Kapanadze Cousin - DALLY FREE ENERGY

[Hoppy]

have you tried getting a discount for bulk ?

If your serious about just clipping the spikes try a version of this Voltage 'limiter' but don't dump it to zero volts, put it back in the system via a small value 'Resi' ok ((short it out to zero volts right or it will just over heat it and the mos fets)).
http://pdf.datasheetcatalog.com/datasheet/bytes/P6KE75A.pdf
look under 'transient voltage suppressors'

If Nick continues to use 200V rated mosfets, he will very likely need to use transorbs, especially when he removes the 24V lamp current limiting resistor and runs straight from his 24V PSU.

[stivep]

https://www.youtube.com/watch?v=16u6PEc8DUM&feature=youtu.be
Wesley

[NickZ]

   Itsu:
   Here is a scope shot of both expanded ringing signals, now, with a single 222 capacitor installed between each drain and source.
   The volts/div knobs set at blank (50v?), and sec/div is at .2us. 
   So the ringing signal between the two first peaks is now at 2.5MHz? Correct?
   The lower scope signal is the fet that was heating up previously. It is still showing a higher voltage than the upper (cool fet).
   
    I think that just with the 222 caps on, that has dropped the frequency by about 1/2.  The scope signal shows TWO divisions now, instead of the previous just ONE division. Highest voltages peaks now below 150v. Down from over 200v.
So, in the safe limits, hopefully?
   Let me know what you think, and also what resistor to place on the snubbers, also.  10 ohm resistors, maybe?
   This was done with me using two older fets, so that I could continue working on tuning these snubbers last night.
The new fets will be picked up later today.

[itsu]

Nick,


i think your blurry picture of your scope shows it is set at 2us/div. not 0.2us.
So this makes the time between the 2 top pulses 4us (2 div.) which is 250KHz.

So the ringing i see is of a 250Khz resonance signal, which is about 1/8th of your ringing signal without a cap (1.98Mhz), which is way to much as we need 1/2.

Concerning the expanded ringing screenshot, this is a strange signal and i also need to see the un-expanded signal as i now have no idea where/when this ringing
occurres, at turnon or turnoff time.


I think it is better to wait for your new scope / new MOSFETs so we can have high quality pictures of a good situation.


Thanks,  itsu

[ramset]

Sorry if this was already checked
But didn't Tinsel say that the ground "buss" is a common cause of this fuzzy view on older scopes ?

to repair ,  clean all the chassis grounds and reattach ?

apologies if this was already tried.