grizedale
Advanced Member level 3
I hope its ok to write about some concerns I have about our usage of the ZS1052 SUL(H) V02 trigger transformer for 1 to 15W xenon flash tubes.
What are the dangers of triggering with “first pulse negative” if the tube requires “first pulse positive”?
Also, basically, I am wondering if there is a version of this trigger transformer with the primary coil phased the opposite way?
-This is due to the fact that some of our xenon tube datasheets specify a positive secondary trigger pulse and some specify a negative secondary trigger pulse.
In all cases, we have the trigger transformer set up as in the following schematic, and the secondary waveform is shown here too………………….
Schematic of trigger transformer circuit using ZS1052 SUL(H) V02:
https://i46.tinypic.com/300y5gy.jpg
(we are actually using a thyristor instead of a FET, and turn it on for 10us)
Secondary pulse from above circuit showing first pulse negative:
https://i45.tinypic.com/11gt92q.jpg
…as you can see, we have it set up in “first pulse negative” configuration.
I noticed that the BG0625 DDS8 xenon tube (which we use) has a quoted “+6KV” secondary trigger voltage.
…may I ask if this means that the first pulse is required to be positive?
I am asking because our setup has first pulse negative, and this is of some concern for us.
Could I also please ask if there exist trigger transformers like the ZS1052 SUL(H) V02 but with the primary phased the other way?, ..i.e. so we get a first pulse positive waveform
- - - - - - - - - - - - - -
Incidentally, supposing we really did use a FET instead of a thyristor in the above schematic, -then the turn off of a FET is much more sudden than that of a thyristor, and a sharp , very high voltage secondary spike can sometimes occur as the following schematic and waveform show……….
Schematic of trigger circuitry.
https://i50.tinypic.com/33u7rrl.jpg
Secondary waveform of the above.
https://i49.tinypic.com/34gubde.jpg
…..and you can see that this solitary , very high voltage spike is positive.
-Supposing our xenon tube requires “first pulse negative” tirggering……then would the fact that the very high pulse in the above waveform is positive be damaging to this tube?….
Another question (sorry to ask so many), …….supposing that a xenon tube is spec’d for “first pulse positive” use……..but we trigger it with “first pulse negative” waveform that has a very high positive spike like the above waveform, then does this make up for the fact that the first pulse was not positive?
(By the way, you can see that the above very high voltage positive spike is caused because the FET turns off at that moment when the primary current is running through the FET from drain to source [as opposed to the other way, where it can also flow through the FET’s anti-parallel diode]…………so it’s the current flow in the primary inductance being broken which ultimately causes the high voltage spike)
Anyway, sorry for the length of this post
What are the dangers of triggering with “first pulse negative” if the tube requires “first pulse positive”?
Also, basically, I am wondering if there is a version of this trigger transformer with the primary coil phased the opposite way?
-This is due to the fact that some of our xenon tube datasheets specify a positive secondary trigger pulse and some specify a negative secondary trigger pulse.
In all cases, we have the trigger transformer set up as in the following schematic, and the secondary waveform is shown here too………………….
Schematic of trigger transformer circuit using ZS1052 SUL(H) V02:
https://i46.tinypic.com/300y5gy.jpg
(we are actually using a thyristor instead of a FET, and turn it on for 10us)
Secondary pulse from above circuit showing first pulse negative:
https://i45.tinypic.com/11gt92q.jpg
…as you can see, we have it set up in “first pulse negative” configuration.
I noticed that the BG0625 DDS8 xenon tube (which we use) has a quoted “+6KV” secondary trigger voltage.
…may I ask if this means that the first pulse is required to be positive?
I am asking because our setup has first pulse negative, and this is of some concern for us.
Could I also please ask if there exist trigger transformers like the ZS1052 SUL(H) V02 but with the primary phased the other way?, ..i.e. so we get a first pulse positive waveform
- - - - - - - - - - - - - -
Incidentally, supposing we really did use a FET instead of a thyristor in the above schematic, -then the turn off of a FET is much more sudden than that of a thyristor, and a sharp , very high voltage secondary spike can sometimes occur as the following schematic and waveform show……….
Schematic of trigger circuitry.
https://i50.tinypic.com/33u7rrl.jpg
Secondary waveform of the above.
https://i49.tinypic.com/34gubde.jpg
…..and you can see that this solitary , very high voltage spike is positive.
-Supposing our xenon tube requires “first pulse negative” tirggering……then would the fact that the very high pulse in the above waveform is positive be damaging to this tube?….
Another question (sorry to ask so many), …….supposing that a xenon tube is spec’d for “first pulse positive” use……..but we trigger it with “first pulse negative” waveform that has a very high positive spike like the above waveform, then does this make up for the fact that the first pulse was not positive?
(By the way, you can see that the above very high voltage positive spike is caused because the FET turns off at that moment when the primary current is running through the FET from drain to source [as opposed to the other way, where it can also flow through the FET’s anti-parallel diode]…………so it’s the current flow in the primary inductance being broken which ultimately causes the high voltage spike)
Anyway, sorry for the length of this post
