Transformer Principles and Calculations

The video tutorial explains the basic principles of transformers, including different types such as single-phase and three-phase transformers. It covers the schematic of a single-phase transformer, emphasizing the power rating and efficiency. The tutorial discusses the concept of turns ratio and its effect on voltage, as well as how to calculate current and power using given values. The importance of understanding transformer efficiency and power losses is highlighted, along with practical examples of calculations.

What is a common feature of all transformers, regardless of their size or application?

• They all require three-phase power.

• They all operate on the same basic principles.

• They all have built-in cooling fans.

• They all use direct current.

What does the power rating of a transformer in volt-amps indicate?

• The number of turns in the coil.

• The efficiency of the transformer.

• The total power it can transfer.

• The maximum voltage it can handle.

How is the voltage on the secondary coil related to the primary coil in terms of turns ratio?

• It is equal to the number of turns on the primary coil.

• It is inversely proportional to the number of turns on the primary coil.

• It is directly proportional to the number of turns on the primary coil.

• It is one-tenth of the voltage on the primary coil if the turns ratio is 10:1.

What happens to the current when the voltage is reduced in a transformer?

• The current increases.

• The current becomes zero.

• The current remains the same.

• The current decreases.

How can you calculate the current if you know the power in volt-amps and the voltage?

• Multiply the power by the voltage.

• Divide the power by the voltage.

• Add the power and voltage.

• Subtract the voltage from the power.

What is the relationship between voltage and current in a transformer?

• They are unrelated.

• They are equal.

• They are inversely proportional.

• They are directly proportional.

If a transformer has a primary voltage of 120 volts and a secondary voltage of 12 volts, what is the turns ratio?

• 10:1

• 1:1

• 1:10

• 12:120

What is the significance of the turns ratio in a transformer?

• It is directly proportional to the voltage transformation.

• It is inversely proportional to the voltage transformation.

• It indicates the size of the transformer.

• It determines the efficiency of the transformer.

What is the primary purpose of using a transformer?

• To store electrical energy.

• To generate electricity.

• To change the voltage level.

• To increase the current.

Which of the following is true about power in a transformer?

• Power is lost during transformation.

• Power in equals power out for basic calculations.

• Power is always decreased in the primary coil.

• Power is always increased in the secondary coil.