[Explanation of the Cause of Capacitor Failure] The aluminum electrolytic capacitor sparked.
As a precaution, please discharge the accumulated charge before handling the capacitor!
During the replacement work of an aluminum electrolytic capacitor, when the terminals of the capacitor were connected with metal, a spark occurred, surprising the operator. When the capacitor is discharged, the charge stored in the electrodes disappears instantly, and the voltage between the terminals appears to be zero, but the dipole polarization of the dielectric is maintained. If the capacitor is opened with a short discharge time, the voltage is induced again at the electrodes due to the dipole polarization remaining in the dielectric. In other words, the charge stored in the dielectric seeps out and generates a re-induced voltage at the terminals. A spark occurred because the terminals were short-circuited with a conductor in this state. [Countermeasures] ■ Before handling the capacitor, connect a resistor of about 100Ω to 1kΩ between the terminals of the capacitor to discharge the accumulated charge. *For more details, please refer to the PDF document or feel free to contact us.
basic information
Please be aware of the following: ■ Typically, the occurrence of re-energization voltage peaks within 1 to 3 weeks, after which the voltage gradually decreases. ■ This is due to the relaxation of the polarized state of the dielectric. *For more details, please refer to the PDF document or feel free to contact us.*
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A Must-Read Guide for Circuit Designers: 15 Examples of Causes and Countermeasures for Capacitor Failures
Applications/Examples of results
If you observe the following symptoms in a capacitor, it is faulty: ■ The case is swollen (bulging) ■ There are cracks in the case ■ There is a gap between the case and the sealing part ■ The pressure valve has activated (the pressure valve has opened) ■ The case has burst ■ It is hot and generating heat ■ Smoke is coming out ■ There is liquid leakage ■ There are unusual sounds ■ There is an unusual smell *For more details, please refer to the PDF document or feel free to contact us.
