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Optical trigger Tuning

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Yandersen

Mon Jan 28 2013, 06:46AM

Registered Member #6944 Joined: Fri Sept 28 2012, 04:54PM
Location: Canada
Posts: 340

Looks like voltage divider to control the voltage on caps.

ZakWolf

Mon Jan 28 2013, 07:24AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
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oh yeah that's what i thought just making sure, I just drew up the pcb for the optical/ charging reg. circuit. I am still at a loss as to why the diodes died...

I have the + output of the bridge rectifier going to two separate diodes going to each + cap terminal... If i fire only the first stage only while leaving the second stage charged(ie. disabling the trigger circuit) both banks will fire when only the first one should and the diodes no longer limit the direction of flow.

I tested this with many sets of diodes :\

Yandersen

Mon Jan 28 2013, 03:17PM

Registered Member #6944 Joined: Fri Sept 28 2012, 04:54PM
Location: Canada
Posts: 340

Try doubled voltage rating (put 2 diodes in series) - during the shot caps may get repolarized.
And where do you control the voltage? Must be like shown - on one of the caps, NOT after the charger's output diode.

ZakWolf

Tue Jan 29 2013, 06:21PM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
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Posts: 608

Yandersen wrote ...

Try doubled voltage rating (put 2 diodes in series) - during the shot caps may get repolarized.
And where do you control the voltage? Must be like shown - on one of the caps, NOT after the charger's output diode.

Could you elaborate a little for me

Yandersen

Tue Jan 29 2013, 11:27PM

Registered Member #6944 Joined: Fri Sept 28 2012, 04:54PM
Location: Canada
Posts: 340

You don't know how to put two diodes in series?! Replace each of your doides (ones separating the banks) with some double-voltage rated. Or simply replace each one with a couple series connected to get doubled voltage hold capability.
Maybe you need speedy diodes - not a regular rectifiers.

ZakWolf

Wed Jan 30 2013, 01:22AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
Location:
Posts: 608

Yandersen wrote ...

You don't know how to put two diodes in series?! Replace each of your doides (ones separating the banks) with some double-voltage rated. Or simply replace each one with a couple series connected to get doubled voltage hold capability.
Maybe you need speedy diodes - not a regular rectifiers.

Ha... I know what series means i was just confused by

Yandersen wrote ...
on one of the caps, NOT after the charger's output diode

what do you mean by not after the output diodes?

It was my understanding uf4007's are reflectively fast, and is the voltage really spiking that high during discharge? So could i put 2 in series to give me 2kv at 1 amp

Yandersen

Wed Jan 30 2013, 11:46AM

Registered Member #6944 Joined: Fri Sept 28 2012, 04:54PM
Location: Canada
Posts: 340

If doubling the voltage of diodes will not help, show us your charger circuit. I guess there is a small cap at the output, then a switch, and diodes to each cap at the bank, right? After you discharge your caps, you turn the charging switch on, the voltage between the output cap and the bank caps is burning your diodes due to unlimited current - it might be another reason. I'm not a telepath, so I have no idea of what and how is connected in your setup. If you can't figure the problem out by yourself, then give us some info about what you are doing, OK? Otherwise how can we help you?

ZakWolf

Wed Jan 30 2013, 04:57PM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
Location:
Posts: 608

I will supply more details for you soon

ZakWolf

Sun Feb 03 2013, 09:17PM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
Location:
Posts: 608

Sorry this took so long, this is the current setup. Sorry i drew it by hand.

DerAlbi

Mon Feb 04 2013, 01:39AM

Registered Member #2906 Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727

If you discharge your Caps, you basically short circuit them. So you take your drawing and wipeout the Caps and replace it with a "wire".
Can you imagine where the current flows? Can any of your Charger-Sources deliver more than 1A if the Caps are shorted? If yes.... well....

You have successfully "disconnected" the caps from each other, so one will not recharge the other. However you have not disconnected the charger circuit. E.g. is you have the Mains connected to the Bridgerectifier.... well... ouch^^
This would take a SCR, Mosfet, Transistor or IGBT at the common ground-connection at the caps. I would recommend the SCR - you switch your charger on, fire the SCR and it shuts off automatically after the caps are charged...

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