Basic Material For Construction Of Start Capacitors :
Etched and Formed aluminium Foil :
Etched and Formed aluminium electrode foil is a ANODE FOIL, normally of 90 micron to 100 micron thickness. It is a super purity aluminium foil, 99.99% pure Al , having specific metallurgical standards, cold drawn. This foil is etched with electro-chemical process to increase the surface area of the foil. After etching, foil is formed at a specific DC voltage as per the required forming voltage for design of Start Capacitor. ARISTO is importing the etched and formed foils from M/S. Becromal S.p.A., Italy and from M/S. SATMA, France.
Cathode etched aluminium foil :
Etched Cathode foil is unformed electrode foil, normally of 20 microns to 50 microns thickness. It is a super purity aluminium foil, 99.8% Al, having specific metallurgical standards, cold drawn. ARISTO is importing cathode foil from M/S. Becromal S.p.A, Italy and M/S. SATMA, France.
Tab foil :
It is a super purity plain aluminium foil, 99.99% Al, formed at specific voltage, known as Tab foil, normally of 150 micron to 200 microns thickness, annealed before forming.
Electrolytic Tissue Paper :
Electrolytic Tissue Paper is a electrical grade paper, absolutely necessary to guarantee essential electrical and mechanical quality parameters. It is normally of 60 micron thickness of a specific density, tensile strength, dielectric strength, conductivity, porosity and chloride free status. Supporting tissue paper of 15 micron is used as per the design of Capacitor. Both papers are imported from M/S. SPO Spezialpapierfabric, Germany and M/S. NKK, Japan.
It is a specific electrolyte design for high working voltage aluminum electrolytic capacitor with a technique, which is required for capacitors of high performance and reliability. More precisely, it is a Mono Ethylene Glycol based paste, consist ammonium borate. The water content is removed with our own technique, in order to prevent deterioration of dielectric oxide film and to increase thermal stability. The chemicals such as corrosion inhibitors, surface acting agents, gas absorbents and voltage resistance increasing agents added to make the paste for high conductivity and high voltage resistance.
Rubber molded Bakelite disc :
It is a special top for mounting the lug terminals, with a specific center distance taken for lug riveting. Bakelite disc is having a round hole covered by thin layer of rubber to have a vent hole function and pass the gases from the inner aluminum can.
Lug terminal and Rivet :
Lug terminals of ‘L’ type, with a specific opening for wire soldering, is riveted on the Bakelite disc with super purity aluminum rivets.
Wire, Solder, Shrinkable sleeve, PP Can, wire sleeve, Disc, bitumen etc. :
Electrolytic Start Capacitors are of Double aluminum Can with wire and lug terminal type. For Double can capacitor, wire of 32 strings, 36 number and 1 sq.mm, as per IS:694 is used. Flux coated 60/40 solder is used. Shrinkable sleeve is used for lug terminal type capacitors. PP can is used as a inner can to avail safety. Bitumen is used to fix up inner can. Wire sleeve is kept to protect the wires through rubber groove mates. Upper disc is made of HIP material with the capacitor specifications embossed on the top.
Manufacturing process :
Aristo has its own design of Electrolytic Start Capacitor. This design consist of two formed electrode (Anode foils ) and one unformed electrode ( Cathode foil ), constituting a series circuit, formed – unformed – formed electrode foils. Two formed foils wound with absorbent electrolytic tissue paper separator and unformed electrode foil and impregnated in electrolyte and encased. The impregnated wound is encased in aluminum can. These elements are charged for 30 hrs. at 70 degree centigrade. After curling the Bakelite disc, wire is soldered and the aluminum can is put in the outer aluminum can with supporting PP can and marking disc is curled. Marking sticker is put on the outer can. Packing of 25 pcs. in each box is done.
Construction Of Start Capacitors :
Capacitors are suitable for duty cycle at 20 starts per hour maximum, each start of not more than 3 seconds duration, at rated voltage, followed by 177 seconds off duration. For evaluating the life test, capacitors are tested at duty cycle 0.0167 i.e. one time per minute one second on and 59 seconds off for minimum number of 40,000 starts.
At the point of normal lead connection, terminals will withstand a force of 2 Kgs. Or 5 pounds applied gradually in any direction for a period of one minute. There will be no loosening of the terminals or damage to the terminal or seal.
Capacitors are designed to withstand a 2000 Volts RMS 50- cycle voltage applied for 5 seconds between terminals and case without breakdown or flashover. A special design is made by putting additional PP can to assure more safety only for the capacitors made for M/S. KIRLOSKAR COPELAND LTD.
The normal shelf life expectancy for Electrolytic Start capacitors is typically in excess of 5 years when stored in ambient temperatures not exceeding 40 degree centigrade. Capacitor should be recharged by applying rated voltage for 2 to 3 seconds. This may be repeated three times.
Some specialized applications require that the motor start capacitor be discharged prior to the closing of the start switch. This minimizes the shock hazard, switch bounce noice, and peak contact currents. The resistor used to discharge the capacitor is 15K +/- 20% 2 Watt, is large enough so as not to significantly increase the power factor and small enough to ensure discharging the capacitor within the time required. This design is specially made for M/S. KIRLOSKAR COPELAND LTD.
Capacitors will have the following minimum marking.: Manufacturer’s Name (ARISTO) and /or Symbol Capacitance ( Min – Max Mfd ) Rated Voltage and frequency Temperature range and Duty Cycle