Like batteries, capacitors degrade over time.A typical capacitor may be rated by the manufacturer as being able to maintain 24 hours a day for about seven years.However, under favorable operating conditions, it can provide up to 10 years of normal service life.
Failure occurs when the capacitor fails, your data center operations management researchers could not see any visible effect, but other capacitor will have to bear the workload, it will shorten its service life.In many cases, a capacitor fault triggers the UPS switch to bypass mode, during which it cannot protect the downstream workload.
In order to maximize the performance and reliability of UPS, treat capacitors as perishable goods and plan to replace capacitors at the end of their rated service life or near the end of their life.Relevant service provider's customer service engineers can help the enterprise data center operations management diagnosis UPS in the condition of the condenser, and when necessary to provide full or partial replacement of capacitor group, in order to keep UPS performance to factory specifications.Active attention to this often overlooked UPS architecture element: the humble capacitor can be extended to protect the value of the UPS system used to protect critical electronic systems.
1. What is a capacitor?
A capacitor is a fairly simple electronic device that can store and release electricity.These devices can be as small as a thimble or as big as a soda can -- depending on the amount of voltage they are expected to digest (that is, their rated capacity).
Capacitors are usually wrapped in aluminum or chrome-plated cylinders containing a pair of conductive surfaces (usually metal plates or electrodes) that are separated and insulated by a third element called a dielectric.
Why is this important?In addition to the surface area of the aluminum sheet, the thickness of the dielectric layer determines the entire capacitance - that is, the capacitor can store or manage how much charge.The ultrathin oxide layer has significant insulating properties, which makes it possible to make very small capacitors to handle very high workloads.
2. What can the ac and dc containers do?
The main purpose of dc containers in UPS applications is to smooth voltage fluctuations - a process known as "power voltage filtering".If the input voltage changes, the capacitor will reduce the voltage change, eliminate the peak and fill the peak valley, thus helping to maintain a constant voltage level.
Ac capacitors have many of the same characteristics as dc containers because they have predictable limited service deadlines and should be considered perishable goods.Ac capacitors mainly exist in the input and output filters of UPS.They eliminated the input transient and reduce harmonic distortion at the input to UPS, what is more important: they are directly connected to the output of the critical workload, and help shape control of UPS output voltage waveform.
3. How many capacitors are in a typical UPS device?
The specific inventory of the capacitors inside the UPS varies greatly depending on the work done (i.e., the kVA rating of the device).From this perspective, a typical personal computer contains about 50 capacitors;A 750-kva UPS device could have hundreds of capacitors.Even the smallest UPS devices require dozens of capacitors.
4. Do manufacturers use proprietary capacitor design?
Capacitor products in the current market are manufactured by various suppliers according to the uniform standards of the industry.The likely scenario is that wherever your company purchases UPS devices, it contains capacitor products from the same major domestic or global supplier.
5. In normal use, will the capacitor be degraded over time?
Indeed, like battery, in the normal design and manufacturing, the wet in normal work under the rated voltage of capacitor, its basic characteristics will very slow changes over time.However, the paper, aluminum foil and electrolyte inside the capacitor are normal faults.As these materials age and begin to degrade physically and chemically, they lose their capacitance.Eventually, the capacitor will no longer be able to perform its work.Adverse operating conditions, such as excessive current and heat, may accelerate the loss of capacitors.
6. How long can the capacitor normally run?
The theoretical operating life of the capacitor is calculated according to the corresponding mathematical function of the rated voltage, the applied voltage, the current of the capacitor, the ambient temperature and the thermal resistance.In fact, your enterprise data center can estimate the expected service life based on the manufacturer's rated life and the working temperature of the device.The higher the working temperature, the shorter the life.
According to the manufacturer's rated service life, we suggested the enterprise data center operations management personnel should be in your UPS equipment running full seven years later, arrange for the corresponding UPS power system the capacitor used by implementing a complete replacement.However, newer UPS typically have an oil-filled dc capacitor, which is rated for the entire life of UPS.
When the capacitor failure occurs, you might not see any visible effect, but other capacitor will have to bear the workload, which in turn will shorten the service life of the other remaining capacitor.In many cases, failure of the capacitor triggers the UPS switch to bypass mode, during which the downstream workload cannot be protected.
Type of capacitor
Rated service life
DC direct current container (electrolysis)
Service life with UPS.
DC direct current container (oil filled)
7 years
AC capacitor (oil filled)
7 years
7. Which conditions affect the service life of the capacitor?
Due to the service life of the capacitor is made up of rated voltage and operating temperature is calculated based on the function, so by any area beyond its design threshold to shorten the service life of the capacitor is logical.Such as:
Excessive current - if the capacitor is constantly exposed to overload current conditions, such as stable current exceeding the manufacturer's rating, the capacitor may be damaged.As long as the capacitor does not have to overheat to compensate, the short period of excessive Ripple current is relatively harmless.
Low overwork - if the capacitor filter must be unusual or frequent transient voltage noise (sine wave in the sharp short interruption), the failure of the capacitor failure frequency will be higher.As with air filters working in dirty environments, the worse the environment, the sooner it will have to be replaced.
Low excess calories - whether from inside the capacitor (for example because of the air filter clogging, airflow and cause confusing or caused by operating environment temperature overheating), excess heat will eventually start of solution inside the evaporative condenser, and unsafe pressure formation, which may result in the failure to fail.
For example, at 405 V and 20c, a capacitor has a theoretical life span of 32 years.If your enterprise data center increases the workload to 540 volts and doubles the heat, the capacitor may only last about eight years.
The good news is that with good management, for example, running in a clean, cool data center operating environment with rated capacity can help the UPS device mitigate these risk factors.
What happens to the capacitor when something goes wrong?
The capacitor may fail in the "open" state - just stop the scheduled work.The failure of this failure is quiet and negligible.Or a capacitor might malfunction in the "short circuit" - a dielectric leak, or even sound like a firecracker.
Of course, the electrolyte is conductive, so the overflow of the electrolyte can cause unintentional connections, which could damage the performance of the UPS device.The electrolyte is also corrosive, which may interact with other parts of the device.For these reasons, a lot of one end of the electrolytic capacitor has a notch, it is designed to be easily broken and leak, rather than let the container suddenly deflated, and electrolyte spread over a very wide area.
9. What happens to the function of the UPS device when the capacitor fails?
This depends on the location of the capacitor, the number of capacitors in series (series) or parallel work, to perform the same task, and the overall operation of other capacitors., for example, if the capacitor is much lower than the rated voltage of the voltage under the condition of operation is good, is one of the paragraph or two capacitors may be easier to take over the failure of capacitor, without significantly affect the operation of UPS.
A capacitor in the power transmission system may reduce the overall filtering capability of the device, but it will not cause the equipment to work properly.
However, when a capacitor in the power transmission system fails, a typical three-phase UPS device will switch to the bypass mode, allowing the power to bypass the filter electronics of the UPS device.During this time, UPS, while running, did not actually protect downstream devices.
In rare cases, a malfunction of the capacitor may interrupt the power supply (logical processors), but the leading UPS is designed to ensure that in such a small number of cases, perform a safe and orderly shutdown.Whether or not a single component performs a critical task, it is not a good thing for the entire architecture to have a component short circuit within the device.
10. If UPS continues to work, why should the operation managers of the enterprise data center worry about replacing the capacitor?
When a single capacitor fails, this usually indicates that other capacitors have not completed their work.Your enterprise data center may see clear one or two signs of capacitor division or spill, but visible detection will not find other capacitor in "open" state failure, and may actually cause the other's fault.If not controlled, this could cause more capacitors to fail and eventually lead to a performance degradation of the UPS device.
Capacitor replacement is absolutely in the category of preventive maintenance.When the corresponding monitoring report shows a decline in performance, the process itself will continue, and the cost of replacement will be much higher than the cost of identifying and replacing the scrapped capacitors in the early stages.
11. What can enterprise data center operation managers do to help extend the service life of the capacitor?
Under the control of your data center operation managers, the most likely factor is to maintain recommended operating environment temperature, humidity and cleanliness.Keep the air filter clean to ensure that the air can flow freely to keep the device cool.When replacing the capacitor on the old equipment, do not install the capacitor below the rated voltage of the original part.
Good data center management can be a powerful booster for extending equipment life.We recommend the use of complete power capacitor substitutes to actively ensure the reliability of UPS equipment, avoid catastrophic failure, and reduce the risk of unplanned outage.
conclusion
In order to maximize the performance and reliability of the enterprise data center UPS equipment, please see capacitor as perishable goods, and plans at the end of its rated service life or close to the end of its life to the timely replacement.Carefully select the technical staff of a third-party service agency that has been certified by the UPS equipment manufacturer to help you change the capacitor in your data center.
If the manufacturing company is responsible for designing and manufacturing UPS devices purchased by your data center, then their technicians or experts will know more about these devices than others.These technical staff have received professional training, they can obtain the relevant certification, proprietary, and may access the diagnostic software and the latest project updates, and can obtain the UPS equipment manufacturer level technical support (including all documents, engineering data and drawings, technical data and updates).Your data center can rest assured that only the factory authorized parts with the appropriate specifications and latest firmware or revised version will be installed in your UPS device, not the unknown quality or specification accessories.
In short, the enterprise data center operations management is often ignored by researchers take the initiative to focus on the UPS architectural elements: simple capacitor, can enhance your enterprise to rely on its key electronic systems to protect your company the confidence of the UPS system.
沒有留言:
張貼留言