Document Number: 26018

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Revision: 01-Jul-10

155

MKP 1840 M

AC and Pulse Metallized Polypropylene Film Capacitors

MKP Radial Potted Type

Vishay Roederstein

MEASURING THE COMPONENT TEMPERATURE

A thermocouple must be attached to the capacitor body as in:

The temperature rise is given by

To avoid radiation or convection, the capacitor should be tested in a wind-free box.

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:

3. The voltage peak slope (dU/dt) shall not exceed the rated voltage pulse slope in an RC-circuit at rated voltage and without

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 graph max. allowed component

temperature 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

ALLOWED VOLTAGES

≤ 85 °C

≤ 100 °C

Maximum continuous RMS voltage

Maximum temperature RMS-overvoltage (< 24 h)

Thermocouple

2

dU

dt

--------





2

0

T



dt

U

Rdc

dU

dt

--------





rated

×

<

×

×