INSTALLATION OF APFC PANEL

1

HOW TO INSTALL THE PANEL ?

  1. Unpack the panel.

  2. Put it on a proper foundation with Nuts and Bolts.

  3. Remove the power contactor cover and the packing kept between contacts and fix the contactor cover.

  4. Connect power cables to the mains and the respective capacitor banks through the bottom tray. (Make suitable cut-outs in the bottom tray for cables entries).

  5. Connect the CT's in the mains connections to the terminal block provided at the bottom, taking care to ensure the correct polarity.

  6. Check loosening of wires, cables, etc. Tighten loose contacts, if any.

  7. Put Auto/Manual/Off Switch in off position.

2

HOW TO SWITCH ON THE PANEL ?

  1. Switch ON mains to panel and switch On the Isolator.

  2. Check the mains indicator lamps and the voltage on the panel meter, for all the R, Y, B Positions of the selector switch.

  3. It stage (2-b) is not OK, check busbar voltage, metering fuses and metering wires. Correct where required.

  4. Check P.F. meter reading (without capacitors, it generally shows a lagging PF.)

  5. If stage (2-d) is not correct, then reverse the polarity of one of the CT's connected to the PF meter.

3

HOW TO CHECK THE OPERATION OF THE PANEL ?

  1. Put the Auto/Manual/Off switch in `Manual' position. Make sure that some mains load is present and is adequate for testing and relay setting purposes. It is roughly 1.3 A per KVAR for each step of capacitor control. Without this, do not switch ON the capacitors.

  2. Push the first `ON' push button for an instant and wait. The first bank will be on. If not, make another effort after about a minute or so.

  3. If stage 3-b is not OK, check pneumatic timer operation & connections.

  4. Measure the time interval between the button pushing instant & when the respective contactor becomes "ON" (It should be around one minute.)

  5. If necessary, re-adjust the pneumatic timer timing for about one minute delay.

  6. Check the panel ammeter reading and read the capacitor bank current for all the 3 phases. Each capacitor or bank current should be 1.3A per KVAR on each stage/step of the P.F. relay.

  7. Switch on enough capacitors so that the desired P.F. is obtained. Switch them off as necessary.

4

HOW TO OPERATE AUTOMATICATICALLY ?

  1. Put off the Auto/Manual Off Switch to the Off position for a minute and then change over to Auto Position.

  2. Make sure that the relay supply is on. The `Power' Led on the relay will light up.

  3. If stage (4-b) is not OK, check voltage across Relay `R', `B' terminals.

    4. (It should be the line voltage). If it is not so, check these wires.

  4. Remove the front cover of the relay and set the three presets with a screw driver as follows :-

  • `Min Lag' preset at the extreme anti-clockwise position

  • `Max Lag' preset at the extreme clockwise position

  • `Amps' preset at the extreme anti-clockwise position.

  1. As per positions mentioned in (d), the `control' LED should be off, for a lagging P.F. (which is common).

  2. If the control LED does not go off as per (e), reverse the respective CT's Connections to the P.F. relay.

  3. Read the P.F. If it is more lagging than required (required value generally 0.85 lag), turn the `Max. Lag' preset slowly anti-clockwise till `control' LED becomes `on' and wait for two minutes.

  4. First capacitor bank `ON' LED will be on. Simultaneously first contactor will be on. If not, check neutral connections of relay and contactor coil connections. If loose, tighten or correct.

  5. You can observe the improvement in P.F.

  6. If `Control' LED is off and P.F. is still less again, repeat the procedure as per (f-9).

  7. The relay will repeat the above procedure and achieve the desired P.F. by switching on capacitor banks automatically.

  8. Please remember that for the P.F. lying within the set range condition, `control' LED should be off.

  9. Similarly to set `min, lag' preset (generally min, lagging P.F. is unity) when the P.F. is leading, slowly turn it in the clockwise direction, so that `control' LED will be on and it will switch off the capacitor banks one by one with a certain time of interval.

  10. Repeat the procedure in (m) till the P.F. comes within the range desired.

  11. To set the `Amps' preset, adjust the mains current approximately to the current of one capacitor bank, i.e. to a value equal to capacitor stage/step KVr x 1.3A.

  12. See the P.F. If it is out of the selected range, the `control' LED will be on at its minimum clockwise position. This means that at light load conditions below the value set by `Amperes' present, the relay will shut off the capacitors completely and prevent undue hunting on light loads.

  13. If the selected P.F. band- width of relay operation is correct, there should not be hunting of the capacitor banks; if not so, increase the max. lag limit slightly.

  14. Suppose that the load requires on the average 75 KVAR of Capacitors and the P.F. relay keeps the contacts hunting around one step even after widening the range between `min. & max' presets.

Then either remove one or two basic capacitor units from the next stage or add one or two basic capacitor units to the lower hunted stage. Alternatively, one or two basic units of capacitors can be added outside the P.F. control to the mains directly. This will prevent hunting.

 

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