PMR Range

The PMR range are impregnated and filled with a mineral oil. The container is a rolled-seamed tin plate case that is hermetically sealed. The internal construction is designed to prevent movement when the capacitor is subjected to mechanical shock or vibration. External connections are via ceramic terminals with threaded studs or solder tags. Capacitor are supplied with clip-on brackets. Other brackets are available on request. These capacitors can be mounted in any postion. The finish is a coat of high build light grey weatherwork cellulose enamel paint (other colours available on request).

Note the impregnant used is a non toxic highly refined, purified and inhibited mineral oil.

APPLICATIONS

The PMR Range of capacitors is specifically designed for DC apllications such as filters, bypass and coupling of low frequency audio. Other apllications include:

• Pulse forming networks
• Oscillator Circuits
• Energy Storage
• Arc and Spark Suppression
• Integrating Circuits
• High Voltage Smoothing

Other Information

Capacitors required for A.C. applications and High Discharge rates can also be designed from the PMR range. Consult Hivolt Capacitors Limited for your specific requirements.

Capacitance Range: 0.01µF – 100µF. The tolerance is +/-10%. Other tolerances are available on request. Nominal values measured at 1kHz.

Temperature Range: -55°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: 200Vdc – 40kVdc

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.

TEST VOLTAGE: V TEST

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: PMR 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.

Weight: The approximate weight in kg of capacitors in the PMR range can be estimated by multiplying the volume of the capacitor container (in cubic mm) by 1.45 x 10-6

Flashover

V Rated < 5kV, the terminals will withstand 125% of rated voltage without flashover @ 85mm Hg (equivalent to 50000 ft altitude).

V Rated > 5kV, the terminals will withstand 125% of rated voltage without flashover @ 500mm Hg (equivalent to 10000 ft altitude).