Installation
As with all electrical equipment, the appropriate specifications governing electrical installation must be
followed when power factor correction equipment is installed. When removing the front nameplate to adjust
the function switch and DIP switches, always ensure that your body is not carrying any electrostatic charge.
This can be accomplished by simply touching an earthed object, such as the switchboard metal casing to
dissipate any electrical charge before removing the cover plate.
1 Check that the measurement and control voltage, supply frequency and current transformer rating comply
with the ratings given on the back of the relay.
2 Mount the relay in the switch panel (cut out size 138 x 138mm) and retain the relay in position using the
ratchet plastic clips included with the relay.
3 Connect in accordance with the wiring diagram.
Pay special attention to the cross section size of the
CT connections. We recommend 2.5 sq.mm copper conductor for runs up to 10 mtrs.
The CX relay will
constantly monitor the supply voltage and if this falls below 70% of nominal all capacitor contactors will be
automatically switched out. Note that the control voltage to the supply voltage to the contactor coils must be
taken from one of the phases used for the supply voltage to the relay (L2-L3). The spring terminal can be
pushed open by hand – or with a 2.5mm blade screwdriver. The steel rear cover of the relay must be
earthed, at the earth tag.
4 CT outputs of 1A or 5A Class 1 are fed into the two orange terminals marked K-L. When using the CXM
multi-meter version the max. CT ratio is 20000/5 or 4000/1. Note that the CX and CXM relays are sensitive
down to a current of 0.010 A (10 mA) reactive. The CT input ratio of 1A or 5A is self selecting according
to the max CT current measured. The CX relay is therefore sensitive enough to switch a 25 kvar capacitor
step at 415V utilising a 10,000/5 CT, or 5 kvar step using a 10000/1 CT ratio, provided the max total
current from the CT does not exceed 1 amp.
Function Switch Control Positions
The function control switch (H3) is located behind the removable front plastic nameplate. For the CX relay there
are two push buttons ( + & - ) located either side of the function switch. For the CXM (multi-meter version)
the + & - keys are on the front of the relay. They also allow you to roll through the different measured values of
U-I-P-Q-S-F-COSPHI.
If option "L" (fan control) is fitted there will be 2 additional DIP switches (S1/S2) located behind the name plate
to select the 4 temperature alarm levels of 30-35-40-45 deg.C.
Factory setting of the function switch is 0 off - see below.
.
Multifunction Switch (H3) Rotate the switch to the position required with a small screwdriver
0 All steps switched off. If the relay is energised, when the function switch is turned to this position, the steps
will be switched off after a time delay of 20 secs. If the + - keys are used in this position, you can select the
threshold level at which you want the relay to show a capacitor step is defective. You can set this value
between 10…..60% of the first recorded kvar value of each step. The factory setting is 50%, so the display
will alternate between "50" and "0".
1
p.f. target set,
selectable in the range of 0.70 lag …1…0.90 lead; Lag is prefixed i Lead = c in display.
Factory setting = 1.0
2
Switching time delay in secs,
selectable from 5 ... 1200 secs. Pushing or – for longer than 2 sec.
enables rapid selection.
Factory setting: 60 secs.
3
Fully automatic control of power factor correction bank.
LED Display will indicate the system power
factor with either I for inductive or C for capacitive load (updated each 3 sec.) A flashing dot in display above
the signs or – indicates, that the regulator is selecting a suitable capacitor, if available, to meet the
reactive load demand. This adjustment is made every 3 secs.
The CXM relay will indicate COSo - Power factor, U-volts, I –Amps, P-kW, S – kVA , Q – kvar, F - Hz
4
Manual operation
"H" will show in the display to indicate the relay is in "hand" control. Steps are switched in/out using the +/ -
buttons. The selected time delay per step (pos. 2) will be followed. This is useful when commissioning a
bank where there is low or little load. Using the manual control steps can be switched in so as to create a
leading power factor. Then put the function switch back to pos.3, for auto control and the relay should adjust
automatically to the target pf. selected in Pos 1.
2
