UL-810B:2016 pdf free download – STANDARD FOR SAFETY Standard for DC Power Capacitors.
14 Dielectric Voltage-Withstand Test
14.1 Test between terminals and enclosure
14.1.1 Capacitors having all terminals insulated from the enclosure shall be subjected to a dielectric voltage-withstand test as described in 14.1.2. There shall be no dielectric breakdown of any sample tested.
14.1.2 To determine if a capacitor complies with the requirements in 14.1.1, the capacitor is to be tested using a 500 VA or larger capacity transformer, the output voltage of which can be varied. The applied potential is to be increased from zero until the required test level is reached, and is to be held at that level for 1 mm. The increase in applied potential is to be at a substantially uniform rate as rapid as is consistent with correct indication of its value by a voltmeter.
14.1.3 As an alternative, a dc potential equal to 1.4 times the ac potential specified in 14.1.4 may be used.
14.1.4 The test voltage applied shall consist of a 50 or 60 Hz alternating potential of thousand volts plus twice the rated voltage applied between terminals and enclosure.
14.1.5 A capacitor with a nonmetallic enclosure is to be tested by applying the voltage between the terminals and a metal foil tightly wrapped around and contacting all surfaces other than the surface on which the terminals are attached.
14.2 Test between terminals
14.2.1 Capacitors shall be subjected to a dielectric voltage-withstand test as described in 14.2.2. There shall be no dielectric breakdown of any sample tested.
14.2.2 To determine if a capacitor complies with the requirements in 14.2.1, the capacitor is to be tested using a dc potential as noted in 14.2.4
14.2.3 The applied potential is to be increased from zero until the required test level is reached, and is to be held at that level for 1 mm. The increase in applied potential is to be at a substantially uniform rate as rapid as is consistent with correct indication of its value by a voltmeter.
14.2.4 The test voltage applied shall consist of a dc potential of:
a) One and a half times the maximum rated voltage applied between terminals for capacitors with metallized film electrodes; or
b) Two times the maximum rated voltage applied between terminals for capacitors with other than metallized film electrodes.
15 Heating (Sealing) Test
15.1 Capacitors other than dry type capacitors shall be subjected to the heating test as noted below. During the test, temperatures on the capacitor case shall be monitored by means of a thermocouple.
15.2 The capacitor shall be mounted in a position most likely to reveal leakage within a test chamber at a temperature 10°C ±2°C (50 ±3.6°F) higher than the maximum permissible capacitor operating temperature. The capacitor shall be subjected to the elevated temperature until it reaches thermal stabilization at the test temperature. After thermal stabilization, the capacitor shall be maintained at the test temperature for an additional hour. At the conclusion of the conditioning, the capacitor shall be removed from the test chamber and allowed to cool to room temperature.
15.3 After cooling to room temperature, the capacitor shall be visually examined for leakage and other signs of damage. As a result of the conditioning, there shall be no visible signs of liquid leakage or other damage.
16 Humidity Test
16.1 Prior to the humidity conditioning, the capacitor is to be stored at 20 ±5°C (68 ±9°F) for 24 h at 45% — 75% relative humidity (RH). The capacitor is then to be subjected to humidity conditioning for 48 h in a chamber at 32 ±2°C (89.6 ±3.6°F) at a relative humidity (RH) of 88 ±2%.