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Can capacitors go bad without bulging?
davenn Moderator. Now I’m assuming you are mainly refering to electrolytic capacitors, yes, they can be bad without any outwardly visible signs. Electro caps will quite happily dry out without bulging. Its generally the ones that are in hi temperature situations that bulge and blow their top.
Why does a capacitor bulge?
A capacitor’s dielectric has a maximum voltage called the breakdown voltage. An electrolytic capacitor’s chemicals boil and expand when exposed to excessive voltage. This causes the whole capacitor to bulge.
How can you tell if a capacitor is swollen?
Visible symptoms
- Bulging of the vent on top of the capacitor.
- Broken or cracked vent, often accompanied with visible crusty rust-like brown or red dried electrolyte deposits.
What causes the sides of a capacitor to bulge?
At the bottom, a plastic plug seals the chemicals and the capacitor’s electrical leads. If the component develops a problem, hydrogen gas accumulates in the can, eventually causing the sides to bulge.
How can you tell if a capacitor is bad?
Well, bad caps typically have a domed, or swollen top. Sometimes really bad caps can leak their electrolyte out of themselves too. Then you may see this brown crust around the capacitor, or perhaps on it. It often looks somewhat like a dried coffee stain.
When to contact an HVAC professional for a bad capacitor?
While it’s good to learn how to do basic repairs around the home, keep in mind that for more complex issues, it is infinitely safer (for you and for your air conditioner) to contact an HVAC professional. Now that that’s out of the way, let’s determine whether your AC issue is due to a bad capacitor.
Why do electrolytic capacitors break when pressure builds?
Modern electrolytic capacitors have X-shaped score lines cut into the top of the metal case. If pressure builds in the capacitor, the component will break safely and gradually at this weak spot, relieving the pressure, though not saving the component.