947D Datasheet, PDF (6/9 Pages) Cornell Dubilier Electronics – High Current, High Capacitance for Inverter Applications

Type 947D Polypropylene, High Energy Density, DC Link Capacitors
High Current, High Capacitance for Inverter Applications
Expected Lifetime Predictions
Capacitance: C (µF)
Equivalent Series Resistance: ESR (mΩ)
Frequency: f (kHz)
Ripple Current: I (A_rms)
Ambient Temperature: T_A (°C)
Core Temperature: T_C (°C)
Total Thermal Resistance: Θ (°C/W)
Thermal Resistance case-to-ambient: Θ_CA (°C/W)
Thermal Resistance core-to-case: Θ_CC (°C/W)
Airflow Speed: v (m/s)
Applied Voltage: V_A (V_DC)
Rated Voltage: V_R (V_DC)
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).
Compute Θ = ΘCC + ΘCA. In the ratings tables, ΘCA is for still air. For moving
air use the capacitor surface area A and airflow speed v to calculate
θca = 1 ⁄[A(5+17(v+0.1)0.66)].
Look up Expected Lifetime on the graph using V_A/V_R and T_C = T_A + I² (ESR/1000) Θ
The maximum allowed temperature rise is 40 °C and the maximum allowed core temperature is 95 °C.
Expected Lifetime vs Core Temperature and Applied DC Voltage
1.4
1.3
50 ºC
1.2
60 ºC
1.1
70 ºC
1
0.9
85 ºC
0.8
1000
10000
100000
Expected Lifetime (h)
1000000
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