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Re: 48kW DRSSTC



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Steve,

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

1) The streamer current has a very high di/dt similar to a lightning strike. If the H-bridge layout was sloppy, L*di/dt could overvolt things. With a tight layout, the flywheel diodes will clamp these overvoltages down to the DC bus voltage.

You just keep loops small so little or no inductive coupling?


2) The streamer current is common mode. It came effectively from a capacitor whose other plate is RF ground, and it wants to go back to RF ground. If there is no nice AC path from the primary circuit back to RF ground, the streamer voltage will go flying through everywhere untill it "Finds" RF ground. That can couple nasty things through your GDTs etc. back into the driver.

Common mode from secondary coil's perspective. What about a hit on outside of primary, for example. Would this probably result in differential mode to some extent from drivers perspective?? and would this be an issue?? What is your AC path back to RF ground if the controller box is all grounded to green wire.


I used Faraday-shielded GDTs wound with miniature coax, and some capacitance between DC bus negative and the green wire ground. I also try to choose RF grounds that are fairly well related to the green wire ground. (Indoor coiling is good here because any metal nearby should be connected to the green wire quite directly.)

Not sure what GDT is. Is the coax shield part of the protection and what is it grounded to?? For high power outdoor operation, is your RF ground still a stake in the ground?? and do you also connect the green wire to RF gound??

Thankyou for your insight,

Gerry R.