9

ELECTROLYTIC ALUMINUM CAPACITORS

Revision 01/19

www.exxelia.com

Tel : + 33 (0)2 40 01 26 51

ELECTROLYTIC ALUMINUM CAPACITORS

9

Revision 01/19

www.exxelia.com

Tel : + 33 (0)2 40 01 26 51

r.m.s. value according to current waveform.

6.4.3. Dissipated power versus case dimension

Forcalculationsofripplecurrents,consideringaninternaltemperature

rise of 10°C

P = ESR.I ²

P = Dissipated power (mW)

( i - a = 10°C)

ESR: Equivalent series resistance (100 Hz 20°C)

I: Ripple current (r.m.s. value at 100 Hz)

For different frequencies from 100 Hz, I must be multiplied by the

factor F, according to above chart.:

6.4.4. Thermal resistance Rth and air cooling

Rth is static thermal resistance (without cooling) between capacitor

central hot spot and ambient temperature measured at a distance of

one capacitor diameter

Forced or not cooling air can lead to a significant decrease of these

values.

Consequently, r.m.s. ripple current can be increased as a function of air

cooling speed:

Ø mm

(inches)

≤ 0,5 m/s

1 m/s

2 m/s

3 m/s

≥ 4 m/s

66 - 90

I~

1,1 I~

1,2 I~

1,25 I~

1,3 I~

36 - 51

I~

1,2 I~

1,4 I~

1,45 I~

1,5 I~

This parameter shall be applied to one capacitor alone.

For capacitors in bank, ambient temperature must be strictly equal

around all capacitors.

6.4.5. Quality guaranty

We guarantee products manufactured during 2 years from the data of

shipment against defaults of material and assembly.

This guaranty can be involved by the buyer only if our products are

used within normal conditions, always according to the state of the

art and taking in account storage conditions.

The equipment design should take into consideration possible failures

of our capacitors and related effects in order to avoid them.

Guaranty is not applicable for damages occurred by surge voltage,

irregular use, polarity inversion or maintenance default.

Guaranty is exclusively limited to the replacement of individual

defective capacitors within the terms of delivery. This rule applied to

all cases and particularly to any further consequence of failures.

6.4.6. Reliability

Failure rate:

FR =

Number of components tested x test duration

Number of failures

Failure rate is measured in FIT (failure in time = 10–9 / hour).

The failure rate is set up during the life time of the capacitor (phase II)

I. Early failure phase (generally excluded during ageing process).

II. Operational life time of the capacitors

III. End of life

Function

Mean value

R.m.s. value

A (t0/T)

A

gt0/T

A (t1/T)

A

g2t1/3T

A/2 (t0/T)

A

gt0/3T

Function

Mean value

R.m.s. value

A /2

A

g3

2A/ (t0/T)

A

gt0/2T

A/2 (t0/T)

A

gt0/3T

Function

Mean value

R.m.s. value

2A/

A /

g2

A /2

A /

g3

0

A

General technical data