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Typical methods of installing a large aluminum electrolytic capacitor

Writer:sunny yangSource:capsun Date:2012-12-12 10:42

Typical methods of installing a large aluminum electrolytic capacitor
(1) Insulation holder
    Best suited for improving insulation and vibration resistance and for cutting back on assembly costs. (For details, see the Technical Report.)

(2) Stud screw capacitor
    Best suited for cutting back on assembly costs. (For vibration and dielectric  resistance, consult company capsun for the details.)

(3) Other
  Useful not only as capacitors but also as a part of a capacitor unit



Service Life of an Aluminum Electrolytic Capacitor
[Factors affecting service life]
Environmental factors affecting the service life of an aluminum electrolytic capacitor include temperature,
humidity and vibration (environment), as well as electrical factors, applied voltage, ripple current and
charging/discharging conditions. In capacitors for mid-to-high-voltage filters, temperature and applied
voltage are the most important controlling factors. The estimated service life may be calculated based on
the core temperature of the capacitor and the applied voltage
[Temperature conditions]
Capacitance change or tangent change for loss angle indicates that the product life has been affected by
temperature. Generally, as the ambient temperature (neighboring temperature of the capacitor) increases,
capacitance decreases and tangent change for loss angle takes place more rapidly. This is mainly because
electrolytic solution generates gas due to electrode reaction and diffuses it outside via a sealing rubber. The
following expression (1) indicates the relation between the ambient temperature and electric characteristic
that changes with time (while the capacitor is used normally according to the rules of serviceability)

Where,
L : Estimated service life in actual use
L0 : Standard service life when allowable ripple current load or rated voltage is
applied at the maximum operating temperature
T0 : Maximum core temperature setting when subjected to the maximum allowable
ripple load at the maximum operating temperature (settings differ in different
series or products. Contact us for details)
T : Core temperature of the capacitor during actual use
Therefore, the lower the core temperature of the capacitor during actual use, the longer the estimated
service life is. The core temperature of a capacitor may be lowered by lowering either the ambient
temperature or the load current (operating conditions), or by either boosting capacitance or lowering
internal resistance. Some capacitors feature a radiating structure to lower the core temperature. Consult
us for the selection of capacitors

[Voltage conditions]

The service life of an aluminum electrolytic capacitor for mid- to high-voltage filters is affected by the
applied voltage. If the applied voltage is between 60% and 100% of the rated voltage, the estimated
service can be extended by lowering the applied voltage below the rated voltage. However, if the applied
voltage is less than 60% of the rated voltage or the capacitor is used in low-pressure (100 WV or less)
applications, the impact of the applied voltage on the service life is negligible. Therefore, service life is
estimated assuming no impact from voltage
Continuous application of a voltage over the rated voltage rapidly increases leakage current in a
capacitor. This may increase internal pressure due to generation of gases, resulting in activation of the
safety vent in a short time and/or formation of an internal short circuit. For this reason, the applied voltage
must be maintained below the rated voltage during use. Besides, it should be noted that the circuit design
is such that the applied voltage will remain 80% or less of the rated voltage during use.
Where more than one capacitor connected in series is used, the applied voltages across the individual
capacitors may become out of balance, resulting in the application of excessive voltage to them. To avoid
this, either choose a rated voltage allowing for voltage imbalances, or connect a voltage divider
(resistors) to the capacitors
[Formula for estimating service life]
1. Estimating from the capacitor's core temperature and applied voltage
Formula for calculating the service life of our capacitors in mid-to-high voltage applications (filters)



Where,
T0 : Maximum core temperature setting when subjected to the maximum allowable
ripple load at the maximum operating temperature
L0 : Standard service life when core temperature is T0 and rated voltage is (WV)
L : Estimated service life when core temperature is T and applied voltage is (V)
If V/WV<0.6, use V/WV = 0.6.
2. Estimating core temperature of a capacitor from load ripple current
We recommend that you estimate service life by measuring the capacitor's core temperature with a
thermocouple. We can manufacture samples with inserted thermocouples according to customer requests.
If for some reason it is impossible to measure the core temperature, you can estimate the service life by
making a rough estimate of the capacitor's core temperature from the load ripple current. As shown below,
assuming the rise in temperature and the square of load current to be nearly proportionate, obtain the
capacitor's core temperature that occurs when the capacitor is loaded with a ripple current



Where,
T : Capacitor's core temperature when ripple current I is loaded
Ta : Ambient temperature
T0 : Rise in maximum core temperature setting for the capacitor when allowable ripple current
IR is loaded
(settings differ in different series or products. Contact us for details)
Note: observe the :I≤IR. Never use a capacitor loaded with a ripple current greater than IR For safety reasons,

estimate the service life on the basis of the capacitor's core temperature at maximum
load. Temperature distribution should be taken into account when more than one capacitor is used.
[Other factors affecting service life]
(1) Reverse voltage
When a reverse voltage is applied to the capacitor, the capacitor's cathode foil that is not coated with
oxide is energized, resulting in forced formation of an oxide film on its surface. During the process of
forced formation, heat and gases are generated. This will shorten the service life significantly.
(2) Charge and discharge
Generally, where aluminum electrolytic capacitors are used in a charge/discharge circuit, oxide films
are gradually formed on the surfaces of their cathode foils due to discharge current. This will shorten
the service life significantly. For this reason, general-purpose capacitors are not suitable for circuits
in which frequent charge and discharge are common. Examples include circuits for photo flash and
welding.
(3) Inrush current
Upon switching on the power supply of a welding machine, a large current flows instantaneously at the
beginning of charging. Such a current, called an inrush current, is 10 to 1,000 times as large as the
normal value. Inrush currents pose no problem as long as they occur with very low freguent during
operation. The reason for this is that their heat-generating energy is relatively small. However, if an
inrush current occurs repeatedly during operation, it may shorten the service life significantly
As part of our initiatives for global environment protection under ISO 14001, we recommend products
without any substances with environmental impact to our customers
(1) Lead-free
Regarding Snap-in type Aluminum Electrolytic Capacitors, our standard specification is to use tin
instead of Lead on the surface of terminal plating. If the products are Tin + Lead plating specification,
we request to change to the Lead-Free products. In case of Lead-Free products, it is necessary to raise
the temperature of soldering by 5-20°C. Regarding Screw terminal type Aluminum Electrolytic
Capacitors, they do not contain Lead at all.
Please contact us for details
Scope: all snap mount aluminum electrolytic capacitors
* Note that lead-free treatment may not be applied on the spot depending on the terminal shape of
capacitors not found in the catalog.
(2) PET-free
We use PVC for exterior materials (sleeve, plate).
According to customers' request, we are ready to use the substitutions such as, PET for Snap-in type
(Dia. less than 41mm), Polyolefin for Snap-in type (DIa. more than 46mm) and Screw terminal type.
In case of Snap-in type with PVC-Free, we attach the sleeve but no bottom plate as the exterior
materials.
(3) Eliminating Chromate Treatment
The previous chromate treatment on the surface of bracket contained hexavalent chromium.
To avoid this material, we changed to trivalent chromium.
The surface treatment is changed but no change in size or other specification
LB Type  [Large industrial power, large machinery, central air conditioning, power distribution cabinet
LWS Type [Large industrial power, large machinery, central air conditioning, power distribution cabinet]
LD Type [Suitable for soldering machine, laser cutting ,Energy storage machine  with life or over 500000Time

                or 2 years of guarantee period]
LLD Type [Suitable for soldering machine, laser cutting ,Energy storage machine with life or over 1 millions

                or 3 years of guarantee period]
LHD Type [Suitable for soldering machine, with life or over 3 millions or 5 years of guarantee period using

                   foreign capacitor design philosophy, Panasonic branched ammonia salt and the surface of the nanometer

                    material to the electrolyte complexing agent, parameters and similar foreign capacitor equivalent]
LXD Type [Suitable for soldering machine,with life or over 5 millions or 8 years of guarantee period Integrated

                   foreign capacitor design philosophy, Panasonic branched ammonia salt and the surface of the nanometer

                   material of complexing agent on the electrolyte, the overall parameters of more than similar foreign capacitor]
LNB Type [High ripple capability]
LGR Type [High ripple capability than LHA series]
LCS Type [Downsized,high ripple version of LNB series 20%better ripple current at 300HZ than LNB series]
LNC Type [High ripple capability For train systems and high power consuming inverter circuits]
LG Type [Downsized,high ripple version]
LHA Type [Rated voltage range up to 525VDC FOR500vdc-525vdc) High ripple capability
LHR Type [For frequently change of regenerative voltage from AC servo amplifier and inverter control improved the

                   resistance for charge and discharge from same dimension of LNB series]
LHC Type [screw type  capacity products Suitable for high-end car audio]
LND Type [Super Low temperature aluminum electrolytic capacitor outdoor high-voltage switchgear, control gear ,

                  feeder terminal unit and transformer terminal unit for the power distribution systems. vacuum switches,

                outdoor high-voltage vacuum magnetic actuators automatic recloser,outdoor high-voltage

                  vacuum magnetic actuator's circuit-breakers]
LHH Type [Super High temperature aluminum electrolytic capacitor Suitable for large current under the high temperature

                     environment, For example  oil well  underground mine  5000 meters use environment]
LNP Type [bi-polar type for the circuit,of which polarity is frequently reversed]
Outline of drawings and dimensions (Unit : mm)



( )dimensions : Type LB, ø101 units
*Hexagon head bolt (standard)
Case code (A to F): M5•10
Case code (G): M6•12 (P=32.0)
(G case of LB series: M8•16 (P=41.5))
M6 bolt type can be design if reguested
*Hexagon head bolt (standard)
Case code (A to F): M5•10
Case code (G): M6•12 (P=32.0)
(G case of LB series: M8•16 (P=41.5)


M6 bolt type can be design if reguested


 

ØD

a

b

50-90

7

4.5

100

8

4.5

ØD

a

b

θ

50-76

6

4.5

45

90

7

5

30

*Size of w1~w4 might be changed
according to the material of outer sleave.
*When designing the size of mouting hole,
make sure the size by actual capacitors

TypeInfo: Industry information

Keywords for the information:reactive power for  a sinusoidal waveform voltage  an ideal capacitor 

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