POWER CAPACITORS

HEAVY DUTY CAPACITORS

“SARDA” heavy duty power capacitors are specially designed to meet the requirements of varying loads in industries having higher over currents/voltages and also harmonics. In this design the out put of KVAr value remains the same however there is phenomenal reduction in stress per module as these modules are doubled and connected in series.

Heavy-duty power capacitors are meant to replace conveniently & cost effectively the conventional mixed dielectric/film-foil capacitors.

These Capacitors have been designed to suit fluctuating load conditions and withstand over-voltage and over-currents within permissible limits. These Capacitors are stronger than standard type to withstand required dielectric stress which varies non-linearly.

Heavy Duty Power Capacitors
Rated

KVAr

Length Width Height
1 150 60 190
2 185 65 215
3 185 65 215
4 185 65 215
5 185 65 315
6 185 65 315
7 210 75 315
8 210 75 315
9 210 75 315
10 220 80 425
12 220 80 425
12.5 220 80 425
15 250 90 425
20 220 160 425
25 220 160 425
  • Rolling Mills
  • Cement & Sugar Plants
  • Induction Furnaces (Power Frequency)
  • Welding Systems
  • Rectifier Loads
  • Power Industries Etc.
  • Higher dielectric thickness
  • Over voltage and current carrying capacity
  • Modular design
  • Very low temperature rise
  • Longer life
  • In rush current limiting inductor coils are used for longer life of Capacitors

To increase the efficiency of the electrical system, power factor is improved by providing power capacitors in the electrical system. Some of the major advantages of using power capacitors are:-

  • Reduction in electrical bill.
  • Improvement in voltage regulation.
  • Reduction of power losses
  • Meet statutory requirement & avoid penalty.
  • Advanced vapour coating techniques involving high degree of purity of metal, coupled with heavy edge gives added advantages to metallised Polypropylene film of self healing type to handle higher currents and withstand the electrical surges that are predominantly observed in the power systems.
  • Effects of harmonic currents are minimized by using suitable filter networks in conjunction with these capacitors which can be supplied on specific request.
  • In rush current limiting inductor coils are used for longer life of Capacitors.
  • Low energy consumption due to low watt i.e. <0.5 watt/KVAr.
  • Higher insulation properties and temperature withstanding Capability.
  • Modular design: For easy maintenance as the modules are replaceable.
  • Explosion Proof Design: By using soft Epoxy / PU Resin, pressure developed due to any internal fault of the Capacitor will disconnect the electrical connection of the module and safe guard the nearby equipment.
  • S Box (Housing) for Capacitor is provided with Louvers for free air ventilation thereby keeping operation temperature at lower levels and increasing life of the Capacitors.
  • KVAr ratings are from 1 KVAr to 50 KVAr. Banking of KVAr units is also undertaken by us for higher KVAr rating requirements.
IMPORTANT FACTORS WHICH INFLUENCE QUALITY AND RELIABILITY OF POWER FACTOR CORRECTION CAPACITORS AT THE END USERS PLACE
  • Immediately after receipt please check the capacitor and ensure that they are in good condition without any external damages during transit.
  • Please ensure that the capacitor terminals are tight & proper while connecting to the load. Any loose contact at the terminals may result in heating and premature failure of capacitors.
  • Ensure proper grounding of capacitor before energising it.
  • Check discharge resistors connected across the terminals are intact, capacitors must be discharged fully before handling it. Do not charge capacitor without discharge resistor.
  • Energise the capacitor and measure voltage & current using a clamp meter in all the phases.
  • Proper current rating MCB is recommended in order to avoid over current to the capacitor which may cause fire risk.
  • Automatic switching of power capacitor in sequence shall be such that already energised capacitor shall have sufficient time delay circuit for discharge before it is subjected to another re-striking operation. This is an important aspect, which if proper care is not taken may result in over-voltage condition, increasing the risk of capacitor being subjected to high voltage stress level and there by the dielectric insulation breakdown.
  • Harmonic distortions in electrical systems are commonly present in loads like thyristor controlled DC drives, rectifiers, arc welding machines, etc. Harmonic filters reduces harmonic distortion to avoid higher current across the capacitor terminals resulting in over heating the capacitor.
  • Switch ‘off’ capacitors when inductive loads are not in use. Care must be taken to see that the capacitors shall not draw any current from the source which results in leading power factor which is not recommended since the reactive power compensation exceeds more than what is needed.
  • When star delta starters for higher rating inductive motors are switched on, take care so that capacitors are switched on when motors are running in delta connection only. This can be done by making use of delay timer which can switch on the contactor and capacitor.
INSTRUCTIONS FOR INSTALLATION AND MAINTENANCE OF L.T POWER CAPACITORS
  • Ensure proper rating of required KVAr is connected at load points.
  • Adequate fuse ratings / cables switch gears shall be used.
  • Firm fixing of capacitors along with cable lugs of appropriate size shall be used.
  • Earthing should be done properly to avoid accidental leakage current.
  • Repeated switching without sufficient time delay shall be avoided.
  • Discharge resistors needs periodic checking in order to avoid shock hazards.
  • Periodic checking of current in each phase is essential to keep track of capacitor condition.
  • Switch off power capacitors under light load or no load conditions.
  • All capacitors must be discharged before handling.

 

RECOMMENDED CAPACITOR RATING FOR DIRECT CONNECTION TO INDUCTION MOTORS

To improve Power Factor to 0.95 or better at all loads
Capacitor rating in KVAr when motor speed is Capacitor rating in KVAr when motor speed is

MULTIPLYING FACTOR FOR CALCULATING THE SIZES OF CAPACITOR FOR POWER FACTOR IMPROVEMENT
To improve Power Factor to 0.95 or better at all loads
Capacitor rating in KVAr when motor speed is Capacitor rating in KVAr when motor speed is
Motor 3000 1500 1000 750 600 500 Motor 3000 1500 1000 750 600 500
H.P r.p.m r.p.m r.p.m r.p.m r.p.m r.p.m H.P r.p.m r.p.m r.p.m r.p.m r.p.m r.p.m
2.5 1 1 1.5 2 2.5 2.5 105 22 24 27 29 36 41
5 2 2 2.5 3.5 4 4 110 23 25 28 30 38 43
7.5 2.5 3 3.5 4.5 5 5.5 115 24 26 29 31 39 44
10 3 4 4.5 5.5 6 6.5 120 25 27 30 32 40 46
12.5 3.5 4.5 5 6.5 7.5 8 125 26 28 31 33 41 47
15 4 5 6 7.5 8.5 9 130 27 29 32 34 43 49
17.5 4.5 5.5 6.5 8 10 10.5 135 28 30 33 35 44 50
20 5 6 7 9 11 12 140 29 31 34 36 46 52
22.5 5.5 6.5 8 10 12 13 145 30 32 35 37 47 54
25 6 7 9 10.5 13 14.5 150 31 33 36 38 48 55
27.5 6.5 7.5 9.5 11.5 14 16 155 32 34 37 39 49 56
30 7 8 10 12 15 17 160 33 35 38 40 50 57
32.5 7.5 8.5 11 13 16 18 165 34 36 39 40 51 59
35 8 9 11.5 13.5 17 19 170 35 37 40 42 53 60
37.5 8.5 9.5 12 14 18 20 175 36 38 41 43 54 61
40 9 10 13 15 19 21 180 37 39 42 44 55 62
42.5 9.5 11 14 16 20 22 185 38 40 43 45 56 63
45 10 11.5 14.5 16.5 21 23 190 38 40 43 45 58 65
47.5 10.5 12 15 17 22 24 195 39 41 44 46 59 66
50 11 12.5 16 18 23 25 200 40 42 45 47 60 67
55 12 13.5 17 19 24 26 205 41 43 46 48 61 68
60 13 14.5 18 20 26 28 210 42 44 47 49 61 69
65 14 15.5 19 21 27 29 215 42 44 47 49 62 70
70 15 16.5 20 22 28 31 220 43 45 48 50 63 71
75 16 17 21 23 29 32 225 44 46 49 51 64 72
80 17 19 22 24 30 34 230 45 47 50 52 65 73
85 18 20 23 25 31 35 235 46 48 51 53 65 74
90 19 21 24 26 33 37 240 46 48 51 53 66 75
95 20 22 25 27 34 38 245 47 49 52 54 67 75
100 21 23 26 28 35 40 250 48 50 53 55 68 76