Converter In-Rush Thermistors etc, UPDATE -4
UPDATE on 17 Nov, Update 2 on 22 Nov, Update 3 on 16 Jan 14, Update 4 on 19 Oct 14. --------------- In a recent thread there was mention of how you can wreck your gizmo (in my case a converter) ...
Forum Discussion
In the lesson they calculate that minimum R is 5.7 ohm, then they recommend their 5 ohm thermistor. In the other lesson, Min R was 1.2 so they say use the 1R thermistor.
"minimum R" does not appear to mean what it says?
In the protect the transformer version, they say in rush on the scope is 564a but the transformer can only take 1/4 of that so they want a limit of 141. They then use line voltage 120/141 to get 1.2 for min R
That one has 2300uF of capacitors
In the protect the capacitors version with 5000uF of caps they don't say what scope in rush is but say limit is 1/3 of it and use 30a (so in rush was only 90a? Then they somehow turn 110 line voltage into 171volts and divide that by 30 to get 5.7 for min R.
So I don't know my scope in rush if it is in the order of 564a or 90a.
I have 2400uF of caps and a 25a diode bridge good to 60a that the thermistor is ahead of.
I get more confused every time I go through the two lessons and read back in this thread. We have the thread dispute between Salvo and the rest on using less or more R too, which may be linked to the apparent (to me, being confused) contradictions in the above two lesson examples?
Stepping back, I do know the diode bridge and caps are still fine even though the thermistors have blown, including 2.5R and 5R thermistors, and the converter will run with either R size unless it gets a hot restart.
It seems like we are almost there to get the R, but the answer evaporates at the last minute. :(
"minimum R" does not appear to mean what it says?
In the protect the transformer version, they say in rush on the scope is 564a but the transformer can only take 1/4 of that so they want a limit of 141. They then use line voltage 120/141 to get 1.2 for min R
That one has 2300uF of capacitors
In the protect the capacitors version with 5000uF of caps they don't say what scope in rush is but say limit is 1/3 of it and use 30a (so in rush was only 90a? Then they somehow turn 110 line voltage into 171volts and divide that by 30 to get 5.7 for min R.
So I don't know my scope in rush if it is in the order of 564a or 90a.
I have 2400uF of caps and a 25a diode bridge good to 60a that the thermistor is ahead of.
I get more confused every time I go through the two lessons and read back in this thread. We have the thread dispute between Salvo and the rest on using less or more R too, which may be linked to the apparent (to me, being confused) contradictions in the above two lesson examples?
Stepping back, I do know the diode bridge and caps are still fine even though the thermistors have blown, including 2.5R and 5R thermistors, and the converter will run with either R size unless it gets a hot restart.
It seems like we are almost there to get the R, but the answer evaporates at the last minute. :(
