. A DMM would confirm that, but few people here seem to own one :tinfoil:
 
Switchmode power supplies usually don't have the input voltage selector switch.

HeNe tubes can run at reduced current/voltage once they have been started though: they need a considerable voltage to fire up, but after that they will run on a wide range of voltages with variable output power.

You could investigate this further with the laser running from a variac. Chances are you can reduce the input voltage far below nominal once the tube is fired up. It's even possible to go to a non-lasing 'glow' mode back up to lasing mode when testing this. The hard part on these lasers is the initial strike, not maintaining discharge after that.
 
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