first light: my SP168 actually works!

[GooeyGus]

Thanks Pat,
That was the exact info I was looking for. I just didn't know if the PSU could somehow cause damage to the head itself. I'm new to these 3-phase lasers so I guess it's always better to be safe than sorry. For all I know there could have been a PT self-destruct circuit built into the PSU if it senses a malfunction. Tube blows up and shatters into pieces.

Thanks again for the info, I'll keep you on speed dial

[Laserman532]

Thanks Pat,
That was the exact info I was looking for. I just didn't know if the PSU could somehow cause damage to the head itself. I'm new to these 3-phase lasers so I guess it's always better to be safe than sorry. For all I know there could have been a PT self-destruct circuit built into the PSU if it senses a malfunction. Tube blows up and shatters into pieces.

Thanks again for the info, I'll keep you on speed dial

When you get the supply hooked up to three phase power and get the water so that it will flow with no leaks. Here is your quick test.

a- using a dvm measure 208vac phase to phase and 110v phase to ground FIRST. If you have one hot leg remedy that problem. Start your water flow.

B- get a boyscout compass ready. If you lift the breaker you will see the cathode start to glow. 30 - 45 seconds later the time delay relay will close allowing the start light to light (it will if your relay is working and if you have doubling voltage)...DO NOT PRESS START BUTTON YET.

c- take your compass and hold it close to the brass ring of magnet on anode end one end of the compass will point strongly to the anode. Slowly move your compass towards the cathode end of the magnet. You will see the compass switch needle ends. This tells you the magnet is working, it dosnt tell you how strong it is but it tells you that it is working.

D-Get your DVM set it to a high voltage range DC. Put the red probe in the center of the set screw of the red wire attached to the anode. (this keeps you from slipping off) Put the black probe on one of the cathode wires. DO NOT PUT YOUR PROBE BETWEEN THE CATHODE WIRES Put your probe on the outside of either one of the wires. You should measure approx 540 vdc. If you measure 540vdc you may REMOVE THE TEST PROBES!!!!! (warning if you hit the start button with DVM connected it will EXPLODE VIOLENTLY IN YOUR FACE) may be I should have said to put on safety glasses

e- When you measure 540 vdc that tells you that your voltage doubler ckt in the ps is working. IF you only measure 220 to 250 vdc YOU HAVE A PROBLEM in your doubling ckt. (i will have to clean some cobwebs to figure that out)

F- if you measure around 540vdc REMOVE PROBES and push the start button with the current control pot set to minimum. (have your hand ready to throw down the circuit breaker on the front panel if it runs to max current) (But it wont, it will be just fine) Your plasma tube will start and have the video camera ready because you will have to post the video of you guys doing the ceremonious dance in the endzone.

G- if it starts fine and you have current control. Increase your field control to max and slowly turn your current up to 30 amps. At 30 ammps field max you may measure the tube voltage and it should be in the range of 237 - 243 vdc./ If it is not in this range you should call me and I will give you personal guidance as to what to do next. DONT WORRY ABOUT LASER LIGHT AT THIS POINT. Lets get the plasma tube to operate correctly first.

Sorry for long post but I think it was important i gave you some details And you guys may know some or all of this but this was a little information to the rest of the community who may want to do this someday

[Xytrell]

The first thing to go is the cathode tranny voltage regulation as you load your pole pig.

I think you misunderstood me. I realize he can't take it to full power because the voltage from the phase converter will drop too low. However, As long as the voltage from the phase converter is at 208V or more, the PSU can regulate everything properly.

[Skyko]

This is true, as I was monitoring the phase to phase voltage from the two real legs to the third generated leg and never saw it drop below 219 volts using a Fluke 189 true rms meter. Based on this I have no reason to believe there would be any incorrect drive in the cathode voltage regulation, although as I mentioned I have only taken the laser up to 800mW according to the doctor's control panel. I do believe that it is doing a bit more than that in actuality though...probably 1W or so. I think Gooeygus will bring his power meter when he comes over so we can better tell.

[mixedgas]

, the PSU can regulate everything properly.[/quote]

Yeah, but you still have to check RMS current to the cathode as you climb up the current ladder. It will work just fine at 208 at start, but when you get greedy and want 30 amps down the tube, there are issues with phase converters. Harmonics and such as well.

Usually you see the building lights sag too.

Steve

[Xytrell]

Yes, I think we can all agree 30A probably won't happen in a basement

[GooeyGus]

Here is what will or could happen... ...it works fine (current control & magnet control functions) open many beers...

So is the beer a requirement for the 265 PSU's? Is there any certain type of beer I should buy that may ensure the best success rate?

I knew you SP engineers were a bit wacky... but this is the first I've heard of a PSU running on beer...

[dar303]

This thread makes med want a "real" laser too!
I have a few diode and DPSS lasers and a Synrad CO2 but...I NEED MOORE BIG LASER STUFF!
What a pity that they are so scarse in Sweden, things like these never escapes from the medical or science industries, I guess they just go off to recycling!

[Diachi]

This thread makes med want a "real" laser too!
I have a few diode and DPSS lasers and a Synrad CO2 but...I NEED MOORE BIG LASER STUFF!
What a pity that they are so scarse in Sweden, things like these never escapes from the medical or science industries, I guess they just go off to recycling!

Your on post 168, in a thread about SP-168s

I want a large frame argon like a 168, and I can't find one anywhere, I would hate to miss one by a week or two that went to scrap

[LaserLover]

A sagging cathode is physically a sagging cathode. If you crank up the laser tube power too high for too long the cathode filament can sag/bend/distort in such a way that if it sags into the plasma stream within the resonant cavity (between the HR & OC mirrors) it can interfere with the laser operation and diminish the power output or stop lasing all together. You're very lucky the SP168 fired up after all this time. I made my own phase converter using a 7.5 HP 3 phase motor to fire up a Lexel 95 Argon laser and I found that I wasn't able to crank it up to maximum power without the motor starting to overheat. If you had a 10 HP motor that might do the trick and give you 30 amps but your main breaker might also kick out before long. You should also be using a 3 phase multitap transformer to match the voltages on each leg of the output from the phase converter.