nahrada kondiku 0,68u/275/X2 za 1u/275/X2 .. bylo lednice ...

[Jan Waclawek]

>No dobre, takze nas po vlne kapacititidy
>elektrolyticko-vysychaco-nafukovacieho typu caka vlna kapacititidy
>foliovo-prestrielaneho typu?


No takze som tomu venoval 10 minut na gugli... a zaver je, ze nie je X2 ako
X2.

V principe X2 musi byt "samoopravny" t.j. konstrukcia musi zabezpecit, ze
po prieraze nasledkom napatovej spicky nevznikne skrat (no a samozrejme ze
sa neprerazi do nejakeho napatia). Nic to vsak nevravi o kapacite po tom
prieraze.

Z https://en.wikipedia.org/wiki/Film_capacitor :
A non-catastrophic failure mode in this application is due to the corona
effect: the air enclosed in the winding element becomes ionized and
consequently more conductive, allowing partial discharges on the
metallized surface of the film, which causes local vaporization of the
metallization. This occurs repeatedly, and can cause significant loss of
capacitance (C-decay) over one or two years. International standard
IEC60384-14 specifies a limit of 10% C-decay per 1,000 test hours (41 days
of permanent connection).[65] Some capacitors are designed to minimise
this effect. One method, at the expense of increased size and cost, is for
a capacitor operating at 200-240 VAC to consist internally of two parts in
series, each at a voltage of 100-120 VAC, insufficient to cause
ionisation. Manufacturers also adopt cheaper and smaller construction
intended to avoid corona effect without series-connected sections, for
example minimising enclosed air.

Wikipedia sa odkazuje na Vishay ktori maju rad specificky urceny ako
zrazacie kondenzatory (F1772 - ako bolo spomenute, su to interne dva kondy
zapojene seriovo). Takze sa mozno oplati venovat par minut hladaniu typu
na tento ucel navrhnutemu a mozno aj tych par korun bo urcite budu
drahsie, ak len teda nemate pravidelnu opravu takychto veci ako konicek...
;-)


wek