Hi, in this article, we are going to see both Single Phase and Three Phase Digital Power Factor Meter Connection Diagrams. A power factor meter is a measuring instrument used to measure the power factor of an electrical system. The power factor is the ratio of real power (measured in watts) to apparent power (measured in volt-amperes), and it indicates how effectively the electrical power is being used. A power factor close to 1 indicates that electrical power is used efficiently, while a power factor significantly less than 1 indicates poor efficiency.

## Single Phase Power Factor Meter Connection Diagram

Here, you can see the connection diagram of a single-phase power factor meter.

### Connection Description

Direct Connection (It is used when the load current is less than 5A)
1. The power supply is to be measured is directly connected to the VP and VN input terminals for voltage input.
2. The S1 and S2 terminals of the meters are connected in series with the power source and load for current input.
3. A 230V single-phase AC supply is connected to the 230V input terminals to power up the meter to display readings.

Via CT Connection (It is used when the load current is more than 5A)

1. The power supply is to be measured is directly connected to the VP and VN input terminals for voltage input.
2. The S1 and S2 terminals of the meters are connected to the CT that is placed with the phase conductor and measures the flow of load current.
3. A 230V single-phase AC supply is connected to the 230V input terminals to power up the meter to display readings.

## Three-Phase Power Factor Meter Connection Diagram

Here, in the below figure, you can see the connection diagram of a three-phase power factor meter.

### Connection Description

1. Here, each of the three phases contains Current Transformers. The CTs are connected to their CT input Terminals of the meter e.g. the CT placed with the R phase connected to the RM and RL CT input terminals of the meter. Similarly, another two CTs are connected.
2. The three-phase power supply with neutral is directly connected to the three-phase input terminals of the meter for voltage input.
3. A single-phase 230V power supply is connected to the 230V AC input terminals of the meter to power up the meter to show the readings.

## Working Principle

A digital power factor meter measures the power factor by analyzing the relationship between the voltage and current waveforms in an electrical system. First of all, the meter measures the voltage across the load and the current flowing through the load. Then the sensed analog signals (voltage and current) are converted into digital signals using Analog-to-Digital Converters (ADCs). This digital data is then processed by the meter’s microcontroller or digital signal processor (DSP). Basically, the meter samples the voltage and current waveforms at a high rate to accurately capture their shapes and phase relationship.

The meter calculates real power by multiplying the instantaneous voltage and current values and averaging them over a complete cycle. This gives the real power in watts (W).
The meter calculates apparent power by multiplying the root mean square (RMS) values of voltage and current. This gives the apparent power in volt-amperes (VA).

The meter also calculates the phase difference between the voltage and current waveforms. This phase difference (φ) is crucial for determining the power factor.

After determining Real Power, Apparent Power, and Phase difference or phase angle finally, it calculates the power factor.