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which type of capacitor for pulsed discharge
madires:
Another source: https://www.wima.de/en/our-product-range/pulse-capacitors/
StillTrying:
--- Quote from: LaserTazerPhaser on April 03, 2019, 02:53:58 pm ---A few simulations showed massive capacitor power dissipation at 100khz of ripple (1.8a peak) with only ~800mA of rms current.
--- End quote ---
How are you measuring the cap dissipation. If I measure the dissipation in a 0.1R serparate from the cap. the dissipation peaks are ~1.4kW, at around 1% duty (because 120A lasts only 2.5ms) that's ~14W average.
LaserTazerPhaser:
--- Quote from: StillTrying on April 03, 2019, 04:02:18 pm ---
--- Quote from: LaserTazerPhaser on April 03, 2019, 02:53:58 pm ---A few simulations showed massive capacitor power dissipation at 100khz of ripple (1.8a peak) with only ~800mA of rms current.
--- End quote ---
How are you measuring the cap dissipation. If I measure the dissipation in a 0.1R serparate from the cap. the dissipation peaks are ~1.4kW, at around 1% duty (because 120A lasts only 2.5ms) that's ~14W average.
--- End quote ---
The charging happens for ~1.1 - ~1.4seconds the 100khz charge period doesen't last 2.5mS and it repeats constantly after the capacitor is discharged.
T3sl4co1l:
You've provided no real information to make a decision on. What is the actual application? Circuit? Waveforms?
The PRF isn't meaningful; if it's fractional-Hz at the most gentle possible waveform, the only thing that won't do is possibly supercaps, and definitely not batteries (for full cycles, that is).
Tim
LaserTazerPhaser:
--- Quote from: tautech on April 03, 2019, 01:08:32 pm ---
--- Quote from: LaserTazerPhaser on April 03, 2019, 12:58:55 pm ---Are there any motor run caps above 100uF?
--- End quote ---
Never seen one more than 60 uF.
--- Quote ---Only the noname brands seem to go above 100uf which can be just motor start listed as motor run.
--- End quote ---
Yes and if you use a Start one in a Run application they let out the magic smoke. :scared:
Don't ask me how I know. :palm:
For just the few $ they are I'd try some of the Chinese Run caps and see how they perform. If they get too warm you might have to use proper Pulse rated caps at more cost.
I looked at getting some a while back for a sick electric fence I scored but the cost was something like $30 ea IIRC and I needed a couple.
Found a crowd in NZ that manufactured them for the few electric fence manufacturers we have here that export worldwide.
--- End quote ---
Was it a no name brand cap? Those probably have inadequate or no safety measures implemented.
--- Quote from: T3sl4co1l on April 04, 2019, 01:09:24 am ---You've provided no real information to make a decision on. What is the actual application? Circuit? Waveforms?
The PRF isn't meaningful; if it's fractional-Hz at the most gentle possible waveform, the only thing that won't do is possibly supercaps, and definitely not batteries (for full cycles, that is).
Tim
--- End quote ---
I was considering which capacitor is ideally suited for https://www.analog.com/en/products/lt3751.html massively powerful cap charger set to with 3.5amps peak 1.2amps rms at the secondary (shunt set to 9.8mR) it will run for hours and electrolytics might have disfavorable features for this application in which they cease to perform as a capacitor and in an ideal situation they have adequate safetey measures implemented. Its actually far more than 0.74Hz mentioned earlier with the 9.8mR shunt is nearly 1.9607Hz which puts even more of a load onto the capacitor. I just need >300v >32j per discharge cycle.
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