It varies per market, EU market cool white is almost always 4000k.

Just market preferences and customs, i think.

What I’ve noticed, is that many newer cool white LEDs are 4000K instead of the 4100K of fluorescents. These colors are not significantly different but why are the LEDs 4000K instead of 4100K for most?

Also, why are cool white fluorescents 4100K and not 4000K? That’s another one to point out

Actually, some displacement pump like rotary vane may be in use! Why? Turbines struggle to get really good vacuum and do this with poor efficiency, especially small ones. Look at a regular vacuum cleaner motor-turbine. Rather complicated mechanics here, including multiple turbine wheels in series. And it eats up to 2kW to get the job done satisfactory, modern 'green' models suck literally))

The modern 900w models of good brands designed in EU are actually really quite good. My parents had a 2kW AEG and a 900w AEG, they perform equally well, except the 900w one is much quieter. Sometimes you can find actual suction power specified in watts. A 2kW aluminium wound (for cheapness! Sacrificing efficiency) vacuum cleaner motor can perform worse than a 900w copper wound motor.
Brands like Nilfisk, extensively used in professional cleaning, kept using their 900-1000w motor units for years into the era during which consumer vacuum cleaners reached 1500-2000w.

For energy consumption it's not a big deal imho, vacuum cleaning takes maybe 15-30 minutes per week? So in that regard i don't care about the regulations. But what was a very nice side effect, is that vacuum cleaners have gotten a LOT quieter. Though there are rules about that too, limiting noise to 80dB or so.

What works like crap are things like a bagless 600w Philips (Oh philips, how far you've fallen) designed and made in China. That thing performed on par with a 500w Holland Electro from 1960... I've had 2 bagless ones, both were crap.

I don't think they use a rotary vane, just a smaller but higher RPM centrifugal pump/turbine. Multistage vacuum cleaner motors aren't something special, aforementioned Holland Electro already had 2 and 3 stage fans in the 1960s. I haven't disassembled a modern, well performing vacuum cleaner motor yet.

If it truly sounds like a piston pump, there's only one explanation: it is broken, or in the process of breaking. I've had a Hoover Junior from the 1940s of which the rear bearing bushing was worn, and it made quite a nasty roaring racket. Usually those old hoover motors run pretty smoothly. 

May be ignitor-integrated D1 lamp or D2 combined with an ignitor socket will have a chance. Don't know exact ignitor schematic though, so no idea if it really needs a DC phase of lamp voltage present with automotive ballast at start to generate ignition pulsed successfully.

What brand is it?

I have a well used 70W HPS similar to this.  yellowing of the lens cover. 

Happy new year to all!

Given the arc voltage tolerance and so the range of the corresponding actual arc current variation any arguing whether the "correct current" is 0.45 vs 0.5A is rather moot, it is just arguing what "nominal current" label should be placed for the whole range the things operate.

More important is the exact power tolerance, mainly including factors like mains voltage sensitivity of the magnetic ballast, plus the current crest factor.

And also do not forget the auto MH do not anticipate anything but square wave LFAC feed, the mains zero crossing reignition characteristics is just a completely unpredictable huge unknown, could be OK for one lamp and a complete disaster for other even when both are the same formal specs.

And obviously the mentioned ignition/startup problems.

It is also worth to mention that Schréder released also a LED conversion kit for the Furyo lantern range. One just has to replace the lamp socket with a LED module and the ballast with appropriate LED driver. According to my former workmate from Schréder there are some installations with them in France but he could not tell me if they were any good or not.

I would have a few but shipping from CH is extremely expensive I think. Picking them up would be the best solution.