Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1307
| Posted: 10:30am 22 May 2019 |
It may not be as benign as it appears - I can say I was a bit scared at the quantum current jumps whilst slowly advancing the variac. Like 80ma to 220ma in less than 2V sometimes it just stayed there other times another 1 volt up would reduce current quite a bit and another volt up current back to another high value.
It was so unpredictable I did not push it over 135V. Maybe tomorrow I will get braver, put a perspex shield between me and the diodes and give it a heap more - they were only 1 amp diodes and I hate stuff going bang in my face.....
I like the low idling current of the 2 transformers - they must have a few extra turns to keep the flux a bit lower ?
Maybe all that circulating current can make FETs work real hard but this is not indicated on a supply current meter so you might have no idea that its actually occurring ? I also remember reading about transformer "hum" quality changing during idling etc. Maybe the flux does walk a bit under certain conditions ?
If at first you dont succeed, I suggest you avoid sky diving....
Cheers Mike