I am trying to prototype a bridge rectifier. It looks right to me, but when I plugged it in, I got arcing in the rectifier tubes.
The power transformer has two B+ leads, a 300-0-300 and a tap off that for 250-0-250. They share the center tap, in other words.
Previously, there was a full-wave tube rectifier for each of these windings, which worked great. The center tap was grounded to the first filter cap.
I am trying to make the 300-0-300 a hybrid bridge rectifier, so that I can unground the centertap and use it to provide a half-B+ screen supply. I wired two 1n4007 with their cathodes at each plate of the 5u4, and their anodes at ground. I ungrounded the center tap. I left the 250-0-250 winding disconnected until I put a bridge there too. I plugged it in, and got arcs in the tube and then it blew the reset breaker! Resistance from Cathode of 5u4 to ground is infinity, resistance from anode of 5u4 to ground is infinity, resistance from ground to anodes is the voltage drop of the SS diodes. I am fairly sure there are no B+ leaks to ground, resistances look good, so do filter caps. Anyone have any experience with hybrid bridges? Are my tubes coming up too slow?
The power transformer has two B+ leads, a 300-0-300 and a tap off that for 250-0-250. They share the center tap, in other words.
Previously, there was a full-wave tube rectifier for each of these windings, which worked great. The center tap was grounded to the first filter cap.
I am trying to make the 300-0-300 a hybrid bridge rectifier, so that I can unground the centertap and use it to provide a half-B+ screen supply. I wired two 1n4007 with their cathodes at each plate of the 5u4, and their anodes at ground. I ungrounded the center tap. I left the 250-0-250 winding disconnected until I put a bridge there too. I plugged it in, and got arcs in the tube and then it blew the reset breaker! Resistance from Cathode of 5u4 to ground is infinity, resistance from anode of 5u4 to ground is infinity, resistance from ground to anodes is the voltage drop of the SS diodes. I am fairly sure there are no B+ leaks to ground, resistances look good, so do filter caps. Anyone have any experience with hybrid bridges? Are my tubes coming up too slow?
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