Hello Mark,
I use almost this same circuit to send nanosecond pulses to an air-core coil to produce the RE effect. To me, the diode is a slightly misplaced flyback diode for the coil. The capacitor sets the pulse width. A RC damper is required because of the ringing. He's switching the low-side which tells me he's just turning the coil on and off, so just pulsing it over and over. Since he is using a DC-DC converter for HV, this tells me the current is very low, in the low mA range.
Dear Mr. Grumpy, I see we are on the same page as far as the over all concept goes, however I question the "the low mA range". Perhaps that is what you are seeing in your experiments. In my setup the primary pulse current reaches 101 Amps in about 70 micro seconds (at 3000 VDC) then quickly drops off. The re-charging current for the pulse capacitor is pretty high as well. It takes a full 5 seconds to recharge my capacitor bank with a power supply that is suppose to deliver 75 mA. Now our whole discussion revolves around the size of pulse capacitor used. Right now I'm using 8 each 5 uF 5kV capacitors connected in parallel. Now what the Gray team use and when is a whole different matter. Hand written notes on the motor patent for the EMA4-E1 listed 18 capacitors used (which implied 18 power supplies). Now all of those capacitors had to be stuffed in the black box on top of the motor, so they were not very big - if you assume the "transformer" was about the size of a can ignition coil. When Hackenburger swapped out these mechanical contact supplies for his transistor versions he had to add a big box onto the back of the motor for the EMA4-E2 version. I have no idea what size capacitor they were using in these applications. The Field notes that Ron Cole (not Marvin Cole) took from memory of the Converter Switching Element Tubes (CEST) that John Bedini posted shows large 5uF at 5 kV capacitors being used - in fact two of them, but this was a different technology altogether. Then in 1976 the EMA6 sported three each large dual HV capacitors (probably custom made at his favorite capacitor vendor). Now just how much capacitance can you stuff in a square can about the size of a large lunch box with commercial 1976 technology? I figure more than 5 uF. I would venture more around 50 uF. The surviving Kansas era motors used 50 uF capacitors (six each motor), But I was told by Nelson Schlaft that Gray also employed 100 uF capacitors as well. Anyway to work with these kinds of capacitors it requires some significant current if they are being pulsed a few times a second. I don't believe that all the current came from the DC-DC converter, maybe 10% of it. The rest came from a secret recycle circuit, but that is another post. Thank you for sharing your thoughts on this matter. Mark McKay
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Topic: Edwin Vincent Gray's conversion tube (Read 84638 times)
