This topic has been moved to [WANTED].

https://www.lighting-gallery.net/index.php?topic=18608.0

I am no longer a mod so i cannot move this myself. But if you could move this to "wanted" that is where requests for stuff go. This forum is for stuff you are selling. And I created "Webfinds" for stuff you find listed online like on Ebay and marketplace.

@RRK
I was thinking of possibly making my own switch, or maybe using a multiple pole switch with all of the poles in series to make a higher breakdown voltage.

I did not know that MH lamps needed "high ignition energy", that is news to me. I wonder why this is. If it comes to the point of me having to make my own ignitor circuit, at that point it is probably just easier to just buy the appropriate ignitor.

@Ash
The particular transformer I have is completely magnetic (60hz), just a high leakage autotransformer. I should have mentioned that in the original post.

I have several random ferrite cores that I salvaged from various switching power supplies that I could use for making an ignition transformer, but I probably won't end up doing that.

In addition to what's said

Those transformers work at high frequencies, and the winding have sufficient impedance to support it

Connecting 50/60Hz voltage across its output is equivalent of connecting DC. The wire resistance of the secondary is probably a few kOhm to . With low frequency voltage in the order of ballast Voc or lamp Varc, it may dissipate significant power, possibly enough to be destroyed

Which gets me thinking, can this be overcome with a small capacitor in series (something suitable for the voltage, like a string of 1kV..2kV capacitors and equalizing resistors)

Winding a superimposed pulse transformer can be done with with ordinary ferrite cores of the order of ETD38, but some consideration must be made to insulate parts of the winding which are electrically distanced from each other (the wire enamel is not sufficient where turns from different layers may touch)

The fact that the same dirt don't going downward, meaning it is outside the arctube wall rather than inside.

I have a 70 MH lamp (GE if I remember right) that has the same inside...I always just assumed it was halide salts deposited on the glass when it cooled after running.

Getting a good high voltage switch capable of a few amperes of a HID lamp combined with >5kV withstanding and reasonably fast working is possible but not easy.

Also, while this may work for some lamps having low ignition energy like HPS, many lamps need a certain relatively high ignition energy and some OCV voltage presence with a low impedance at the same time to do glow-to-arc, likely this applies to metal halides.

Much easier is to wind your own superimposed transformer or borrow it from something that is not potted, like 150W electronic ballasts. Two or more of  identical transformers can be run in parallel for higher current. A primary of the ignition transformer can be driven by some trivial means (spark gap, SIDAC, etc)

The lens of my tracklight is made from regular soda lime glass. It would break in the case of arctube explosion.

The ballast is designed to last 10 years, and there is an underlying assumption (which is not always correct) that it is not stored for too long from manufacture to when it is put to use

The PME's will last 10 years, the problems with them start sometime at 20 years or older

Plastic film caps with the minimum voltage ratings (typical 275V) may fail already within the 10 years. The capacitor locations in the ST ballast don't suggest that they are EMI capacitors - They may be things like DC-link or even in the lamp circuit, although the type of capacitor does suggest EMI (all other capacitors in the ballast are not in X or Y positions, so typically manufacturers use there capacitors without X or Y ratings)

If then we ask why a bit higher voltage rated caps are not used, that's because the manufacturers don't deem it necessary to overdo if it seems to fit by ratings

(And hey, the electrolytic cap is typically rated for 15 years from the date of manufacture, as an additional limit besides the hours rating)

If they would want a ballast that is likely to last "unlimited" life, and assuming the manufacturer's engineers are aware of the PME failure mechanism, the capacitors would be indeed some plastic film but with 1.5x+ voltage ratings, which would also be bigger in size

In few cases a PME may also last for many years beyond the 20 year line, if it is working in conditions that prevent the failure from happening (see Perfektstart example). I don't think it was intentional (or that the failure mechanism was known at all) back when those Perfektstart ballasts were designed, but nowadays if a PME is used in a similar way, it may not be a significant limiting factor in the ballast's life. (HF ballasts are not enclosed enough, and dont have components that get hot enough for this to work for them)

And, you may be surprised how much common knowledge of us electronics amateurs (and those of us who became engineers) is completely alien to absolute most of engineers working in design of devices. This goes well beyond being familiar with failure modes of some components

I am in possession of a 3600V 8mA neon sign transformer. This means it has peaks of a bit over 5kV, which is around the voltage of an electronic ignitor. This transformer can run 24/7 with a dead shorted secondary, and just get a little bit hot. This means I can safely put just about anything across its output. It also has an isolated secondary, which is important. Here is my plan for making this into a universal HID lamp ignitor:

For this explanation I will separate the secondary leads of the neon sign transformer into H1 and H2 just for clarity purposes, though there is no practical difference between the two.

- Connect the COM wire from the ballast to the socket's neutral connection (as per usual)
- Connect the H1 wire from the NST to the socket's neutral connection
- Connect the H2 wire from the NST to the socket's live connection
- Connect the LAMP wire from the ballast through a high-voltage tolerant switch to the socket's live connection

1) Starting with the high-voltage tolerant switch in the OFF position, power is applied to both the NST and the HID ballast. This strikes a low-current arc through the discharge tube of the lamp.

2) With the arc struck, the switch is then flipped to the ON position, applying the ballasted output of the HID ballast across the lamp (and also the secondary of the NST, which should be able to handle this at least temporarily). This ballasted output applied across the transformer would essentially just short it out, which is ok because it seems to have no complaints about being shorted.

3) Now with the arc properly struck, the NST is doing practically nothing, so its primary may be disconnected.

If I had access to a PSMH or HPS lamp I would try this out, but I own neither of those types of lamps. Do you think this would work? Obviously you might have to try flipping the switch a few times depending on what part of the AC cycle you flip the switch, but I think this would work. Ideally the NST wires and ballast wires would be phased so they are both positive and negative at the same time, but I don't really think that would matter if you got it the other way around. I could be wrong though. What do you think?