Update: I wanted to make a video of it working, and soon discovered that the said noise is only my hearing illusion: The piston pump like noise comes from the brushes and it have the usual turbine sound.

@stillaintjeff24
Thanks for offering! It seems to be very difficult to get people to do this kind of thing.

Anyway, if you have a low voltage transformer like a thermostat or doorbell transformer, you can use that (or if you happen to have a variac). Just use the same input voltage for both tests, preferably 24V or below. Using any cheap multimeter should work just fine since there won't be a lamp connected.

Test 1:
Connect the ballast as usual, but where there would normally be a lamp connected, just short the two wires. Measuring the current with a probed ammeter or a clamp meter, record the value when it is running.

Test 2:
Same setup as before, except this time the capacitor will also be bypassed. Record this current as well.

The difference between these two currents will hopefully be able to answer our questions. With MH ballasts, the capacitorless current is much much higher than the current with the capacitor connected, we shall see how this compares to HPS ballasts. Let me know if you need a drawing of how to set this up, you know how I love schematics lol.

Anyone trading/selling Power Grooves within the EU? Especially F96PG17
Preferably multiple so sending a transport company for pick up is worth it.
High prices are ok

Happy New Year to you all

The noise hears more like that of a piston pump.

No thallium appears when I see the spectrum of this lamp run-up. Also, the yellow doublet and blue line of mercury are also strong.
Also: The lamp would be greenish if thallium would be present, and it isn't the case.

How do you know this? Tl 535nm is rather close to Hg 546nm, hard to tell on uncalibrated spectrum. One way to tell is to look at run-up. At start, only four Hg lines present, as the burner heats, nearby Tl green line appears, and later usually over-dominates green Hg line.

Or something stuck around the impeller 🤔

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))

There is no thallium in the spectrum. Only mercury and dysprosium. The green line is of mercury.