*This summary of the video was created by an AI. It might contain some inaccuracies.*

## 00:00:00 – 00:25:54

The video focuses on teaching the calculation of electrical parameters in star and delta-connected loads using a worksheet. Key points include the computation of phase voltage, phase current, and line current for different configurations using Ohm’s law and other electrical principles. The calculations involve a 415-volt supply for star-connected loads with resistances of 25 ohms, yielding a phase current of 9.58 amperes and a line current also of 9.58 amperes. For delta-connected loads, the phase voltage equals the line voltage (415 volts), resulting in a higher phase current of 16.6 amperes and a line current of 28.75 amperes.

Additionally, the video discusses scenarios with a 400-volt supply and 50-ohm resistors, showing that in a star configuration, the phase current is 4.618 amperes and in delta, the phase current is 8 amperes with a line current of 13.86 amperes. Similarly, for a 440-volt supply with 220-ohm resistors, the star configuration results in a phase current of 1.15 amperes, whereas in delta, the phase current is 2 amperes with a line current of 3.46 amperes.

The themes emphasize understanding the impacts of different connections on current and voltages, the use of proper formulas, and verifying calculations. Important terms include phase voltage, phase current, line current, Ohm’s law, star connection, and delta connection. The video concludes by reinforcing the importance of these calculations for practical electrical engineering applications.

### 00:00:00

In this part of the video, the instructor begins by welcoming viewers to an electrical principles training session, designed to be used alongside a downloadable worksheet. The video then addresses question one from the worksheet, which involves calculating the phase voltage, line current, and phase current for three identical resistive loads of 25 ohms connected in a star configuration to a 415-volt supply. The instructor emphasizes the importance of sketching the problem and listing known values: the line voltage (415 volts) and the resistance (25 ohms). Additionally, the instructor advises viewing a previous video to better understand the concepts of line voltage and phase voltage before proceeding with the calculations.

### 00:03:00

In this part of the video, the speaker explains how to calculate the phase voltage and phase current in a star-connected electrical load. They start with the formula for phase voltage (line voltage divided by the square root of three) and perform the calculation using a line voltage of 415 volts, resulting in a phase voltage of 239.6 volts. Next, they use Ohm’s law (V = IR) to determine the phase current by dividing the calculated phase voltage (239.6 volts) by the resistance (25 ohms), finding a phase current of 9.58 amperes. Finally, the speaker notes the importance of understanding the relationship between line current and phase current in a star-connected load, as discussed in previous videos.

### 00:06:00

In this part of the video, the presenter explains the calculation of currents and voltages in star and delta connected loads. Specifically, they discuss how in a star-connected load, the line current (I_L) is equal to the phase current (I_P), which simplifies the calculation to find the current as 9.58 amperes. They then move on to a worksheet question involving a delta-connected load with resistors of 25 ohms connected to a 415-volt supply. The objective is to calculate the phase voltage (V_P), line current, and phase current. They start by identifying known values: the line voltage (V_L) is 415 volts, and the resistors are 25 ohms each. Using the principle that in a delta connection V_P equals V_L, they determine the phase voltage to be 415 volts.

### 00:09:00

In this part of the video, the speaker discusses calculating the phase current using Ohm’s law, where the phase voltage (415 volts) is divided by the resistance (25 ohms), resulting in a phase current of 16.6 amperes. The speaker then explains that the line current, which is higher due to the nature of three-phase systems, can be calculated by multiplying the phase current by the square root of three. This results in a line current of 28.75 amperes. The speaker goes on to verify the calculations and fills in the appropriate values for the phase voltage, phase current, and line current, emphasizing the significant increase in current when resistors are connected in Delta rather than in star configuration.

### 00:12:00

In this segment, the video explains how connecting the same load in star and delta configurations affects the current in the system, specifically, that the current in a delta connection is three times higher than in a star connection. The speaker then addresses a specific problem from a worksheet involving three identical 50-ohm resistive loads connected in a star configuration to a 400-volt supply. The given values are a resistance of 50 ohms and a line voltage of 400 volts. To find the phase voltage, they divide the line voltage by the square root of three, resulting in approximately 230.9 volts. They further calculate the phase current using Ohm’s law by dividing the phase voltage by the resistance, yielding a phase current of approximately 4.618 amperes.

### 00:15:00

In this segment of the video, the speaker is explaining how to calculate various electrical parameters for different load configurations. Initially, the current through a star-connected load is discussed, with the line current being equal to the phase current at 4.618 amps. The speaker then moves on to a delta-connected load with a 50-ohm resistor connected to a 400-volt supply. It is emphasized that in a delta connection, the phase voltage equals the line voltage, which is 400 volts. Using Ohm’s law, the phase current is calculated to be 8 amps (400V/50Ω). Next, the calculation of the line current is hinted at, suggesting familiarity with results from a previous example.

### 00:18:00

In this part of the video, the speaker explains the relationship between phase current and line current in a three-phase electrical system. The line current is calculated by multiplying the phase current (given as 8 A) by the square root of 3, resulting in approximately 13.86 A. The speaker then addresses a problem involving three identical resistive loads of 220 ohms connected in a star configuration to a 440-volt supply. To solve this, the phase voltage is determined by dividing the line voltage (440 V) by the square root of 3, yielding approximately 254 volts. This phase voltage is essential for calculating the phase current, as the current through the load depends on the voltage across it.

### 00:21:00

In this part of the video, the speaker explains how to calculate the phase current using Ohm’s Law by dividing the phase voltage (254V) by the resistance (220 ohms), resulting in a phase current of 1.15 amperes. This phase current is then used to determine the line current in a star-connected system, which is also 1.15 amperes, as line and phase currents are the same in such a system.

The speaker then transitions to question 6, where the same load (220 ohms) is now connected in a Delta configuration to a 440V supply. They note the importance of recording known values and structuring calculations neatly for clarity. To start, they calculate the phase voltage in a Delta system, which equals the line voltage of 440V. Next, they prepare to calculate the phase current again using Ohm’s Law, emphasizing that the phase current depends on the phase voltage applied to the load.

### 00:24:00

In this part of the video, the calculation for the phase current in a Delta connected system is performed, resulting in 2 amperes. Following this, the line current is determined using the relationship between phase current and line current, specifically the formula ( I_L = I_P times sqrt{3} ). By multiplying the phase current (2 amperes) by the square root of 3, the line current is calculated to be approximately 3.46 amperes. This completes the answers needed for the given question, providing values for the phase voltage, phase current, and line current. The video then concludes with a thank you message to the viewers.