**Measurement of Load Power using Two Wattmeters**

To determine the power consumed by a balanced three-phase load, two wattmeters are typically used. These wattmeters are connected in a three-phase system to measure both the active and reactive power components of the load.

**Given Information:**
- Source Voltage (V) = 400 V
- Line Current (I) = 5 A
- Power Factor Angle (Φ) = 30 degrees lagging

To measure the power consumed by the load, two wattmeters are connected in a three-phase system. The wattmeters are connected in the following manner:

1. **Wattmeter 1 (W1):**
- Connected in the R phase (Red) of the three-phase system.
- Measures the power consumed by the R phase of the load.

2. **Wattmeter 2 (W2):**
- Connected in the Y phase (Yellow) of the three-phase system.
- Measures the power consumed by the Y phase of the load.

The readings of the two wattmeters can be used to calculate the total power consumed by the load.

**Calculation of Active Power (P) and Reactive Power (Q):**

The active power (P) and reactive power (Q) can be calculated using the following formulas:

- Active Power (P) = W1 + W2
- Reactive Power (Q) = √(W1² + W2² - 2W1W2cos(θ))

Where:
- W1 and W2 are the readings of wattmeter 1 and wattmeter 2 respectively.
- θ is the phase angle between the two wattmeters, which can be calculated as θ = Φ - 30 degrees.

**Explanation of Power Factor Angle:**

The power factor angle (Φ) indicates the phase difference between the voltage and current waveforms in an AC circuit. A positive power factor angle indicates a lagging power factor, while a negative angle indicates a leading power factor.

In this case, the power factor angle is given as 30 degrees lagging. This means that the current waveforms lag behind the voltage waveforms by 30 degrees.

**Conclusion:**

To measure the power consumed by a balanced three-phase load, two wattmeters are used. The readings of these wattmeters can be used to calculate the active and reactive power components of the load. In this particular scenario, a 400 V three-phase 50 Hz balanced source is supplying power to a load with a line current of 5 A and a power factor angle of 30 degrees lagging. The readings of the two wattmeters can be used to calculate the active and reactive power components of the load.

W2=2000 w1=10000 how