CDE Cornell Dubilier • 1661 E. Rodney French Blvd. • New Bedford, MA 02744 • Phone: (508)996-8561 • Fax: (508)996-3830

Expected Lifetime Predictions

Expected Lifetime vs Hot Spot Temperature and Applied DC Voltage

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1.6

1000

10000

100000

1000000

Expected Lifetime (h)

50ºC

60ºC

70ºC

85ºC

C (µF)

ESR (mΩ)

f (kHz)

I (A

rms)

T

A (°C)

T

C (°C)

Θ (°C/W)

Θ

CA (°C/W)

Θ

CC (°C/W)

v (m/s)

V

A (VDC)

V

R (VDC)

Determine ESR at Operating Frequency

Use the 10 kHz ESR from the ratings tables.

For operation below 10 kHz, the ESR will need to be adjusted using the following

equation: ESR - 31.83/(10C) + 31.83/(fC).

Determine Thermal Resistance at Operating Frequency and Air Flow

Compute Θ = Θ

CC + ΘCA. In the ratings tables, ΘCA is for still air. For v = 0 to 5 m/s,

multiply Θ

CA by [(5 + 17.6(0.1

0.66

)) / (5 + 17.6(v + 0.1)0.66)]

Determine Expected Lifetime

Look up Expected Lifetime on the graph using V

A/VR and TC = TA + I

2

(ESR/1000) Θ

The maximum allowed temperature rise is 40 °C and the maximum allowed core

temperature is 95 °C.

Capacitance:

Equivalent Series Resistance:

Frequency:

Ripple Current:

Ambient Temperature:

Core Temperature:

Total Thermal Resistance:

Thermal Resistance case-to-ambient:

Thermal Resistance core-to-case:

Airflow Speed:

Applied Voltage:

Rated Voltage:

Type 944L Low Inductance DC Link Capacitors

For Fast-switching Inverter Applications