At 02:05 PM 2/3/00 +0000, Peter Chadwick wrote:
>Rich says:
>
> (snip) I don't know the repetitive peak current rating
> >>of those diodes
>
>
> >200 amperes
>
>Are you sure that is the repetitive peak, Rich? The transient peak not
>exceeding so many milliseconds, yes, but repetitive peak? Sounds very high.
>
>73
>
>Peter G3RZP
As per my old Motorola Silicon Rectifier Manual,
Max NON-REPETITIVE surge current (one cycle) is 200 amps
Max NON-REPETITIVE surge current (100 cycles) is 50 amps
From the same manual, charts from O. H. Schrade, Proc. IRE, vol. 31, p.
356, 1943, suggest that the RMS single diode current in my supply at the
time of failure was 2.97 amps!
Of course, I didn't use this chart to select the diodes. Instead I used a
table on the next page which stated that the peak diode current was 8x the
average. This would have been well within the capabilities of the diodes.
Since, when initially testing, I ran full loads of about 2.5 times the
current run at time of failure, I have to believe that maybe it wasn't
current that did them in. Then again, maybe so.
What I would really like to know is if there is anyone out there who has
successfully run 1N5408 diode in a bridge with a 32 mfd cap filter, 11 ohm
secondary resistance and 2 amps of current.
Still wondering,
Larry - W7IUV
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