Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx> Hi Justin,Resonant charging can occur with non NST sources as well. The inductive ballasted PIG, for instance, can also resonate with the tank cap. The mechanism is essentially the same. One real difference is when you get into the higher power levels these non NST trannies can provide, it becomes more expensive to run LTR valued caps. Many use smaller than resonant (STR) caps but this requires a much higher breakrate to keep the voltages reasonable. Another potential problem is when you run 120 BPS synchronous with a PIG and use a tank cap value of 2.8*Cres, the bang becomes much larger and the coil may not take it (racing sparks may occur). I will find out in time how significant this may be since I am planning a 5KVA PIG with SRSG of 120 bps.
Another difference, is the robustness of the transformer. An overvolt condition will kill a NST long before it will kill a PIG. The best way to evaluate your particular configuration if using a ARSG is to SPICE it. If you run a static gap I believe the analysis would be the same as used for a NST. If you use a SRSG at 120 bps, you will indeed want to use a 2.8*Cres value of cap. Smaller caps will give you larger voltages and a overvolt condition can occur. If you use a SRSG at 240 bps and less than 2.8*Cres, a SPICE simulation should probably be done.
Gerry R.
Original poster: Justin <rocketfuel@xxxxxxxxxxxxx> My question is regarding primary cap sizing when using a non-NST power supply. I know with the NSTs we have to worry about creating a resonant condition between the tank cap and the secondary windings of the NST. What I am wonder is: does this problem not exist with non-magnetically limited transformers? How does one determine best tank cap size when the LTR condition no longer exists? Obviously it needs to be matched to the primary L to resonate at the secondary circuit's frequency, but what about inductive kick from the ballast overvolting the tank cap? It may be helpful to know that I am planning to use a sucker static gap with this coil. Thanks for any suggestions and comments! Justin in Austin