An alternative MOT power supply circuit as proposed by coiler Steve Young. Click here to view the schematic.

The pasted-in text below is the actual e-mail exchange between me and Steve regarding his improved MOT power supply incorporating an inductive charging reactor to boost performance. I'll let the correspondence speak for itself (Greg)


S & J Young < wrote:

Hi Greg,

The attachment is a dual MOT voltage doubler and charging reactor powering a conventional asychronous RSG TC. It is significantly more efficient then the dual MOT tripler powered SPDT RSG circuit. The only downside is that the RSG BPS must be at least 400 BPS to avoid RSG power arcing. This setup produces 53 inch streamers between dual 4 x 23 inch twin coils with about 1,400Watts DC. --Steve Young

Original Message ----- From: "Gregory Hunter" <> To: "S & J Young" <> Sent: Sunday, October 14, 2001 10:13 AM Subject: Re: Another MOT powered TC Circuit

Hi Steve,

What advantage are you claiming for this circuit? The dual MOT/voltage doubler/filter circuit already provides about 12kvdc. I know something of charging chokes, I've worked with them in radar power supplies before. Does the reactor in your circuit provide higher voltage? Can you quantify the performance advantage (at least in general terms) of this circuit?

Thx, Greg


Greg Hunter asked some good questions about my DC charging reactor setup which I thought I should answer on the list. Greg Leyh may want to add some further advantages. Greg, 1) The charging reactor does indeed charge the tank cap to about twice the power supply voltage. This is good for lower voltage higher current supplies such as those using MOTs. The dual MOT supply only puts out about 12 KV DC when unloaded. When it is supplying a few hundred ma, it drops down to 8-9 KV. 2) It also allows one to put a RSG directly across the DC power supply. Without the choke, the RSG will just power-arc. With the choke, if the RSG break rate is high enough (electrode dwell time low enough), it allows the RSG to quench the spark before the choke saturates and runs the current way up (initiating the power arc). 3) Final advantage is allowing one to use a non-synchronous higher break rate so that smaller tank capacitance can be used and one can still run a lot of power into the primary (power is directly proportional to break rate). 400 or 500 BPS has a nice "musical" quality to the streamers. 4) Bonus - it's a bit different and fun to experiment with. It is the scheme Greg Leyh uses with his monster coils. That said, my next adventure will be oven style doublers like yours (sine wave 0 to 12 KV output) married to a TSG. It's the only way I can think of that one can use a voltage multiplied MOT supply with a TSG. As I reported before, I tried that with the SPDT gap (two TSG firing alternately) and could not keep them from both firing at once which was a disaster. I haven't tried a TSG with the charging reactor MOT doubler setup, but I don't see how it wouldn't power arc unless there was a tremendous blast of air to blow out the arc. Comments regarding this from list would be welcomed. --Steve -----