PPR Range

The PPR range of capacitors utilise a mixed dielectric material that consists of polyester or polypropylene film and capacitor paper and are impregnated and filled with a mineral oil. The container is a robust rectangular polypropylene case. The internal construction is designed to prevent movement when the capacitor is subjected to mechanical shock or vibration. An inert welding process ensures hermetic sealing. Standard terminations are M10 threaded inserts as the plastic case eliminates the need for large high voltage stand-off terminals. (Other terminal types are available on request). The case has an extremely low affinity for moisture and is resistant to virtually all electrical environments. Brackets can be welded on as required.

NOTE: The impregnant used is a non toxic highly refined, purified and inhibited mineral oil.

APPLICATIONS:The PPR range is designed specifically for DC applications such as filters, bypass, coupling, rapid discharge, pulse forming networks and high voltage power supplies such as those found in radar, laser and X-ray equipment. They are particularly suited for use in portable equipment.

Capacitance Range: 0.002µF – 100µF. The tolerance is +/-10%. Other tolerances are available on request. Nominal values measured at 1kHz.

Temperature Range: -40°C to 85°C. The nominal voltage rating is applicable from -55°C to 85°C. Derating is required for higher operating temperatures.

Temperature Coefficient: Capacitance will increase by 2% per 100°C temperature change.

Voltage Range: 1kVDC – 300kVDC

RIPPLE:

Ripple: The sum of the peak ripple voltage and the DC voltage should not exceed the rated voltage. The graph above shows permissible peak-to-peak ripple voltage as a percentage of rated voltage for various frequencies.

Power Factor

Power Factor: Variable; function of temperature and frequency. See fig 2. Nominal value < 0.5% at 20ºC.

Dieletric Resistance

Dieletric Resistance: (Parallel resistance) Indicated by the graph of insulance (Mohms x µF) vs Temperature (fig 3). The insulance(Mohms x µF) is nominally 10000s at +20ºC. (Measurements taken after 1 minute with an applied voltage of 500V).

Life expectancy

Life expectancy: PPR type capacitors are designed for a life expectancy of 50000 hours at 65ºC. To achieve the same life expectancy at 85ºC derate to 60% of rated voltage.