[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Dan's ISSTCII help

Original poster: Skip Greiner <sgreiner@xxxxxxxxx>

After many fits and starts I finally fired up the ISSTCII.
I sequence the startup as follows: Turn on the pulse generator which is a remote box, Turn on the power to the driver board, lastly slowly increase the AC voltage to the IGBT power supply. Everything seemed to be going well. I had the IGBT DC bus voltage at about 100 volts and was varying the pulse width and prf controls about 10% up from minimum. The arcs at this point were well over 12" and the controls were functioning normally. After about a minute the arcs began to decrease in intensity and I immediately shut down the high voltage. Nevertheless the 37321 drivers fried. Right now it does not appear that the IGBTs fried but a full investigation can not be done until tomorrow. There are still normal drive pulses through to the 37321 sockets.
The +5, -15 and +15 supplies are all nominal. Drive pulses to the IGBTs were about 30v. I do not have a terminating resistor at present in the base feedback circuit.
My question to anyone with experience with Dan's unit...Has anyone experienced this failure at such a low voltage on the IGBTs and if so did you figure out what happened?
Thanks for any and all comments
Skip Greiner