71   General / General Discussion / Re: Distortion Power Factor Inconsistencies?  on: February 06, 2026, 01:32:39 PM 
Started by Multisubject - Last post by Multisubject
@Ash
Quote
The actual lamp power may be different from the rating. See if you can find the real lamp power, or if it lines up better if you assume something like 39W instead of 35W for the lamp. (This still have to be verified, but lets see if this would explain anything)

The formula used is correct for Xbal, not for Zbal. They are not too much far away from each other, this alone would not likely cause as high differences as you see. Unless you have a formula that can account for Xbal and Rbal separately, use Xbal and disregard Rbal
On page 44 there is a ballast curve for this lamp, and it does use wattage as the y-axis. Maybe this is just relative wattage, but at 52V is does say 35W.

Is there a way to calculate the actual usable power factor without having every single spec of this lamp?

I was thinking the same thing with the X and R. I could make a formula that uses both, but I don't know how to get the X and R of a ballast when all that is given to me in the standards is Z. So whatever, Z probably good enough.
 72   General / General Videos / Re: 400W MH lamp Bursts and Keeps Running!  on: February 06, 2026, 12:52:14 PM 
Started by Multisubject - Last post by Ash
The actual lamp power may be different from the rating. See if you can find the real lamp power, or if it lines up better if you assume something like 39W instead of 35W for the lamp. (This still have to be verified, but lets see if this would explain anything)

The formula used is correct for Xbal, not for Zbal. They are not too much far away from each other, this alone would not likely cause as high differences as you see. Unless you have a formula that can account for Xbal and Rbal separately, use Xbal and disregard Rbal
 73   General / General Videos / Re: 400W MH lamp Bursts and Keeps Running!  on: February 06, 2026, 12:22:31 PM 
Started by Multisubject - Last post by Multisubject
I found it very cool that the pressure was allowed to decrease so much, but the electrodes were still kept hot enough to function as they normally would. It would be cool to see this started again and see the discharge that would likely occur between the support structures
 74   General / General Discussion / Re: Distortion Power Factor Inconsistencies?  on: February 06, 2026, 12:19:24 PM 
Started by Multisubject - Last post by Multisubject
@Ash
Yes, by PF I mean the distortion power factor of the lamp discharge itself, not any inductive/capacitive displacement power factor of the ballast and the lamp together.

By calculating the lamp current times the lamp voltage (.83 * 55), you get 45.65 VA. 35 W divided by 45.65 VA gives you a power factor of .77 (if I am doing this right).

By ZBal, I mean the total ballast impedance in ohms (including both inductance and DC resistance). I found it on this 2009 ANSI standard sheet, so I can only assume that it is correct and not causing my problem, though I could be wrong.
 75   General / General Discussion / Re: Distortion Power Factor Inconsistencies?  on: February 06, 2026, 11:28:30 AM 
Started by Multisubject - Last post by Ash
If by PF here you mean the lamp discharge PF, 0.77 looks too low. 0.85..0.9 is normal. Could it have been calculated before with some error there ?

If you mean PF of the entire circuit, that would not appear in the equation at all (the sqrt( voltages ) in the formula already takes care of it). And 0.77 is way too high for a discharge lamp without capacitor

Also, by Zbal do you actually mean Zbal or Xbal, and how did you find it ?
 76   General / General Videos / Re: 400W MH lamp Bursts and Keeps Running!  on: February 06, 2026, 11:18:50 AM 
Started by Multisubject - Last post by Ash
At and after the moment of burst, the existing hot spot is still on the electrodes inside the arctube, not on the external conductors and frame. So the cloud of thermal emission of electrons and consequently path of least Vdrop is between the electrodes in the arctube, and the arc keeps burning there

The pressure in the arctube must have been extreme, if even after the gas volume expands to the whole outer (and pressure drops accordingly) it still keeps a high intensity discharge. This probably would not happen if running on the correct gear
 77   Lamps / Modern / Re: Does Transporting BT-shaped Mercury Lamps Cause Looseness?  on: February 06, 2026, 08:59:50 AM 
Started by Maxim - Last post by Maxim
@James — I see. I believe that is what happened with two of my lamps; they somewhat "slipped" out of place, making their rattling more pronounced. But no permanent deformation.

Is there any way to make the frame "slip" its way back in place? Thanks for your reply!
 78   Lamps / Modern / Re: Does Transporting BT-shaped Mercury Lamps Cause Looseness?  on: February 06, 2026, 06:53:08 AM 
Started by Maxim - Last post by James
Normally not.  The support frames are usually made of nickel with 2-3% manganese addition, to pin the nickel grain boundaries.  This gives the material surprisingly good elasticity.  Of course if you apply sufficient force to take the metal beyond its yield point then a permanent deformation could happen.  Also in case of shocks while hot thar can happen more easily.  But I would not be too concerned about transport by car.

What could happen is that the quartz arc tube becomes a bit looser in its metal clamps to the frame.  The quartz pinches are often a bit irregular in shape, and the metal straps do not always clamp them at their widest points.  Small movements may cause the arc tube to slip between its supports, and if it is thinner at that point it may then rattle more.
 79   General / Off-Topic / Re: Incapacitating a microwave directed energy weapon  on: February 06, 2026, 01:36:02 AM 
Started by lightsofpahrump - Last post by Laurens
I don't think an offensive strategy here is wise. Defence is key here.

You can completely forget trying to disable the computers. Just beaming radio waves at it won't work because modern *professional* electronics are usually well shielded. Especially stuff that literally is sending out radio waves. Look at what people are doing with tesla coils. Those things create MASSIVE field strenghts of RF energy (they are literally based on the technology of 1900s era radio transmitters/spark gap transmitters), yet people's cameras are still running just fine, and midi control boards for musical tesla coils are only occasionally glitching out.

An EMP will take a capacitor bank mounted to a box truck with an enormous coil to induce currents in that machine. Unrealistic, *properly* weapons grade (as in 'you are now not a civillian anymore but you're using military scale power against the government) and there's no way to validate its effect against the devices you want to put out of service until you actually have access to one of those and a plot of aussie outback where you can do those tests. You cannot do those tests without being noticed by the authorities, because the EMPs will propagate like easy to receive radiowaves at a distance.

Now, what can you do? Well, that's fairly simple. Buy a roll of super fine stainless steel, thin, flexible fly screen or filter mesh. Make this into full body coverage garments that you wear over a long sleeve shirt and trousers. Ensure all seams are folded over and stitched together firmly so everything makes electrical contact. Connection between shirt and trousers of the garment should overlap generously.

On the condition that the holes in the screen are smaller than the wavelength of the microwave weapons, this will essentially reduce the power your body absorbs by 100-1000x.

As a bonus, this will also protect fully against stun guns/cattle prods (it'll short them out) and diminish the effect of tazers (the darts will still stick into your skin, but part of the energy will be conducted through the mesh. This does come at the risk of sparking on the skin causing small burns, but that is preferable over being shocked and incapacitated).

Of course i have not validated the effect of protective clothing like this. I am a ham radio operator but generating legal limit power at the frequencies used by those weapons (many GHz) is really hard. And tbh, i'd be scared shitless if i were to concentrate that amount of power on part of my own body, even with a suit that theoretically should protect against it.

It's something i've been thinking about since the rise of authoritarian politics both in my own country and abroad. I actually have a roll of copper plated textile mesh sitting around i bought on Aliexpress and it is indeed actually properly conductive, so plated textiles may also be doable. But i don't know how durable the plating is, whether it won't just wear off after a few hours of wearing, and how much power it can dissipate or reflect before flashing off.
 80   General / General Discussion / Re: Why do cars not have cornering lamps?  on: February 05, 2026, 10:20:46 PM 
Started by Cole D. - Last post by Econolite03
This is very common with most Jeeps, including the newest generations—regardless of the model. I don’t think Lexus is capable unless it was added on, never heard of it.
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