There is a norm that since capacitor banks are static type electrical equipment, regular maintenance is not required. But capacitors need to be monitored and maintained regularly. The unawareness and the negligence of the users may leads to reduce the life expectancy or failures of the capacitors which would cause an ultimate loss for your investment.


During the design, assembling, installation, inspection and maintenance criterions relevant manufacturer standards and safety practices should be adhered. In this context the important practices of inspection and maintenance of Capacitor Bank is discussed.


Visual Inspection


This is the first and basic step of a maintenance procedure which is govern to find the condition and the status of the equipment for blown capacitor fuses, flashovers over the insulating materials, capacitor unit leaks, bulged cases, discolored cases, over pressure disconnections has operated and ruptured cases.

An infrared thermal camera will be useful for inspecting the hotspots for overheated joints, capacitors and surfaces while the capacitor bank is energized. These records can be maintained for future references.


Discharge the capacitors before do any maintenance work


As we all know, a capacitor is an electrical energy storage device. Hence even after de-energizing a capacitor, residual charges will be there. After a capacitor bank is de-energized at least 5-10 minutes should be waited before approaching it. With that it allows sufficient time for the capacitors to internally discharge through the resistors in each capacitor unit and the stored electrical energy will be dissipated through the resistor as heat. These discharging resistors are designed, when the supply voltage is switched off it will keep a 75V maximum voltage within 60 seconds.


Therefore, wait before approaching it to allow sufficient time for the internal discharge resistors in each capacitor unit to dissipate the stored energy.

How to check whether the discharging resistor is working?


Bulged capacitors and leaking capacitors should be removed


Under excessive high-voltage or high-current stressing, the capacitor may overheat or excessively arc. This generates gases that can cause the capacitor to bulge. As a capacitor eventually fails, it may eject molten dielectric film, or even small flames, through the sides or ends of the capacitor.


Due to the failures of the cans capacitors can cause leaking. When handling these capacitors avoid contact with the skin and take measures to prevent entry into sensitive areas such as eyes. Some of these liquids are combustible liquids and these should be handled with care.

Handling and disposal of capacitor insulating fluid should comply with local regulations and other health and safety measures.


Re-energizing buying nolvadex online in usa the best foods to the capacitors


Allow a minimum of 5 minutes between de-energization of the capacitor bank and re-energization of the capacitor bank to allow enough time for the stored energy to dissipate.


Inspection criterions carried out before energizing the capacitor bank


Check whether the mechanical assembly of the capacitor units is in line with the electrical code providing enough clearance and ventilation.


Ex: Voltage Input: L1 & L2

Current input from CT: L3


For 3-phase delta connected capacitor



Ex: As a norm if the non-linear loads > 50% total load, detuned reactors are considered


Useful life of the capacitors


Even the manufacturer has recommended certain useful life of the capacitors, that depends on several factors as follows

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