Started in the year 1967 , the capacitor Division of Universal Cables Limited has completed more than thirty eight years of manufacturing power factor correction capacitors.

During the period a number of technological changes have been brought forward . Started by manufacturing paper dielectric capacitors, the manufacturing range was switched over to mixed dielectric capacitors in 1977 , followed soon after by all PP capacitors with non-PCB , non-toxic oil impregnation.

Unistar capacitors are well known in market for their superior quality and unmatched performance . The ever growing list of highly satisfied customers is a proof.

Unistar capacitors are periodically tested in National Laboratories. Following latest Test Certifications and approvals are available: 

• CPRI, Bangalore Type Test Report up to 50KVAr, 440v All PP capacitor unit. 

• ERDA, Vadodara Type Test Report up to 400 kVAr, 8.37kV capacitor unit.

• CPRI,  Bangalore Type Test Report up to 529kVAr, 12kV capacitor unit. 

• CPRI,Banglore Endurance Test Report for 200kVAr, 7.3kV capacitor unit as per IEC.

• Approved by RDSO, EL, DGS&D, MECON , etc.

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CONSTRUCTION OF UNISTAR CAPACITORS

Capacitors:- 

Unistar High Voltage Capacitors consist of element wound from high purity soft annealed aluminum foil and layers of biaxial oriented hazy polypropylene.  Aluminium foil electrode edges are folded on automatic winding machines. The elements are assembled in parallel combination to form a block giving desired capacitance and voltage rating .Connections are taken out from extended Aluminium foil by special soldering method.  After providing insulation from all sides the block is inserted in a metal container.  The leads are taken out through suitable voltage class bushings and the unit is subjected to fine vacuum drying and impregnated with highly purified non-PCB oil and then hermetically sealed.  The unit is put through series of physical, electrical&endurance tests as per the relevant standards.  The container is given acoatof red oxide primer and then two coats of finish paint of light grey enamel shade631 of IS:5.  Capacitors are made either with internal element fuses or are made suitable for external fuses as per the requirement.  Units also provided with internal discharge resistors to discharge the capacitors in less than 300 seconds to 50 volts or less,

All PP (FILM + FOIL) MediumVoltageCapacitors(400to 100OV):- 

Single layer All PPcapacitor 415/440 V and double layer All PP capacitors are manufactured with extended Aluminium foil, double hazy PP film, internal element f uses and same sophistication as high voltage capacitors.  They are electrically stronger than mixed dielectric capacitor.  Winding on fully automatic machine in ultra clean atmosphere result in long life capacitors.  The Capacitors are impregnated with PXE oil.

415/440 V MPP Capacitors:-

Vapour deposited Metallized polypropylene sheets are wound tightly together on a fully automatic winding machine fitted with memorized programme sequencer and electro pneumatic controls in an air conditioned humidity controlled and absolutely dust free room.  Special air showers have been installed so that dust particles do not hang around the winding machine.  Extremely hard elements thus formed are stabilized in drying oven, and sprayed with sophisticated spray gun, passed through automatic short clearing machine.  These sealed elements are assembled to make capacitor unit which are Routine & Type tested including special tests like endurance tests.

ADVANTAGES OF SELF HEALING MPP CAPACITORS

MPP capacitors are also called' self healing capacitors'.  In the figure below metallized PP film is shown.  Across the two aluminum coating, a voltage of 415 or 440 V is applied.  If there is an impurity (conducting particle) or a pin hole, then dielectric fails to withstand the voltage and puncture of dielectric takes place, this produces an arc between the electrodes.  High current flows through the arc which vaporizes thin coating of aluminum around failure leaving bare polypropylene film.