Application Notes

■ Aluminum Electrolytic Capacitors
When you use aluminum electrolytic capacitors,remember the following.

◆ Polarity
  • Regular electrolytic Capacitor has polarity.
  • Reverse voltage causes short circuit breakage of the capacitor or leakage of electrolyte. Where the polarity in a circuit sometimes reversed or unknown, a bi-polar capacitor should be used.

◆ Overvoltage
  • Do not apply overvoltage continuously.
  • When overvoltage is applied to the capacitor, leakage current increase drastically. 。Applied working voltage to capacitors should not exceed the rated working voltage of capacitor.

◆ Operating temperature and life
  • Do not use the capacitor over the max operating temperature.
  • Life time of the capacitor depends on the temperature.
  • Generally, life time is doubled by decreasing each temperature 10℃.
  • Use temperature as low as possible.

◆ Vent
  • It is recommended at least 3mm of space around the vent.
  • If such space is not provided, the vent will not operate completely.

◆ Ripple current
  • Do not apply a ripple current exceeding the rated maximum ripple current.
  • Applying too much ripple current to the capacitor causes great heat generation, invites deterioration of properties of cases breakage.
  • Please consult factory if ripple current exceeds the specified limit.

◆ Charge and discharging
  • Frequent and quick charge/discharge generates heat inside the capacitor, causing increase of leakage current, decrease of capacitance, or breakage occasionally.
  • Consult us for assistance in this application.

◆ Storage
  • When the capacitor is stored for a long time without applying voltage, leakage current tends to increase.
  • This returns to normal by applying the rated voltage to the capacitor before use.
  • It is recommended to apply D.C. working voltage to the capacitor for 30 minutes through 1KΩ of protective series resistor, if it is stored for more than 6 months.
  • The capacitors should be stored at a normal temperature and humidity.

◆ Soldering
  • Improper soldering may shrink or break the insulating sleeve and/or damage the internal element as terminals and lead wires conduct heat into the capacitor.
  • Avoid too high a soldering temperature and/or too long a soldering time.

◆ Mechanical stress on the lead wire and the terminal
  • Do not apply excessive force to the lead wire and the terminal.
  • Do not move the capacitor after soldering to the PC board, not carry the PC hoard by picking up the capacitor. For their strength, refer to JIS C-5101-1:2010 and C-5101-4:2010.

◆ Cleaning of boards after soldering
  • If the capacitor is cleaned in halogenated solvent for organic removing solder flux solvent, the solvent may penetrate into the inside of capacitor, and may generate corrosion.

◆ Sleeve material
  • The standard sleeve matenal is polyethylene terephthalate.
  • If exposed to xylene, toluene, etc, and then subjected to high heat, the sleeve may crack. This sleeve is not insulating material.

◆ Standard
  • CapXon's Products meet quality standards specified by JIS-C-5101-1 and the reliability requirements refer to JIS-C-5101-4(non-SMD liquid capacitor), -18(Liquid SMD capacitor), -25(solid SMD capacitor), -26(solid Radial capacitor).

◆ No use of ozone deleting chemicals(ODC)
  • None of ozone depleting chemicals (ODC) under the Montreal Protocol is used in manufacturing process of CapXon.

◆ Reflow Condition for liquid SMD Type
  • Soldering Heat Resistance as below Temperature profile.
  • Solderability 245±5℃, 2±0.5 secs, 95% coverage min.
    Size Voltage Preheat Time maintained above 230℃ Peak temp Reflow
    number
    Temp. (T1 ~ T2) Time (t1) Temp. (T3) Time (t2) Temp. (T4) Time (t3)
    Φ3 ~ Φ6.3 4 to 50V 150℃ to 180℃ 120sec. max above 230℃ 30 sec. max 260℃ max. 10 sec. 2 times or less
    63 to 100V above 230℃ 30 sec. max 255℃ max 5 sec. 2 times or less
    Φ8 ~ Φ10 4 to 50V above 230℃ 30 sec. max 250℃ max. 5 sec. 2 times or less
    63 to 450V above 230℃ 30 sec. max 240℃ max. 5 sec. 2 times or less
    Φ12.5 ~ Φ16 4 to 50V above 230℃ 20 sec. max. 245℃ max 5 sec. 2 times or less
    63 to 450V above 230℃ - 235℃ max 5 sec. 2 times or less


    Note:
    1. Pre-heating shall be done at +150℃ to 180℃ and for 120 seconds.
    2. The duration of over T1 temperature at capacitor surface shall not exceed t1 seconds.
    3. The standard temperature profile is different by each reflow method.
    4. The reflow can acceptable twice. When finished the first time and the samples' temperature cool off and become stable then will proceed the 2nd time.
    5. If capacitors are subject to the conditions beyond the allowable range of reflow please contact us.



■ Conductive Polymer Capacitors
CP-CAP is a solid aluminum capacitor with conductive polymer electrolyte. Please read the following points in order to take the most out of your CP-CAP.

◆ Circuit devices designing
  1. Circuits where CP-CAP are prohibited to used:
    The leakage current of conductive polymer aluminum capacitors may vary depending on thermal stresses, the CP-CAP should avoid been using in the following types of circuits:
    (1) Coupling circuits
    (2) High-impedance circuits of sustaining voltages
    (3) Time constant circuits
    (4) Other circuits that are markedly affected by leakage current.
    If you want to use two or more CP-CAP in series or parallel connection, please contact us before use.

  2. Polarity
    The CP-CAP is a polarized solid aluminum electrolytic capacitor, don’t apply reverse voltages or AC voltages to the polarized capacitors. Using reverse polarity may cause a short problem. Reference the catalog, specifications or marking to verifying the polarity prior to use.

  3. Applied voltage
    Do not apply DC voltages exceeding the rated voltage. The peak voltage of accumulated AC voltages (ripple voltages) on DC voltages must not exceed the rated voltage.

  4. Ripple current
    Do not apply currents exceeding the rated ripple current. The overlapped large ripple current increases the thermal stress within the capacitor. This may cause the life reducing or damage of the capacitor.

  5. Operating temperature
    Using the temperature in the range of category stated, overranging may cause product deterioration or decrease the life of the capacitor.

  6. Sudden charge and discharge the capacitor
    Do not use the CP-CAP in continuously charged and discharged rapidly circuits. Repetitively large in-rush current may cause damage due to heat generating. It is recommend to use a protective circuit to insure reliability when rush currents exceed 10A.

  7. Failures and life-span
    The CP-CAP failure rate in use is based on level in the specification requirements. Upper category temperature and category voltage adhere to JIS C 5003 Standard. The confidence level is 60% and the failure rate is 0.5%/1,000 hours (applied rated voltage at category temperature).
    (1)Failure modes
    1. (1.1)The mainly failure mode is exhausted wear-out. In other words, capacitance decreases and ESR increases which lead capacitors become open mode, eventually. Besides, shorted circuit mode may happen during suffering over-voltage or excessive current applied onto the capacitors.
    2. (1.2)The contingency failure mode due to the thermal, electric or mechanical stress effected by soldering or environment conditions which lead to short problem.
      1. (i) Applied over rated voltage
      2. (ii)Applied reverse voltage
      3. (iii)Excessive mechanical stress
      4. (iv)Applied large excessive current
    3. (1.3)In case of shorted circuited, above (1.2) mentioned or other conditions will have a large amount of current flow through, the rubber gum bulged and might be with odor gas released.
    4. (1.4)CP-CAP contains flammable materials. If any large current flows through the capacitor after shorted circuited, the shorted part may spark, and in a worst case, may ignite. Ensure safety by fully considering when installing and in connect with a protective circuit.

  8. Circuit design
    Clarify the following before designing the circuit:
    (1) The electrical characters of the capacitor will vary depending on differences in temperature and frequency. It would better confirm the scope of these factors before designing.
    (2) When conjunction with two or more capacitors in parallel, ensure to balance the current flow in circuit.
    (3) When connecting two or more capacitors in series, variation of applied voltage may cause over-voltage conditions. Contact CapXon before using capacitors connected in series.

  9. Environment of capacitor usage
    Do not use/expose capacitors in the following conditions.
    (1) Oil, water, salty water, take care to avoid storage in damp locations.
    (2) Direct sunlight
    (3) Toxic gases such as hydrogen, sulfide, sulfurous acids, nitrous acids, chlorine and chlorine compounds, bromine and bromine compounds, ammonia, etc.
    (4) Ozone, ultraviolet rays and radiation.
    (5) Severe vibration or mechanical shock conditions beyond the limits advised in the product specification section of the catalog.

  10. Capacitor mounting
    (1) For the SMD type capacitor, design the copper pads on the PC board in consistent with the catalog or the product specification
    (2) For radial capacity ors, design the terminal holes on the PC board to fit the terminal pitch of the capacitor.

  11. Leakage current
    Thermal stress from soldering and mechanical stress from transportation may cause the leakage current to become large. In such a case, leakage current will gradually decrease by applying voltage less than or equal to the rated voltage at a temperature within the upper category temperature. In close conditions to the upper category temperature, the nearer the applied voltage to the rated voltage, the faster the leakage current recovery speed is.

◆ Mounting precautions
  1. Note
    (1) For the surface mount capacitor, design the copper pads on the PCB in accordance with the catalog or the product specification.
    (2) For radial capacitors, design the terminal holes on the PCB to fit the terminal pitch of the capacitor.
    (3) Mount after checking the capacitance and the rated voltage.
    (4) Mount after checking the polarity.
    (5) Do not apply excessive external force to the lead terminal and the CP-CAP itself.
    (6) Ensure that the soldering conditions meet the specifications recommended by CapXon. Note that the leakage current may increase due to thermal stresses that occur during soldering, etc. Note that increased leakage currents gradually decrease when voltage is applied.

  2. Soldering using a soldering iron:
    (1) The soldering conditions (temperature and time) are within the ranges specified in the catalog or product specifications.
    (2) The tip of the soldering iron does not come into contact with the capacitor itself.

  3. Flow soldering
    (1) Do not dip the body of a capacitor into the solder bath only the terminals. The soldering must be done on the reverse side of PCB.
    (2) Soldering conditions (preheat, solder temperature and dipping time) should be within the limits prescribed in the catalog or the product specifications.
    In regards to flow soldering, be sure to solder within the following conditions.
    Temperature Duration Flow number
    Preheating 120℃ or less (ambient temperature) 120 sec. or less 1 time
    Soldering conditions 260+5℃ or less 10+1 sec. or less Twice or less
    (3) Do not apply flux to any part of capacitors other than their terminals.
    (4) Make sure the capacitors do not come into contact with any other components while soldering.

  4. Reflow soldering
    (1) Soldering conditions (preheat, solder temperature and soldering time) should be within the limits prescribed in the catalogs or the product specification.
    (2) The heat level should be appropriate. (Note that the thermal stress on the capacitor varies depending on the type and position of the heater in the reflow oven.)
    (3) Vapor phase soldering (VPS) is not used.
    (4) Except for the surface mount type, reflow soldering must not be used for the capacitors.
    (5) In the case of reflow soldering, capacitive static electricity may decrease after soldering even when the soldering conditions are within the required values.
    (6) Recommended reflow condition of SMD type.
    Voltage range Preheat Time maintained
    above 200℃
    Time maintained
    above 230℃
    Peak temp. Reflow
    number
    2.5 to 10V 150 to 180℃120 sec. max. 90 sec. max 60 sec. max 260℃max only 1 time
    250℃max twice or less
    16 to 35V 90 sec. max. 50 sec. max. 250℃max only 1 time
    80 sec. max 50 sec. max. 240℃max twice or less
    50 to 100V 70 sec. max 30 sec. max. 240℃max only 1 time
    Note :
    1) All temperatures are measured on the topside of the Al-case and terminal surface.
    2) The second reflow soldering shall be applied after the temperature of capacitors decreases down to the room temperature.
    The leakage current value may increase(from a few μA to a few mA) even within the above conditions. When the CP-CAP is used in a DC circuit, the leakage current will decrease gradually through self-recovery after voltage is applied. If your reflow profile deviates from the above conditions for mounting the CP-CAP, please consult with CapXon.

  5. Handling after soldering
    Do not apply any mechanical stress to the capacitor after soldering onto the PCB.
    (1) Do not lean or twist the body of the capacitor after soldering the capacitors onto the PCB
    (2) Do not use the capacitors for lifting or carrying the assembly board.
    (3) Do not hit or poke the capacitor after soldering to PCB. When stacking the assembly board, be careful that other components do not touch the aluminum electrolytic capacitors.
    (4) Do not drop the assembled board.

  6. Washing the PCB
    (1) Do not wash capacitors by using the following cleaning agents. Solvent resistant capacitors are only suitable for washing using the cleaning conditions prescribed in the catalog or the product specification.
    In particular, ultrasonic cleaning will accelerate damage to capacitors.
    • Halogenated solvents; cause capacitors to fail due to corrosion.
    • Alkali system solvents; corrode (dissolve) an aluminum case.
    • Petroleum system solvents; cause the rubber seal material to deteriorate.
    • Xylene; causes the rubber seal material to deteriorate.
    • Acetone; erases the markings.
    (2) Verify the following points when washing capacitors.
    • Monitor conductivity, PH, specific gravity and the water content of cleaning agents. Contamination adversely affects these characteristics.
    • Be sure not to expose the capacitors under solvent rich conditions or keep capacitors inside a closed container. In addition, please dry the solvent sufficiently on the PC board and the capacitor with an air knife (temperature should be less than the maximum rated category temperature of the capacitor) for 10 minutes. Aluminum electrolytic capacitors can be seriously and catastrophically damaged by halogen ions, particularly by chlorine ions, though the degree of the damage mainly depends upon the characteristics of the electrolyte and rubber seal material. When halogen ions come into contact with the capacitors, the foil corrodes when a voltage is applied. This corrosion causes an extremely high leakage current which results venting and an open circuit.

◆ Storage
The following conditions for storage are recommended.
(1) Store capacitors in a cool, dry place. Store at a temperature between 5 and 35℃, with a humidity of 75% or less. SMD products are sealed in a special laminated aluminum bag. Use all capacitors once the bag is opened. Return unused capacitors to the bag, and seal it with a zipper.
(2) Store the capacitors in a location free from direct contact with water, salt water, and oil.
(3) Store in a location where the capacitor is not exposed to toxic gas, such as hydrogen sulfide, sulfurous acid, nitrous acid, chlorine or chlorine compounds, bromine or other halogen gases, methyl bromide or other halogen compounds, ammonia, or similar.
(4) Store in a location where the capacitor is not exposed to ozone, ultraviolet radiation, or other radiation.
(5) It is recommended to store capacitors in their original packaging wherever possible.


■ Screw
1.Guide of Aluminum Electrolytic Capacitors.
1.1 Construction of Capacitors.
When voltage V is applied between both conducting electrodes place, a certain amount charge Q will be stored in dielectric surface by a proportional relative voltage. The proportional constant C is designating the ability of the capacitor store energy in electric field. The basic construction is as Figure 1:

Figure 1

Formula of Capacitance of Capacitor
  1. C =ε0 *ε* A/d
  2. C : Capacitance (F)
  3. ε0: Absolutely Permittivity (=8.85*10^ -12 F/m)
  4. ε : Relative Permittivity
  5. A : Surface of Capacitor Electrode (m2)
  6. d : Space of Electrode (m)

The relative dielectric constant of the aluminum oxide membrane is 7 to 8, in order to obtain a larger capacitance, A
surface area A can be increased or decreased thickness B.
Electrolytic capacitor comprising of two conductive electrodes, an anode (positive foil) and cathode (negative foil) electrodes. An insulating layer is requested to separate both electrodes. Anode if formed by an enlarged surface area of aluminum foil, Oxide membrane (Al2O3) will become an insulating layer on the foil Surface. Compared with other material of capacitors, cathode electrode is in charge of conductive liquid, so called electrolyte. Cathode foil is in charge of passing current to the electrolyte.
Figure 2 Cutting Construction of Aluminum Electrolytic Capacitor.

Figure 2

1.2 Equivalent Circuit of Capacitor
Figure 3: Electrical Equivalent Circuit of Aluminum Electrolytic Capacitor

Figure 3

  1. R1: Resistance of Terminal and Electrode
  2. R2: Resistance of Anode Oxide Layer and Electrolyte
  3. R3: Insulation Resistance of Defective Cathode Oxide Membrane
  4. D1: Oxide Semiconductor of Cathode Oxide Membrane
  5. C1: Anode Foil Capacitance
  6. C2: Cathode Foil Capacitance
  7. L: Inductance by Terminals and Electrodes.

1.3 Structure of Aluminum Electrolytic capacitor
Winding of Element




2.Definitions of Electrical Parameters
2.1 Voltage
  1. 2.1.1 Rated Voltage
    Rated voltage means DC voltage and covering the peak voltage value (including pulse voltage) which may be applied continuously to a capacitor in the specified temperature range.

  2. 2.1.2 Operating Voltage
    Operating voltage is covering applied continuously rated voltage to a capacitor (including superimposed AC voltage) within specified temperature range.

  3. 2.1.3 Surge Voltage
    Surge voltage is the maximum voltage which applied to the capacitor value in a short period. Surge voltage is defined by JIS C 5101 as below:
    1. VR ≤ 315 V : VS= 1.15 multiple VR
    2. VR > 315 V : VS = 1.10 multiple VR

  4. 2.1.4 Ripple Voltage
    Voltage applied is a combination of DC and AC voltage in many product applications. Please note the following:
    DC and AC voltage superimposed voltage value must less than rated voltage
    Reverse voltage is not allowed. Applied ripple current must less than rated ripple current

  5. 2.1.5 Recovery Voltage
    Recovery voltage is after the capacitor be discharging, a voltage between 2 terminals will be appear after some times.
    Once recovery voltage is present, sparking may scare the operators during assembly, and low voltage components may also be affected. To prevent this kind of affection, use a 100Ω~1KΩ resistor to discharge the voltage and covered with a tin foil with short-circuit on 2 terminals.

2.2 Capacitance
  1. 2.2.1 AC/DC Capacitance
    In most product applications (e.g. filtering or coupling), is typically measuring AC impedance (considering the amplitude and phase) to get the AC capacitance value.
    AC capacitor is considering with frequency and temperature, JIS C 5101 defined the test frequency of 100 Hz or 120Hz, test temperature at 20 °C.

  2. 2.2.2 Calculation of Capacitance
    The capacitance of anode foil dielectric portion can be calculated by the following formula:

    ɛ: Relative Permittivity
    A: Anode Surface of Capacitor (m2)
    d: Space of Electrode(m)

    Cc of the cathode foil is determined by the characteristics of oxide membrane. And it can be generated from a forming voltage or generated by natural growth during storage. (Typically the cathode foil oxide membrane acceptance voltage is less than 1V). The structure of aluminum electrolytic capacitors, Ca and Cc are connected together by series, so the total capacitance of the capacitor can be calculated by the following formula:

  3. 2.2.3 Rated Capacitance
    Rated capacitance is a value by designed and marked on the capacitor.

  4. 2.2.4 Tolerance of Capacitance
    Capacitance tolerance is the deviation from the scope of the actual rated capacitance distribution of the capacitor.
    Usually the tolerance of the standard is +20% (M), however, a tolerances +10% (K), and other special requirements of the capacitor tolerance can be also manufactured.

  5. 2.2.5 Temperature Characteristics of Capacitance
    The capacitance of aluminum electrolytic capacitor will be affect with different temperature, the viscosity of electrolyte increased thus reducing the conductivity and capacitance when the temperature is decrease. The typical characteristic is as Figure 4:

    Figure 4
    Cs Reference value by temperature characteristic at 20°C and 120 Hz


  6. 2.2.6 Frequency Characteristics of Capacitance
    Capacitance is about to the temperature and the test frequency. As the test frequency increases, the capacity decreases. Typically frequency characteristic curve is as Figure 5.

    Figure 5
    Capacitance C: Versus Frequency f: Typical Behavior


2.3 Dissipation Factor (Tan δ), DF Value
Dissipation factor is the ratio of equivalent series resistance (ESR) to the capacitive reactance (1/ωC) in the equivalent series circuit. Aluminum electrolytic capacitors simplified equivalent circuit is as Figure 6.
Tan δ and 1/ωC, ESR series connection is as Figure 7 and by the following formula:

Figure 6


Figure 7


Where:
ESR at 120Hz
ω=2πf
f =120HZ
C: Series Capacitance (F)

DF (Tanδ) measured at 120Hz and 20 °C.
Tanδ becomes larger by measuring frequency increase (Figure 8), and test temperature decrease (Figure 9).

Figure 8


Figure 9


 
2.4 Equivalent Series Inductance - ESL
Equivalent series inductance represents the inductive part of the capacitors (lead terminal and internal foil). ESL is mainly affective by the frequency. The equivalent series circuit is as Figure 6.

2.5 Equivalent Series Resistance - ESR
ESR represents the losses of the capacitors. The equivalent series circuit is as figure 6. ESR is connected in series with the capacitance in the equivalent circuit. The ohm resistance of ESR is come from of electrode foil, electrolyte, the lead resistance and each internal resistance connection.
ESR decreases with increasing temperature, and also decreases with increasing frequency at low frequency.

2.6 Impedance Z
The impedance Z is the resistance which opposes the flow of alternating current in the particular frequency. It is related to capacitance and inductance which corresponds to the capacitive and inductive reactance, and also relevant with equivalent series resistance (ESR). Specific expression is as following.
XC: Capacitance CS Capacitive Reactance of 1/ωCS: 1/2πf*C
XL: Inductive Reactance ωESL of Capacitor Winding and Terminals: 2πf*ESL

A typical impedance versus frequency curve is as following. The minimum impedance appears at resonant frequency and it will be equal to the ESR at same frequency.

Figure 10 Impedance vs ESR vs Frequency

2.7 Leakage Current
When a DC voltage is applied through 2 terminals of the electrolytic capacitor, a small amount of current is allowed to flow into dielectric of oxide membrane. This small amount of current is called leakage current (LC).

2.7.1 Time and Temperature Characteristics of Leakage Current
As figure 11, there is a big leakage current (inrush current) flow through when capacitor is applied with voltage.
With time extend, the leakage current will decrease into a stable leakage current. Thus, the leakage current (LC) is presented after a few minutes when a rated voltage is applied at temperature 20°C.
Leakage current temperature characteristics is as figure 12, larger LC at high temperature; smaller LC at low temperature.

Figure 11 Time vs Leakage Current


Figure 12 Temperature vs Leakage Current


2.7.2 Voltage Characteristics of Leakage Current
The effective value between leakage current and voltage of ambient temperature as figure 13.

Figure 13 Leakage Current vs Voltage


2.7.3 Acceptance Test of Leakage Current
According to JIS-C-5101, following is the formula of leakage current test value after 5 minutes rated voltage applied at temperature 20 °C.



2.7.4 The behavior of leakage current without voltage applied (non voltage storage)
Oxide membrane will be not recover thus performance reduce in a high temperature when voltage is not applied to the 2 terminals of aluminum electrolytic capacitors due to no leakage flow oxygen ions into anode foil.
The leakage current will be rise back when a long time store with non voltage applied.
Please operate of capacitors over than 1 hour after an expired storage (6 months) before using in the circuit.
This action will help oxide membrane recover and can be stored again.


3.Ripple Current
3.1 General
Ripple current is alternating current which flowing through the capacitors. Each capacitor is designed by a rated ripple current which operated under a rated operating temperature to control internal temperature of capacitors. The maximum allowable ripple current depends on the ambient temperature, capacitor surface area (thermal area), dissipation factor tanδ (or ESR) and alternating current frequency.

3.2 Frequency Dependence of Ripple Current
ESR of aluminum electrolytic capacitor will effect with frequency in a fixed voltage. Thus, ripple current is also effective with frequency.
In the most product applications, more than one frequency of ripple current could be found. In this case, we have to consider RMS of ripple current because of self-heating of capacitors is come from the combination of all ripple current of frequency as formula below:


  1. Ir: RMS Value of Ripple Current
  2. If1…Ifn: RMS Value of Ripple Current at Frequency f1…fn
  3. Ff1…Ffn: Correction Factor of Ripple Current at Frequency f1….fn

  4. Where fo= Reference Frequency of Nominal Ripple Current

3.3 Temperature Dependence of Ripple Current
Capacitance of each series is given the maximum allowable ripple current under the rated temperature in category.


4.Useful Life
Useful Life (also referred to service life and operating life) is defined as the life achieved by the capacitor without exceeding the specified failure rate. The total failure or failure due parametric variation is considered to constitute the end of the useful life. Depending on the circuit design, as a failure result does not mean device failure due to parameters variation. Instead, it may consider the actual useful life will longer than the specified useful life.

Useful life is given by operating experience and accelerated aging test result. If the load is less than the rated value, useful life can be extended (E.g., lower operating voltage, current, and ambient temperature). In addition to the specified life range in category, CapXon is able to offer special useful life according to customer requested.

4.1 Load Conditions
Conditions of load useful life
  • Rated Voltage (the peak value of AC voltage superimposed on DC voltage should not be higher than rated voltage)
  • Rated Ripple Current
  • Rated Temperature

4.2 Operating Useful Life
Capacitor’s operating useful life is calculated from each series expectation useful life.
To learn more about useful life information as below:
To calculate the ratio.
To find the intersection of calculated ratio and operating temperature.
To see the useful life value from the intersection of graph curve.
Above process does not consider the frequency characteristic of ripple current. Equivalent ripple current is calculated from the frequency corresponding to the conversion factor.
The following example illustrates the calculation procedure to use the data of a capacitor of RH series
VR CR Case IR max 120Hz 105°C (A)
450 2200 63.5X120 9.2

Figure 14


E.g. 1- Calculation of Useful Life
The following values are used to determine the frequency conversion. The corresponding useful life can be calculated.
Ripple Current: 25 A
Frequency: 400 Hz
Ambient: 60°C
Equivalent ripple current at 120Hz frequency converts calculations (see RH series allowable ripple current IRC frequency)

To calculate the ratio of the actual value of the ripple current and specification values.
Ripple current ratio and ambient temperature (60°C) on the intersection of the graph says the useful life is 100,000 hours (Figure14).

E.g. 2- Calculation of Ripple Current on Aluminum Electrolytic Capacitor
In many applications, Aluminum Electrolytic Capacitors are subjected to the ripple currents of varying frequency.
Current 1: Ia1, at 400Hz RMS=20A
Current 2: Ia2, at 4 kHz RMS=16A
Ambient: 60°C
Requested Useful Life 100000 Hours
The first step is calculating equivalent 120Hz values for the 2 current values (Frequency factors given on series RHFrequency factor of permissible ripple current IRC) and the RMS value)

Calculation of Ripple Current Factor:

Ripple current ratio and ambient temperature (60°C) on the intersection of the graph says the useful life is 100,000 hours (Figure14).


5.Connection of Aluminum Electrolytic Capacitor
In some applications of Aluminum Electrolytic Capacitor, parallel connection and series connections and combination of parallel and series connections will be used.

5.1 Parallel Connection
Parallel connection: Current flows in equally through each unit are a necessary when parallel connection.

5.2 Series Connection
Series connection: Using balancing resistors to equally control the voltage distribution across each unit.
Operating voltage may exceed the specification value because of each single capacitors insulation is quite different and voltage distribution may quite irregularly. Therefore, forced balancing of voltage distribution is recommended. The balancing resistance must be equal to each other, and the resistance is requested much less than insulation resistance of capacitors. As Figure15:

Figure 15
Formula of Equation Resistance Value:
R balancing resistance = 50MΩ * μF * (1/CR)

5.3 Combination of Parallel and Series Connection
Above recommended combination gives apply both in Parallel and Series circuit. It is recommended to allocate balancing resistors to each capacitor if use balancing resistors is a must. (as Figure 16)

Figure 16


6.Climatic Conditions
6.1 Minimum Permissible Operation Temperature (Lower Temperature)
Aluminum Electrolytic Capacitors will increase DF values (or ESR values) when the operation temperature is decrease.
Aluminum Electrolytic Capacitors will define the minimum operating temperature due to both of DF and ESR values arelimited in a range for most product applications.

6.2 Maximum Permissible Operation Temperature (Upper Temperature)
Maximum permissible operation temperature is meaning the capacitors maximum operation environment temperature.
Capacitors will be un-useful if operation environment is higher than category defined.
Useful life and reliability will both increase if capacitors can be used in lower operation temperature environment.

6.3 Storage Temperature
Aluminum Electrolytic Capacitors can be stored in voltage-free under category said temperature. However, it must reduce useful life and reliability easier and accelerate leakage current value if Capacitors stored in higher temperature. The oxide membrane getting worst is the mainly reason to cause abnormal circuit when Oxide membrane repaired by a larger current suddenly. Therefore, the storage temperature should not exceed 40 °C, and suggested stored at temperature 5 °C ~ 35 °C
The effective valid date of capacitors is for 1 year, please use a series resistor in 1000Ω and rated voltage to charge for 30 minutes continuously to let inside oxide membrane regeneration if storage in a long time (over 12 months) is a necessary.

7.Maintenance
A regular inspection is recommended when screw capacitors use in industrial applications. Before inspection, make sure to turn off the power and discharge screw capacitors carefully, and do not force pressure to the terminal to avoid damage.
Inspection items as below:

7.1 Outer damage, deformation and electrolyte leakage checking.

7.2 Electrical Performance: leakage current, capacitance, DF values and other product specifications subject times.
If there is an abnormal detected, make sure the capacitor specifications to replacement and handled properly.


8.Mounting
8.1 Installation
Make sure capacitor's rated capacitance, rated voltage and polarity before installation.
Please confirmed capacitors and circuit board terminal pitch is consistent before installation. It may cause stress to internal capacitor through the terminal to cause short if the pitch is different.
Robotic force pressure and lead bending strength has to be controlled properly when automatically mounting.

Mounting Position of Screw Capacitors
To avoid screw capacitor explosion when capacitance safety vent is opened while capacitance reached a certain exhaust gas pressure, the screw capacitors should not be mounted with the safety vent upside down. Recommended mounting method is shown as Figiure17 to avoid safety vent down installation.

Figure 17
Recommended range of mounting positions

Horizontal Mounting Request
Anode terminal in upper side with safety vent in horizontal as Figure18.
Safety vent in upper side with Anode and Cathode terminal in horizontal as Figure19.

Figure 18


Figure 19

It may not damage capacitors directly but an electrolyte leakage may happen if install by other mounting methods.

8.2 Soldering
8.2.1 Before Soldering
Soldering conditions (preheat, solder temperature and immersion time, frequency) must be completed in the limited range to prevent the performance of capacitors.
When circuit board terminal pitch does not match with capacitors terminal pitch, please do not force extra pressure to capacitor when an extra treatment is necessary.
To avoid treating capacitor body with a soldering iron to prevent sleeve holes and other damage;
To avoid capacitor body dipped in soldering, solder heat will cause the capacitor damage due to internal pressure arise.

8.2.2 After Soldering
After soldering into PCB, do not external forces or pull capacitor body, to prevent the extra pressure to damage the part through the terminal into internal body to cause part short.

8.3 Cleaning Agents
Please use available cleaning agents to clean circuit boards under temperature 50°C within 5 minutes after soldering
Cleaning agent must be strictly managed, such as pollution, chlorine concentration may be increased, result to an internal capacitor corrosion.
After cleaning, must be dry immediately, to avoid cleaning agent remains between sealing portion and circuit board.
Do not use below solvents to clean the capacitance:
Halogen-containing solvents: halogen solvents penetrate (diffuse) into the internal capacitance, will cause cleaning agent decomposition reaction of free chlorine ions, react with the aluminum to cause capacitor corrosion. Alkaline solvent: corrosion aluminum case Xylene: sealing rubber oxidation Acetone: description words blur or disappear


9.Outer Sleeve of Capacitors
Outer sleeve and outer plate does not guarantee electrical insulation function, description only.


10.Marking of Capacitors
Marking Content of Screw Type:solvent.


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