In addition, direct contact between the extended cathode aluminum foil and the capacitor aluminum shell is also a good way to reduce thermal resistance. At the same time, it should be noted that the aluminum shell will carry negative electricity and cannot be used as a negative electrode connection.
The capacitor must be installed correctly to achieve its designed working life. For example, the RIFAPEH169 series and PEH200 series should be installed vertically or horizontally. At the same time, ensure that the safety valve is facing upwards, so that hot electrolyte and vapor can be smoothly discharged from the safety valve in the event of capacitor failure.
When the capacitor arrangement is very compact, at least a 5mm gap should be left between adjacent capacitors to ensure appropriate air flow. When installing with bolts, the control of nut torque is very important. If tightened too loosely, there will be no close contact between the capacitor and the heat sink; If tightened too tightly, it may cause thread damage. At the same time, it should be noted that the capacitor should not be installed upside down, otherwise it may cause the bolt to break.
Capacitors should be installed as far away from heating elements as possible, otherwise excessively high temperatures will shorten the service life of the capacitor, making it the shortest lifespan component in the entire circuit. In high ambient temperatures, try to use forced air cooling and install the capacitor at the air inlet.
3. The impact of frequency
If the current is composed of fundamental frequency and multiple harmonics, the power loss value generated by each harmonic must be calculated, and the calculation results must be added to obtain the total loss value.
In high-frequency applications, the leads at both ends of the capacitor should be as short as possible to reduce the equivalent inductance.
The resonant frequency (fR) of capacitors varies depending on the type of capacitor. For the lug type and bolted type aluminum Electrolytic capacitor, the resonance frequency is between 1.5kHz and 150kHz. If a capacitor is used above the resonant frequency, its external characteristics are inductive.
To sum up, the life of Electrolytic capacitor can be guaranteed by selecting the correct application conditions and environment under the condition of avoiding abnormal failure.