Peter, you were right. The problem is not in the frequency.
It turned out that the problem is in too large capacitance of the booster side cap. At first I was using a voltage quadrupler with four 100uF 450V caps. I could go up to 1000V on the booster side, but the if the discharge frequency was set to 25Hz (the minimum that I need), then there was an ordinary spark on every discharge, but the intensified spark appeared only on every fourth or fifth discharge. I could ho up with the frequency till 100Hz, but the intensified spark appeared only some 4-5 times a second. So I decreased the booster side capacity. I replaced the quadrupler with a bridge rectifier that charges up a 0.82uF 1000V cap through a light bulb. When I turned the variac to full voltage, there was about 300V in the cap. I turned the primary side ON at 100Hz frequency and there was an intensified spark on every discharge. But the effect was rather small, so I doubled the capacity. This made a bigger plasma and was still capable to handle the 100Hz. I increased the capacitance by 0.82uF on each test and the intensified spark seemed to become brighter and louder with each test. I got the capacity up to 6.56 uF, but the spark was the same as when using only about 4uF. So that must be the right capacity. Unfortunately I have only six of those polypropylene caps so I can not make a voltage doubler keeping the same capacity. I already tried that using two 2.46uF caps for the doubler, each made out of three 0.82uF caps in parallel, the spark was almost the same, maybe a little brighter. So I guess that if I increased the voltage keeping the same capacity, I could get bigger blasts. Also I noticed that the bigger capacity on the booster side, the greater also the power consumption from the variac. At capacitance of 6.56 uF, the power consumption from the variac was about 35W. Also, the more power we feed into the spark from the LV side, the hotter the spark plug electrodes become.
Here is a small video with the intensified spark about 50Hz:
YouTube - test8
Now I need to get some more caps and try the same capacity with a voltage doubler.
Thanks,
Jetijs
It turned out that the problem is in too large capacitance of the booster side cap. At first I was using a voltage quadrupler with four 100uF 450V caps. I could go up to 1000V on the booster side, but the if the discharge frequency was set to 25Hz (the minimum that I need), then there was an ordinary spark on every discharge, but the intensified spark appeared only on every fourth or fifth discharge. I could ho up with the frequency till 100Hz, but the intensified spark appeared only some 4-5 times a second. So I decreased the booster side capacity. I replaced the quadrupler with a bridge rectifier that charges up a 0.82uF 1000V cap through a light bulb. When I turned the variac to full voltage, there was about 300V in the cap. I turned the primary side ON at 100Hz frequency and there was an intensified spark on every discharge. But the effect was rather small, so I doubled the capacity. This made a bigger plasma and was still capable to handle the 100Hz. I increased the capacitance by 0.82uF on each test and the intensified spark seemed to become brighter and louder with each test. I got the capacity up to 6.56 uF, but the spark was the same as when using only about 4uF. So that must be the right capacity. Unfortunately I have only six of those polypropylene caps so I can not make a voltage doubler keeping the same capacity. I already tried that using two 2.46uF caps for the doubler, each made out of three 0.82uF caps in parallel, the spark was almost the same, maybe a little brighter. So I guess that if I increased the voltage keeping the same capacity, I could get bigger blasts. Also I noticed that the bigger capacity on the booster side, the greater also the power consumption from the variac. At capacitance of 6.56 uF, the power consumption from the variac was about 35W. Also, the more power we feed into the spark from the LV side, the hotter the spark plug electrodes become.
Here is a small video with the intensified spark about 50Hz:
YouTube - test8
Now I need to get some more caps and try the same capacity with a voltage doubler.
Thanks,
Jetijs
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