MKP 385

MKP Radial Potted Type

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Document Number: 28152

168

Revision: 13-Oct-08

APPLICATION NOTE AND LIMITING CONDITIONS

These capacitors are not suitable for mains applications as across-the-line capacitors without additional protection, as described

hereunder. These mains applications are strictly regulated in safety standards and therefore electromagnetic interference

suppression capacitors conforming the standards must be used.

To select the capacitor for a certain application, the following conditions must be checked:

divided by the applied voltage.

For all other pulses following equation must be fulfilled:

T is the pulse duration

4. The maximum component surface temperature rise must be lower than the limits (see figure max allowed component temp rise)

5. Since in circuits used at voltages over 280 V peak-to-peak the risk for an intrinsically active flammability after a capacitor

breakdown (short circuit) increases, it is recommended that the power to the component is limited to 100 times the values

mentioned in the table: “Heat conductivity”

6. When using these capacitors as across-the-line capacitor in the input filter for mains applications or as series connected with

an impedance to the mains the applicant must guarantee that the following conditions are fulfilled in any case (spikes and

surge voltages from the mains included).

Voltage Conditions for 6 Above

EXAMPLE

C = 4n7 1600 V used for the voltage signal shown in next figure.

The ambient temperature is 80 °C. In case of failure, the oscillation is blocked.

Checking the conditions:

1.

2. The peak-to-peak voltage 1000 V is lower than 2

√2 x 550 Vac = 1600 U

p-p

3. The voltage pulse slope dU/dt = 1000 V/4 µs = 250 V/µs. This is lower than 4000 V/µs (see specific reference data for each version)

4. The dissipated power is 35 mW as calculated with Fourier terms and typical tgd.

This is lower than 10 °C temperature rise at 80 °C, acc. figure.

5. Oscillation is blocked

6. Not applicable

Voltage signal:

2 ×⌠⎛dU⎞

2

⌡⎝ dt ⎠

× dt

< U

T

0

⎛dU⎞

⎝ dt

⎠

rated

ALLOWED VOLTAGES

Maximum continuous RMS voltage

Maximum temporary RMS-overvoltage (< 24 h)

Voltage

Time