Dry capacitor test sample

How do you test a capacitor?

Due to their relatively low capacitance (0.20uF to 100.00uF), testing of the capacitors can be done with many standard digital multi-meters (DMM's). Meters such as the Fluke 110, 170, and 180 series can provide the required data necessary to determine the presence of a failed capacitor.

How do you test a failed capacitor?

Meters such as the Fluke 110, 170, and 180 series can provide the required data necessary to determine the presence of a failed capacitor. Although other test methods are available, such as live testing, this technical note is centered on testing capacitors in their de-energized state.

Can a 12 kV capacitor withstand a voltage test?

The capacitor shall also withstand a 1 minute power frequency withstand test of a test voltage applied between the capacitor terminals and earth. For 12 kV rated capacitors, the test voltage is 75% of 28 kV. Refer to IEC 60871 or AS 2897 for other ratings. The requirements of the test are satisfied if no disruptive discharge occurs.

Can a DMM detect a capacitor?

In reality, most manufactures produce capacitors in the 0 to +2% of its nominal nameplate rating. It is desirable to detect, remove, and replace open capacitors, shorted capacitors, and partially failed capacitors. Each of these conditions can be detected with a DMM as follows:

What factors should be considered when evaluating a capacitor protection system?

In making this evaluation, consideration must be given to the sensitivity of capacitor bank protection (such as unbalance protection) and the potential for a capacitor under test to inadvertently discharge stored energy into a protection system. In most cases secondary isolation of the protection system will be required.

Should a capacitor be tested before replacement?

It is therefore recommended that externally fused capacitors be tested before replacement in situations where the external fuse has blown. For internally fused capacitors, testing is required as the fuse is not visible. The following test procedure requires the capacitor/harmonic filter bank to be grounded and disconnected.