Question

При включении электродвигателя мощностью 600 Вт в сеть переменного тока амплитудные значения силы тока и напряжения принимают следующие значения I=6 А и U= 400В. Определите сдвиг фаз между током и напряжением

Answer 1

Мощность P=U*I*cos(φ), где φ - угол сдвига фаз между напряжением и током. Отсюда cos(φ)=P/(U*I)=600/(6*400)=0,25 и φ=arccos(0,25)≈75,5°. Ответ: φ≈75,5°. 

Answer 2

Calculation of Phase Shift between Current and Voltage

To determine the phase shift between the current and voltage in an AC circuit, we need to use the power factor formula. The power factor (PF) is the cosine of the angle between the current and voltage waveforms. It is calculated as the ratio of the real power (P) to the apparent power (S).

The formula for power factor is:

PF = P / S

Where: - P is the real power (in watts) - S is the apparent power (in volt-amperes)

In this case, we are given the power of the motor (600 W), the current (6 A), and the voltage (400 V). We can calculate the apparent power using the formula:

S = U * I

Where: - U is the voltage (in volts) - I is the current (in amperes)

Let's calculate the apparent power first:

S = 400 V * 6 A = 2400 VA

Now, we can calculate the power factor:

PF = P / S = 600 W / 2400 VA = 0.25

The power factor is 0.25, which means the angle between the current and voltage waveforms is 75 degrees.

Therefore, the phase shift between the current and voltage in this circuit is 75 degrees.

Please note that the above calculation assumes a purely resistive load. If the motor has inductive or capacitive components, the power factor may be different, and the phase shift calculation may require additional information about the motor's characteristics.