1. HOW TO ORDER

SERIES           RATED VOLTAGE        CAPACITANCE         SIZE        PACKING      TOLERANCE

a) SERIES :  Refer Table of Contents.

b) RATED VOLTAGE :

Voltage in volts (V) is represented by a two digit code showing the real working voltage indicated as follows.

Note :

1.  Contact Factory for miniaturized 500 V DC Radial, Snap-In type Capacitors.

2.  LA1, LA2 Series Capacitors are replaced with high reliability IL1, IL2 series of capacitors.

3.  New Products developed :

a) 3 Terminal Capacitors - TUB 5

b) 4 Terminal Capacitors - IS2-4T

c) -550C to +1050C Capacitors of 63 WV and below

Refer our Screw Terminal Capacitor catalogue for Professional Grade series of Capacitors.

APPLICATION GUIDELINES

Circuit Design

Ensure that operational and mounting Guidelines specified in the Catalogue and Data Sheets are followed while using Aluminium Electrolytic Capacitors.

1.1   Operating Temperature and Frequency

Electrical Parameters of Electrolytic Capacitors are normally specified at 200C temperature and 120Hz frequency. These parameters vary with changes in temperature and frequency. Circuit designers should take these changes into consideration while designing the circuit.

1.1.1   Effect of operating temperature on electrical parameters

a)  At higher temperature,  Leakage Current  and  Capacitance increases  while Equivalent Series  Resistance  (ESR) decreases.

b) At  lower  temperature,  Leakage  Current  and  Capacitance decreases  while Equivalent  Series  Resistance  (ESR) increases.

1.1.2   Effects of frequency on electrical parameters

a) At higher frequencies, Capacitance and Impedance decrease while tan d increase.

b) At lower frequencies, Ripple Current Generated Heat will rise due to an increase in

Equivalent Series Resistance (ESR).

1.2.  Operating Temperature and Life Expectancy in accordance with useful life of Capacitance

1.2.1. Life is affected by the increase in temperature. Generally, each 100C a rise in temperature will reduce the useful life by 50%. Use capacitors at the lowest possible temperature below the maximum rated temperature to get optimum specified results.

1.2.2.  If  operating  conditions  exceed the maximum rated limit, the electrical parameters  deteriorate rapidly  causing  irreversible damage to the capacitors. Check  for  maximum  capacitor  operating  temperature  including ambient temperature, internal capacitor temperature rise due to ripple current and the effect of radiated heat from power source.

A quick reference capacitor guide for estimating life is as given below

A quick reference capacitor guide for estimating  life is as given below

☛ Useful Life Estimate Quick Reference Guide

                                   1. 850C2000h

                                                                  2. 1050C1000h

☛ Failure rate curve

1.3 Factors Effecting life expectancy

The following misapplication will cause rapid deterioration to capacitor electrical parameters. In addition to rapid heating and gas generation within the capacitor pressure relief vent will operate and result in leakage of electrolyte.

1.3.1 Reverse Voltage

DC capacitors have polarity. Verify correct polarity before insertion. For circuits with changing or uncertain polarity, use DC Bi-polar / Non-polar capacitors. DC Bi-polar/Non-polar Capacitors are not suitable for use in AC circuits.

1.3.2 Charge/Discharge Applications

Standard capacitors are not suitable for use in repeating charge/ discharge applications. For charge/ discharge applications specially designed Capacitors are to be used.

1.3.3 Over Voltage

Do not apply voltage exceeding the maximum specified rated voltage. Voltage up to the surge voltage are acceptable for very short duration only. Ensure that the sum of the DC voltage and the superimposed AC ripple peak voltage does not exceed the rated voltage.

1.3.4 Ripple Current

Do not apply ripple currents exceeding the maximum specified value. For high ripple current applications, use a capacitor designed for high ripple currents or contact factory with your requirements.

1.4    Using Two or More Capacitors in Series or Parallel

1.4.1   Capacitors Connected in Parallel

Due to difference in ESR value of individual capacitors the ripple handling of the capacitors also vary. Careful design of the Circuit can minimize the possibility of excessive ripple current coming to a capacitor.

1.4.2   Capacitors Connected in Series

Due  to  difference  in  DC  leakage  current  in  the  capacitors connected in series the voltage imbalance shall occur. To avoid, suitable shunt resistors may be provided in the circuit.

1.5    Capacitor Mounting Considerations

1.5.1 Double Sided Circuit Boards

External  wiring  of  the  components  to  be  so  done  if  necessary that the extra solder is not collected under wiring which cause short circuit of the capacitors.

1.5.2   Circuit Board Hole Positioning

The dia of the hole for positioning the capacitor to be designed such  that  excess  solder  is  not passing  through  the  hole  and damaging the insulating sleeve.

1.5.3   Circuit Board Hole Spacing

2.     Capacitor Handling Techniques

2.1  Considerations Before Using

a)    Capacitors have a finite life. Do not reuse or recycle capacitors from used equipment.

b)    Transient recovery voltage may be generated in the capacitor due to dielectric absorption. If required, this voltage can be discharged with a resistor of 1 KΩ.

c)    Capacitors stored for long periods of time may exhibit an increase in leakage current. This can be corrected by gradually applying rated voltage  in series through a 1KΩ resister.

d)    If  large  capacitors  are  dropped,  they  can  be  damaged mechanically or electrically. Avoid using dropped capacitors.

e)    Dented or crushed capacitors should not be used. This shall result in short circuit / reduced life.

2.2   Capacitor Insertion

a)     Verify the correct capacitance and rated voltage of the capacitor.

b)       Verify the correct polarity  of the capacitor before inserting.

c)     Verify the correct hole spacing before insertion  to avoid stress on the terminals.

d)     Please ensure that while components are auto inserted, handling and lead trimming are carried out  without developing stress at the point  where  the  lead  is  entering  the seal  (rubber  bung)  of  the capacitor.

2.3   Manual Soldering

a)     Please ensure soldering time is less than 3 sec. and temperature not exceeding 3500C.

b)     If the capacitor leads are having a pitch different to that of PCB the leads are to be formed to match the PCB, pitch in such a way that no stress is developed on the capacitor.

c)    If  a  soldered  capacitor  is  to  be  removed  and  reinserted,  avoid excessive stress coming to the capacitor leads.

2.4  Soldering Considerations

a)    Observe proper soldering conditions (temperature, time, etc.) Do not exceed the specified limits.

b)    Rapid temperature rises during the preheat operation and resin bonding operation can cause  cracking of the capacitor vinyl sleeve. For temperature curing, do not exceed 1500c for a maximum time of 2 minutes.

2.5  Capacitor Handling after Soldering

a)    Avoid bending of the capacitor after soldering to prevent excessive stress on the lead wires where they enter the seal.

b)     Do  not  use  the  capacitor  as  a  handle  when  moving  the  circuit board assembly.

c)     Avoid striking the capacitor after assembly to prevent failure due to excessive Stress

2.6   Circuit Board Cleaning

a)     Circuit boards can be immersed or ultrasonically cleaned using suitable  cleaning  solvents for up to  5  minutes  and  up  to  600C maximum temperatures.  The boards should be thoroughly rinsed and dried.

b)    Avoid using the following solvent groups

☛   Halogenated  cleaning  solvents  :  Halogenated  Solvents  can permeate  the  seal and  cause  internal capacitor  corrosion  and failure 1-1-1 trichloro ethane should never be  used on Aluminium Electrolytic  Capacitor.

☛   Alkali solvents : could attack and dissolve the aluminium case.

☛   Petroleum based solvents : shall result deterioration of the rubber seal.

☛   Xylene : Deterioration of the rubber seal could result.

☛   Acetone : Removal of the ink markings on the vinyl sleeve could result. It will spoil the sleeve also.

c)   A thorough drying after cleaning is required to remove residual cleaning solvents which may be trapped between the capacitor and the circuit board. Avoid drying temperature which exceed the maximum rated temperature of the capacitor.

d)  Monitor the contamination levels of the cleaning solvents during use by electrical conductivity, pH, specific gravity, or water content. Chlorine levels can rise with contamination and adversely affect the performance of the capacitor.

3.   Precautions for using capacitors

3.1  Environmental Conditions

Capacitors  should  not  be  stored  or  used  in  the  following environments.

a)   Temperature exposure above the maximum rated or below the minimum rated temperature of the capacitor.

b)   Direct contact with water, salt water, or oil.

c)   High  humidity  conditions  where  water  could  condense  on  the capacitor.

d)   Exposure  to  toxic  gases  such  as  hydrogen  sulphide,  sulphuric acid, nitric acid, chlorine, or ammonia.

e)   Exposure to ozone radiation, or ultraviolet rays.

f)   Vibration and shock conditions exceeding specified limit.

3.2 Electrical Precautions

a)  Avoid  touching  the  terminals  of  the  capacitor  to  avoid  electric shock. The exposed aluminium case is not insulated and could also cause electric shock if touched.

b)   Avoid short circuiting of the capacitor terminals with conductive materials including  liquids such as acids or alkaline solutions.

4.  Long Term Storage

Leakage current of a capacitor increases with long time storage. The aluminium oxide film deteriorate as a function of temperature and time. If used without conditioning, an abnormally high current will be required to restore the oxide film. This current surge could cause the circuit or the capacitor to fail. Capacitor should be conditioned by applying rated voltage in series with a 1KΩ, current limiting resistor for a period of min. 30 minutes.