FFLC31MA4427 Datasheet, PDF (4/9 Pages) AVX Corporation – Medium Power Film Capacitors

Medium Power Film Capacitors
FFLC
MTBF CALCULATION
The failure rate λB depends on hot spot temperature θHS and charge ratio ρ.
ρ = Uw/Un
( ^{( )})
in failures/hour
GENERAL FAILURE RATE
λ=λB x πQ x πB x πE failures/hour • πQ, πB and πE see following tables
Qualification
Product qualified on IEC61071
and internal qualification
Product qualified on IEC61071
Product answering on
another norm
Product without qualification
Qualification
factor πQ
1
2
5
15
Environment
On ground (good conditions)
On ground (fixed materials)
On ground (on board)
On ship
On plane
Environment
factor πE
1
2
4
9
15
Environment
Favorable
Unfavourable
Environment
factor πB
1
5
MEAN TIME BETWEEN FAILURE (MTBF)
MTBF = 1/λ hours
SURVIVAL FUNCTION
N = N0 x exp (-λt)
N is the number of pieces still working after t hours.
N0 is the number of pieces at the origin (t = 0)
FAILURE MODE
Main failure mode due to AVX’s Controlled Self-Healing Technology is only losses of capacitance. Thanks to Controlled
Self-Healing solution to interrupt self-healing process in order to prevent avalanche effect due to polypropylene molecular
cracking producing gas and potential explosion in confined box for none Controlled Self-Healing capacitors.
JUNE 2015 ■ 45