Document Number: 28124

www.vishay.com

Revision: 19-Mar-13

207

MMKP 383

AC and Pulse Double Metallized Polypropylene

Film Capacitors MMKP Radial Potted Type

Vishay BCcomponents

This document is subject to change without notice.

Not Recommended for New Design, Use New MMKP383

POWER DISSIPATION AND MAXIMUM COMPONENT TEMPERATURE RISE

The power dissipation must be limited in order not to exceed the maximum allowed component temperature rise as a function of

the free air ambient temperature.

The power dissipation can be calculated according type detail specification “HQN-384-01/101: Technical Information Film

Capacitors”.

The component temperature rise (

T) can be measured (see section “Measuring the component temperature” for more details)

or calculated by

T = P/G:

T = Component temperature rise (°C)

 P = Power dissipation of the component (mW)

 G = Heat conductivity of the component (mW/°C)

MEASURING THE COMPONENT TEMPERATURE

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

The temperature rise is given by

T = T

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 pulse 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”

Thermocouple

2

dU

dt

--------





2

0

T



dt

U

Rdc

dU

dt

--------





rated







