0
\$\begingroup\$

As I understand electrolytic capacitors fail eventually after some years of use. Is there something else that breaks down too? Because changing inverter just because its capacitors are gone is really stupid and expensive.

\$\endgroup\$
1
  • \$\begingroup\$ Sometimes, yes there is. \$\endgroup\$ Jan 29 at 15:50
0
\$\begingroup\$

Electrolytic capacitors (e-caps) fail as per their MTBF (mean time between failures). By fail I mean they go open circuit or short circuit. Typical value is 2 million hours (a ball park figure).

However, after a few years of use, e-caps will degrade depending on their operational service values of voltage, temperature and ripple current. That doesn't mean they fail because, MTBF and long term degradation are unrelated. But they will degrade over the years to have maybe 30 to 50% less capacitance. Leakage current may also be higher after several years. ESR (effective series resistance) may also be higher after several years.

If the designer of the inverter didn't consider the slow degradation of e-caps and, the inverter prematurely fails to operate correctly, it makes sense to replace the e-caps if it is commercially feasible.

\$\endgroup\$
2
  • \$\begingroup\$ From what I have observed with the failure of the cheaper units is that simple items like a small diode fail and cause the inverter IGBTs to self destruct. Costs are cut in the wrong place. \$\endgroup\$
    – Kartman
    Jan 29 at 14:52
  • \$\begingroup\$ @Kartman diodes do fail a lot in inverters. Knock-on effects can easily happen. Weak design or misapplication. \$\endgroup\$
    – Andy aka
    Jan 29 at 14:55
0
\$\begingroup\$

Relays can also fail. If you hear clicking noises from the inverter when it starts up, then it's probably connecting its internal generation circuits to the supply through relays.

After several years of turning on and off, the contacts can fail, meaning that the whole inverter fails.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.