A 5 KVA transformer rated for a primary voltage of 480 volts can deliver a maximum output of how many kVA if the applied voltage is 440 volts?

A 5 KVA transformer rated for a primary voltage of 480 volts can deliver a maximum output of how many kVA if the applied voltage is 440 volts?

• A. 5.0 kVA
• B. 4.5 kVA
• C. 4.58 kVA
• D. 3.5 kVA

Answer: (C)

To determine the maximum output of a 5 kVA transformer when supplied with a primary voltage lower than its rated voltage, you need to understand how voltage affects the apparent power (kVA) rating of the transformer. The kVA rating is based on the primary voltage and the capacity of the transformer. When the transformer is supplied with a primary voltage of 440 volts instead of its rated 480 volts, the output capacity needs to be adjusted proportionally. The formula to find the new kVA output based on the change in voltage is: \[ \text{New kVA} = \text{Rated kVA} \times \left( \frac{\text{Applied Voltage}}{\text{Rated Voltage}} \right) \] Substituting the values into this formula: \[ \text{New kVA} = 5 \text{ kVA} \times \left( \frac{440 \text{ volts}}{480 \text{ volts}} \right) \] Calculating the fraction: \[ \frac{440}{480} = 0.91667 \] Now, multiply: \[ \text{New kVA} = 5 \times 0.91667 \approx

To determine the maximum output of a 5 kVA transformer when supplied with a primary voltage lower than its rated voltage, you need to understand how voltage affects the apparent power (kVA) rating of the transformer. The kVA rating is based on the primary voltage and the capacity of the transformer.

When the transformer is supplied with a primary voltage of 440 volts instead of its rated 480 volts, the output capacity needs to be adjusted proportionally. The formula to find the new kVA output based on the change in voltage is:

[

\text{New kVA} = \text{Rated kVA} \times \left( \frac{\text{Applied Voltage}}{\text{Rated Voltage}} \right)

]

Substituting the values into this formula:

[

\text{New kVA} = 5 \text{ kVA} \times \left( \frac{440 \text{ volts}}{480 \text{ volts}} \right)

]

Calculating the fraction:

[

\frac{440}{480} = 0.91667

]

Now, multiply:

[

\text{New kVA} = 5 \times 0.91667 \approx