Your shopping cart is empty! Please select the type which you want.
Home > Mall Dynamic > Why Do Capacitors Fail?Several Ways To Detect Whether The Capacitor Is Faulty
With the rapid development of electronic information technology, the update speed of digital electronic products is getting faster and faster, and the utilization rate of capacitors in digital products and electronic products is getting higher and higher. Do you know what usually happens to your capacitors? When it fails, what are the emergency treatment methods? This article will explain some common causes of capacitor failure, and how to determine whether the capacitor is faulty
1.If the capacitor shell is deformed and the bulge is found, the insulating medium or electrode inside the capacitor must be damaged, and the operation should be scrapped immediately and replaced with new products.
2. If the capacitor high voltage porcelain bottle is found to flash and burst or there has been oil injection and overflow of the internal insulation medium, it should also be immediately judged as capacitor damage, and the damaged products should be properly handled and recovered and replaced with new products.
3, the capacitor in normal operation, should not have any sound. If you hear an abnormal "snap", "snap" discharge sound or "buzz" dull sound, indicating that the capacitor must be faulty inside, should be immediately shut down for further inspection or replacement of new products.
1, the capacitor itself product quality problems, such as manufacturing process, material unqualified, the marked capacity is not consistent with the actual capacity, the use of long time leading to aging will cause burnout.
2, the impact of the external environment, such as installed in a place where heat dissipation is not good or near the heat source, capacitor wiring is not good, poor contact, etc., is also easy to cause burn out.
3, harmonic problems, harmonics make the filter capacitor resonant, resulting in capacitor overcurrent, burned out.
4, the voltage is too low; Centrifugal switch adhesion.
5, overload; Low speed and repeated start; Or the startup time is long. It is necessary to analyze and judge the scene of the capacitor burning, and gradually investigate the cause of the failure, sometimes small details may also be the cause of its burning.
1, because the two poles of the capacitor have the characteristics of remaining residual charge, so we should first try to discharge its charge, otherwise it is prone to electric shock.
2. When dealing with faulty capacitors, the circuit breaker of the capacitor bank and its upper and lower isolation switch should be opened first. If the fuse protection is used, the fuse tube should be removed first.
3. At this time, although the capacitor bank has been self-discharging through the discharge resistance, there will still be some residual charge, so it must be manually discharged. When discharging, the grounding end of the grounding wire should be fixed with the grounding network first, and then the grounding rod should be used to discharge the capacitor several times until there is no spark and discharge sound, and finally the grounding wire should be fixed.
4, at the same time, it should also be noted that if the capacitor has an internal break, fuse fuse or poor lead contact, there may be a residual charge between the poles, and these residual charges will not be discharged when the automatic discharge or artificial discharge.
5, so the operation or maintenance personnel in contact with the faulty capacitor, should also wear insulation gloves, and use a short route to short-circuit the poles of the faulty capacitor to discharge. In addition, the capacitor using the series connection mode should also be discharged separately.
In summary, the capacitor itself is a start-up operation protection of electrical appliances, and many electrical appliances use different types of capacitors for start-up and operation. It is assumed that if there is no capacitor, unstable voltage and large current load will easily affect the service life of electrical appliances.
1. Influence of environment and temperature
◎ Temperature is too high
◎ Bad heat dissipation of capacitor disc
◎ Insufficient installation spacing of adjacent capacitors, poor heat dissipation
2. Improper operation
◎ Low voltage capacitor should be reduced to 1 minute after power failure
Below 50V
◎ High voltage capacitor should be reduced to 10 minutes after power failure
Up to 75V
◎ Residual voltage does not drop below the safe value,
That is, to re-invest
3. Improper selection of protective devices
◎ High voltage switch, Fuse or NFB
◎ Wire diameter selection
◎ Contactor (MC) level (at least AC3 level)
◎ Selection of UV, OV and timer
◎ Imbalance protection
4. Overcurrent
◎ Due to harmonic effects
◎ Resonance phenomenon causes harmonic value amplification
5. Inrush current
◎ According to IEC 60947-4-1 Table7b
Inrush current value:
◎ Up to 100 times Isc rating
6. Overvoltage
◎ Capacitor voltage should comply with IEC 60831-1
Or IEC 60871-1
◎ Improper selection of capacitor voltage resistance
7. Series resonance
◎ Harmonics of the power supply system interact with capacitors
◎ will cause overvoltage
8. Parallel resonance
◎ The influence of harmonic generation source equipment and capacitors
◎ will cause excessive current
9. Bad combinations
◎ No series reactor is configured
◎ Improper selection of reactor specifications, 6%, 8%
or 13%
◎ The current resistance of reactor is insufficient
◎ The impedance matching between the reactor and the capacitor is controversial
10. Equipment factor
◎ Capacitor failure and aging
◎ The reactor has insufficient current resistance, and the magnetic pass is saturated
◎ Poor production quality, C or XL/XC value floating
◎ resonance frequency (resonance frequency) abnormal or out of control
Mall Dynamic
