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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.