When I was in Eltam factory, I said the factory engineer, that except their ES-50 semi-parallel ignitor, I've not seen any youtube video of an external ignitor HID lamps hot restrike with low frequency pulse, that gave me the thinking that Eltam is pioneering this type of ignitor, and that it isn't produced worldwide.
Than the engineer remainded the Philips SN58 (This is the only ignitor that he knows worldwide from the same type of Eltam ES-50), as an ignitor that makes low frequency pulses.
But Medved said somewhere, that this ignitor (SN58) makes 50hz pulses. A thing which causes misunderstanding which is correct: Medved or the factory engineer of Eltam.

The difference could well be the ignitor type: I was always describing the SN57, I don't know, how the SN58 differ from the SN57.


And the low frequency pulse ignitors were here quite common about 30 years ago (TZ-1,...), they were in the form of an aluminum can, about the same size as the can capacitors...
The low frequency was more a result of a compromise (given existing components, materials and circuit knowledge - some topologies were not known yet), not the ideal "wanted" functionality...

One obvious difference between the SN57 and ES50 is hte position of the tap on hte ballast - in the ES50 the tap is near hte lamp - you have to flip hte ballast between SN57 and ES50

But i seen other ignitors which ae atleast wired the same - examples are the Shingotignitor i found in my HPS floodlihgt (the ignitor is not working) and a Fris Electromechanics ignitor which i have from an Afula floodlight which is blown up - possibly again due to water damage

This is the Shingot ignitor

The Steinitz ST1C (from late 80s) is wired same as the SN57 however. Its construction is very simple, like 8 components or so. The silicon present in it are a BT138 and a diac

author=Ash link=topic=2878.msg18497#msg18497 date=1358839301]
One obvious difference between the SN57 and ES50 is hte position of the tap on hte ballast - in the ES50 the tap is near hte lamp - you have to flip hte ballast between SN57 and ES50
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It is not that simple, even when the diagram look so, the tap position differ:
The SN57 require tap in 25% of the winding (for 3..5kV pulses; they use resonance to get ~800V pulses on that tap, so the ballast multiply that by only ~5x),
while the ignitors with the tap close to the lamp end require it to be at ~5% from the lamp end, as they generate only about 200V on between
the tap and lamp end (so the ballast should multiply that by ~20x).

So using the wrong ballast/ignitor combination would yield to either too low ignition pulses (about 1kV, when using the second ignitor with ballast with tap at 25% from the lamp end; but many HPS would still ignite on that), or too high pulses when the lamp is missing or failed to ignite. Again, with good lamp this combination does not show any bad behavior (it ignite the lamp well), only the ballast insulation would fail soon, once the lamp fail...

The Steinitz ST1C (from late 80s) is wired same as the SN57 however. Its construction is very simple, like 8 components or so. The silicon present in it are a BT138 and a diac

In the SN57 is nothing more...

Well, all ignitors do not contain much components, the short range superimposed suffice with one resistor, one capacitor, one sidac and one pulse transformer, so 4 components in total, not counting the mechanical stuff to hold it all together (tghey even do not use PCB for interconnections)...
When they start to get more complex is, when some extra features are to be added, like restart timers (giving the lamp time to cool down before attempting another restart), EOL cycling suppression time out (after cumulative time of restart attempts reaches certain value, they stop, so the cycling lamp does only few cycles), some even contain an arc voltage monitor, so stop the reignition attempts after fewer cycles, while allow for more restarts after "phantom" extinguishes (caused by voltage dips, what extinct the arc, but are insufficient to reset the timer based ignitors). But even that mean only one or two extra chips (the most sophisticated use an microcontroller, so only one chip plus some output stage)

The ES50 and ST1C use the same ballast, its just flipped around. Same with the Shingot ignitor (the ignitor i have is not working, but the ELT/Shingot ballast that camewith it works fine with ES50)

The Fris Electromechanics one i found was blown up with a hole that melted from the side of the plastic can casing (showing remains of ~2w resistors inside), so that might be result of use with wrong ballast....

The ES50 and ST1C use the same ballast, its just flipped around. Same with the Shingot ignitor (the ignitor i have is not working, but the ELT/Shingot ballast that camewith it works fine with ES50)

I would have to see how they work.

But if you put the "5% tap" ballast together with the SN57, everything would work fine and if there would be no hot restart attempts, even nothing would be overloaded. And that situation could last easily for years, mainly when group relamping scheme is in place, so no lamp actually get into point of cycling.
Only when the lamp won't ignite, the ignition pulses may go up to 20kV with that setup (the voltage would be actually limited by flashovers on the socket or inside the lamp outer). And even this abuse would be in many cases survived by all the components for long time, without anyone noticing there is something wrong with the setup. Because with good lamp it would again resume normal operation.
Only when you would decide to run mass production with that, you would start to face unusual amount of field failures, where something really does fail due to the overvoltages.
So it is not question if it would work or not, but rather about reliability of that setup...

The Fris Electromechanics one i found was blown up with a hole that melted from the side of the plastic can casing (showing remains of ~2w resistors inside), so that might be result of use with wrong ballast....

I doubt such failure would be linked with the wrong ballast/ignitor combination. Most likely something failed within the ignitor (capacitor, switch element,...) and the resistor overheated only as a consequence. Even quite thin wall of the plastic box normally easily withstand 10's of kV before breaking through and the energy in these pulses is limited, so would not overload the resistor in such extent...