Green Dot AUTOMATIC

POWER FACTOR

CONTROLLER

AN IDEAL SOLUTION for POWER FACTOR

CORRECTION

FIRST TIME IN INDIA

This is 3rd Generation of Development in the APFC Field.

The Market – till today was exposed to

the SECOND GENERATION units that are RELAY TYPE akin to RELAY TYPE

STABILISERS in Voltage stabiliser field. This is SERVO TYPE APFC CONTROLLER –

CONTINUOUSLY CORRECTING TYPE.

This will upgrade your concept of POWER FACTOR CORRECTION.

THE UNBALANCED TYPE APFC provides IDEAL CORRECTION to INDIVIDUAL

PHASES . This objective & advantage is not

possible from RELAY TYPE Power Factor Panels.

AT EXISTING INSTALLATIONS of RELAY

TYPE POWER FACTOR PANEL installations – a SMALL SIZED UNBALANCED TYPE UNIT will further correct POWER FACTOR of INDIVIDUAL PHASES by correcting PF of

INDIVIDUAL PHASES from AVERAGE FIGURES of SAY 0.95-0.97 to 1 & thus further saving 3-4 % on Electricity Bills.

SAY ADD 10 KVAR or 20 KVAR CONSTANTLY VARIABLE CAPACITORS in INDIVIDUAL

PHASES.

An INNOVATIVE PRODUCT

The innovative character of this APFC

controller can be best understood from

the anomaly with the Voltage stabiliser

field.

There are three STAGES of development

in the field of VOLTAGE STABILISERS /

VOLTAGE REGULATORS. The latest is a

SERVO TYPE VOLTAGE STABILISER. –

that maintains Voltage of any

establishment to + 1 % or so accuracies.

Earlier – 1st Stage was when – a Voltage

Regulator of MANUAL ROTARY TYPE was

used to adjust the voltage as is still being

done on Voltage regulators for TV etc.

There is ONE b4,6 or 8 POSITION rotary

switch that is rotated to adjust output

voltage.

In 2nd stage of this development, RELAY

TYPE STABILISERS like those used with

Air Conditioners etc. came in. There are

Steps ( 2,3,4 or 5 ) – and we call them in

the Regulating Transformers that are

Switched ON and OFF to keep output

voltage to say + 10 % or so accuracy.

In the 3rd Stage – the Servo stabilisers

came in that maintain output voltage

accuracy of + 1 % or so by using a Motor

Driven Variable Transformer .

Similarly in Power Factor Controllers, in the 1st Stage – fixed value capacitors are

added in parallel to individual motors or loads. This is a Crude method of Power

Factor Correction.

In the 2nd Stage – is the conventional Power Factor Controller that incorporates a Set of

Discrete value capacitors that are switched ON & Off to the value required through a set

of Contactors & a POWER FACTOR SENSING RELAY . This operation is similar to the

Voltage Stabilisers of Air Conditioners that contains steps & cannot switch on and off the

capacitors to any definite value required . The switching IN & OUT of the Capacitors is in

steps of say 2 KVR or so.

In the 3rd stage, similar to SERVO STABILISERS – there is no APFC that can Continuously feed

VARIABLE CAPACITANCE in the line. GREEN DOT is only ONE & ONE COMPANY in INDIA

that has perfected the technology of Cotinuously varying capacitance and have thus

introduced STEP LESS POWER FACTOR CONTROLLERS.

Further more , the existing system has some serious disadvantages. You cannot have ideal

compensation to reactive power as because of the steps only a near about compensation to Power

Factor is available. The System will always be over compensated or under compensated. The

degree of compensation deviates undesirably from the ideal values. When using six capacitors –

the deviation could be to 1/12 of the compensate value.

There exists a fear of over improvement and a name is given to this as ‘ power factor

correction better than 0.9’. With combination of increments in sizeable capacitor steps,

and abrupt full current switching, , over improvement could cause over voltages of as much

as 40 % on affected power lines and subsequent damage to motor driven equipment under

certain conditions of operation.

With every capacitive switching of capacitors, a surge or spike like , results, thus causing

a perceivable flicker which is extremely detrimental to sensitive electronic switching

loads connected to line. In fact - the capacitor switching is primary cause of trouble in

computer receiving power from lines. True in the Capacitive switching circuits, today

switching is made at ZERO VOLTAGE CROSSING, but this feature achieves a little

because in capacitors, when voltage curve is at zero , the current curve is at peak and vice

versa.

Even in the absence of Sensitive Electronic loads, the operation of contactors is a rough &

violent physical action – resulting in frequently blowing of fuses . This results in watt

losses & in this interim period, the kilowatt demand increases operational expenses until

those fuses are replaced.

If the load in power lines consists of rectifiers and particularly of rectifiers with forced

communication, which as it is known , it generates a substantial reactive power component,

and also very substantial 5th, 7th and 11th harmonics. With rectifier transformer winding

, a resonant circuit develops whose frequency closely coincides with frequency of said 5th

Harmonic, making the current seriously dangerously uncontrollable.

The capacitors used have to be furnished with discharging resistances. When there is a

power failure, a Power Disconnection or a fuse blowing and – fuses blow frequently – the

circuit has no path of discharge any where , and without discharge resistors, the

capacitors would explode at next energization, when added to existing charge. These

discharge resistances have certain cost and also consume power incessantly.

The capacitors work at all time at full rated voltage and at certain switching instances the

peak voltage is enhanced beyond the rated peak voltage of capacitors – which can destroy

or reduce the life time of these components.

Since the switching of multiple capacitors through contactors is involved, plethora of

harmonics gets introduced in the line & thereby LINE FILTERS of suitable rating have to

be installed. It is like first introducing the NOISES & HARMONICS & then putting

circuits & chokes to mitigate their evil effects.

Green Dot Electric Limited has developed a Variac Based Power Factor Panel. A Motorised

Variable Transformer ( the Motorised Dimmer Dot ) is used a source of Variable Voltage

that is applied to the required value of Capacitance rated for 440 Volts or so. The varying

voltage applied to the Fixed value capacitance-makes the Fixed value Capacitance to

Continuously Variable capacitance that is used to correct the Power Factor without steps.

There are no switching of Contactors or interruption of CAPACITIVE CIRCUITS and thus no

harmonics get introduced. The costly harmonics filters are also avoided. In case the supply

goes off & comes in – delay is provided to give time for discharge of capacitors and then to

start again at zero voltage input from the Dimmer Dot. There is further advantage in our

system that the power change is proportional to the square of applied voltage to the

capacitors whereas by comparison to Switching In, and or out Capacitors – the affect is

only to the first power of the capacitor size.

The Power Factor Sensing relay has been developed from an advanced Micro Controller that

senses the existing Power Factor & rotates the Variable Transformer forward or backward –

increasing or decreasing the output voltage of the Variable transformer, to provide required

voltage across the capacitor so that the adjusted & the required power factor is always

maintained with respect to ever varying load of the establishment. The LED Read out panel

of the Relay Box reads Input Voltage & adjusted Power Factor

THE STEP LESS POWER FACTOR CONTROLLER

Thus there is step less Varying capacitance that is made available to suit the varying

load. There is no switching surge & Power factor is maintained accurately. There are no

contactors & no complicated wiring.

3 PHASE STEP LESS POWER FACTOR CONTROLLER

STEP LESS –

THE HYBRID POWER FACTOR CONTROLLER

In this controller

both Variable

transformers &

APFC RELAY units

are built into one

to cut short the

cost.

While 3 Nos. of 1

Phase Power Factor

corrections with

three 1 Phase

Variable

transformers goes

to balance out the

differences in PF

of individual

phases, the relay

type units goes to

provide balanced

capacitor

correction.

Basically – the

unbalanced type

Power Factor

corrector with

Variable

transformers is

installed / can be

installed in addition

to EXISTING

POWER FACTOR

panels to even out

Power Factor

correction and thus

affect further

savings.