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MEDIUM FREQUENCY WATER COOLED CAPACITORS

General Information

Scope

Medium Frequency Water Cooled Capacitors from 1 kV up to maximum 5000 volts, to maximum 7000 kVAr and frequency up to 50 kilocycles for indoor use.

  • with dead casing, open terminal (2 bushings).
  • with live casing, open terminal (1 bushing).

Applicable Standards

  • IEC 60110-1 Capacitors for Induction Heating & Melting application.
  • IS 9251 Capacitors for inductive heat generating plants operating at frequencies between 40 and 24000 Hz
  • DIN EN 60110-1 Power Capacitor for Induction Heating Installations.
  • VDE 05650-9:1999-09

Ratings

  • Voltage: Up to 5kV
  • Output Capacity: Up to 7200 KVAr
  • Frequency: Up to 50 kHz
  • Mounting: Suitable for both Horizontal / Vertical
  • Container: Imported Embossed Aluminium sheet.
  • Construction: Live / Isolated (Dead) container

Safety

Over pressure dis-connector provided with NC contact.

Tests

Each and every Capacitor is subjected to Routine tests in accordance to IEC 60110-1.

  • Measurement of Capacitance.
  • Measurement of Dielectric Loss angle @ 50Hz.
  • Voltage test between terminals
  • Voltage test between terminals & container
  • Sealing Test

Features

  • Low losses < 0.8 watts per kVAr
  • World Class Raw Materials
  • Manufactured in state of art infrastructure
  • Volume Optimized and highly Reliable
  • Trouble free Long life performance
  • Environmentally friendly.

Quality Management System

ISO 9001 accredited byTUV.

Safety Regulations

When installing the equipment, relevant IEC or VDE recommendations shall be observed.

Quality management system

ISO 9001, BS 5750 Qualifications EDF (HN 54-5-05), CSA

Altitude

Capacitors are designed to operate at altitudes not exceeding 1500 mtrs.

Impregnant

The capacitors are impregnated with a NON-PCB based fluid which is Jarylec C-1 01. This dielectric fluid is environmentally acceptable, eliminates health and environment hazards.

Dielectric

An imported all film dielectric is used and consists of polypropylene in the form of bi-axially oriented film, hazy on both sides, and in 2 or 3 layers with end and edge folded aluminum foil as electrodes.

Dielectric losses

Dielectric losses@ 50 Cis in fresh condition are approx. 0.2 to 0.3 watts / kvar up to 5 KHz, and 0.5 watts / Kvar up to 50 KHz and reduce after 500 operating hours to a stable state. The dielectric losses, depending on capacitor design, shall be added to losses caused by:

  • Internal discharge resistors
  • Internal connections

Permissible Overloads

Maximum permissible voltages Capacitors are designed for operation at voltage levels according to the following table.

The amplitudes of the over voltages that can be tolerated without
significant deterioration of the capacitor depend up on the duration, the total number and the capacitor temperature.

Discharging

Each capacitor unit shall be provided with means of discharging to 75V or less.

Switching over voltages

The residual voltage on a capacitor prior to energization shall not exceed 1 0% of the rated voltage.

Maximum permissible currents

Capacitor units will be suitable for continuous operation at an r. m. s current of 1.30 times the current that occurs at rated sinusoidal voltage and rated frequency, excluding transients.

Manufacturing and Quality Control

Imported bi-axially oriented Double hazy Polypropylene film and 99.9% pure aluminum foil are used as dielectric and electrode. Wrinkle free winding of the elements is carried in an Class 100 environment on a Semi Automatic winding machine with edge and end folding of the aluminum foil. This is to eliminate overvoltage stress at the edges of the buried area of the foil.

Each wound element is tested for dry DC Overvoltage with stand for pin holes and adequacy of margins between AI foils. Numbers of elements are interconnected in series - parallel to achieve the desired capacitance and designed voltage rating of the Capacitor.

The dry pack is wrapped with several layers of high quality insulating paper before inserting it into a pre treated / degreased aluminum container and the top lid is welded by semiautomatic Pulsed TIG welding machine.

The aluminum Sheet used for fabricating containers is imported, manufactured of a special alloy with its surface embossed. All metal parts copper and brass are silver brazed to ensure homogeneous joint.

Porcelain bushings of desired BIL are leak proof fitted on the lid as required. The terminals are manufactured from extruded brass and the water cooling pipe is of 99.99% pure electrolytic grade annealed copper and pressure tested for leaks before fitting on the pack. On specific request of client, imported over pressure switches are also fitted on the Capacitors.

All the joints are tightened with torque wrench and are locked to ensure they remain perfectly tight always. The capacitors are then loaded in a PLC controlled autoclave for uniform heating @85°C and drying under vacuum of 0.001 torr for a given period. After confirming the quality of drying by precision online monitoring instruments, the capacitors are then impregnated under vacuum with highly purified and degassed Jarylec C- 1O1. The capacitors are then subjected to all routine tests in accordance to IEC-60110-1.

 

Un (V r.m.s) Maximum Duration Observation
1.00 Continuous Highest average value during any period of capacitor energization
1.10 8 h in every 24 h System voltage regulation and fluctuations.
1.15 min in every24 h System voltage regulation and fluctuations.
1.20 5 min Voltage rise at light load
1.30 1 min -

Life Expectancy

Based on the state of art plant& machinery, quality of raw materials used, manufacturing under strict quality control and process using precision on line instruments, and elevated over voltage test results under extreme temperatures, capacitors are assured of minimum 20 years life.

Electrical Tests

Each and every capacitor is subjected to Routine tests in accordance to IEC60110-1.

  • Measurement of Capacitance.
  • Measurement of Dielectric Loss angle @ 50Hz.
  • Voltage test between terminals 4 Vn for 10 secs.
  • Voltage test between terminals& container 2.15 Vn.
  • Sealing Test @ 80°C for 2hrs.