LOWER CATEGORY TEMPERATURE
The minimum ambient temperature for which a capacitor has been designed to operate continuously. |
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UPPER CATEGORY TEMPERATURE
The maximum ambient temperature for which a capacitor has been designed to operate continuously. |
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SELF HEALING
The process by which the electrical properties of the capacitor, after a local breakdown of the dielectric, are rapidly restored to those before the breakdown. |
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| RATED VOLTAGE |
| The maximum direct voltage or the maximum r.m.s. alternating voltage or peak value of pulse voltage which may be applied continuously to a capacitor at any temperature between the lower category temperature and the rated temperature. |
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| RATED CAPACITANCE |
The capacitance value for which the capacitor has been designed and which is usually indicated upon it.
The capacitance shall be measured at one of the following frequencies unless otherwise prescribed by the relevant specification:
CR< 1 nf : 10 kHz
1 nf < CR £ 10 mf : 1 kHz
CR> 10 mf : 50 Hz
The tolerance on all frequencies for measuring purposes shall not exceed ±20%.
The measuring voltage shall not exceed 3% of rated voltage or 5 VRMS (whichever is lower) unless otherwise prescribed in the relevant specification. |
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| INSULATION RESISTANCE |
| The insulation resistance is the quotient of an applied DC voltage to the current flowing after a specified time. |
| R(insulation) = |
V(applied voltage) |
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I (leakage current) |
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The time constant (S) = M W ´ Mf
= Insulation Resistance ´ Rated Capacitance
Before this measurement is made, the capacitors shall be fully discharged. The insulation resistance shall be measured, at the following measuring voltage, between the points specified.
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| Voltage rating of capacitor |
Measuring voltage |
| UR < 10 V |
UR ± 10% |
| 10 V £ UR < 100 V |
10 ± 1 V |
| 100 V £ UR < 500 V |
100 ± 15 V |
| 500 V £ UR |
500 ± 50 V |
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| The insulation resistance shall be measured after the voltage has been applied for 1 min ± 5 sec. |
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