The amount of current is divided into four for a 4-parallel resistor arrangement. At least that's what the numbers are telling me.
I have yet to try that intentionally. Time to put out some wire wounds.
your amp doesn't determine timing
As noted above I think it wouldn't be hard to have a board that could accommodate parallel resistors or series NTCs (2).
As noted above I think it wouldn't be hard to have a board that could accommodate parallel resistors or series NTCs (2).
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yes, so why belabor the resistor value? series/parallel, who cares? as long as the circuit do the job...
i have built a lot of amps without even using a soft starter, i used a big current rated switch, rated for 16 amperes....
Andrew has pointed out that a couple of NTCs in series may be preferred/needed in some situations
Agreed. I also suspect there's no need in most situations for there to be two in series - just have the switch flick before the rating of the NTC is exceeded.
I'm still interested in why Andrew is pressing for series rather than parallel resistors...the desire to use NTCs rather than resistors doesn't demand the resistors be in series also.
I need to read the passages Mark alluded to in post #176
I'm still interested in why Andrew is pressing for series rather than parallel resistors...the desire to use NTCs rather than resistors doesn't demand the resistors be in series also.
I need to read the passages Mark alluded to in post #176
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Perhaps but many years ago, I built an F1 with crazy amounts of capacitance and used a single CL-60 in the primary. The slow blow fuse kept on blowing up upon power up so we end up using two CL-60 in series.
Me too. In the hopes of making a better, easy to build soft start.
I did make one with comparators, timers, etc but it has proven to be far more complicated and I assume it would be also for someone else to build. I think Andrew has commented before regarding control of the timing which will be better having it's own "real" timer. But KISS principle tend to be against it.
This soft start has so far worked with amps I use everyday, I also use an early prototype on my cnc psu because of the large toroid and amount of capacitance I used.
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Yet the circuit has a readily controllable "timer" - set to taste using C2 and/or the current limiting LED resistor.
I note that Self says to NOT place resistors in series: "with a parallel connection, if one of the resistors fails open-circuit (which is by far the most likely mode), the inrush system will probably keep working satisfactorily."
I note that Self says to NOT place resistors in series: "with a parallel connection, if one of the resistors fails open-circuit (which is by far the most likely mode), the inrush system will probably keep working satisfactorily."
