141 S3 Transformers

What are transformers rated in?

• A) Watts (W)
• B) Volts (V)
• C) Volt-Amperes (VA) or kiloVolt-Amperes (kVA)
• D) Amperes (A)

How are transformers specified and rated?

• A) In kilowatts (kW)
• B) In megavolts (MV)
• C) In kiloohms (kO)
• D) In VA or kVA

Which formula is used to find the rating of a single-phase transformer in kVA?

• A) kVA = V x I
• B) kVA = (V x I) / 1000
• C) kVA = v3 x (V x I)
• D) kVA = (v3 x (V x I)) / 1000

What is the formula for finding the rating of a three-phase transformer in VA?

• A) VA = V x I
• B) VA = (V x I) / 1000
• C) VA = v3 x (V x I)
• D) VA = (v3 x (V x I)) / 1000

If a transformer has a nameplate rating of 100 kVA, what does this represent?

• A) Primary voltage
• B) Primary current
• C) Transformer efficiency
• D) Transformer rating

What is the primary voltage (High Voltage) of the transformer mentioned in the text?

• A) 11000 V
• B) 11 kV
• C) 415 V
• D) 139.1 A

What is the secondary voltage (Low Voltage) of the transformer mentioned in the text?

• A) 11000 V
• B) 11 kV
• C) 415 V
• D) 139.1 A

How is the primary current on the High Voltage (H.V.) side of the transformer measured?

• A) In kVA
• B) In amperes (A)
• C) In kilowatts (kW)
• D) In megavolts (MV)

Which formula is used to calculate the transformer rating in kVA using primary voltage and primary current?

• A) kVA = V x I
• B) kVA = (V x I) / 1000
• C) kVA = v3 x (V x I)
• D) kVA = (v3 x (V x I)) / 1000

Why might the calculated transformer rating using the three-phase formula differ slightly from the nameplate rating?

• A) Due to variations in voltage
• B) Due to variations in current
• C) Due to losses in the transformer
• D) Due to variations in frequency