If a transformer requires 32 amps at 480 volts on the primary, what is the efficiency of this transformer if it delivers 120-volt power to a 14.6 kW load?

If a transformer requires 32 amps at 480 volts on the primary, what is the efficiency of this transformer if it delivers 120-volt power to a 14.6 kW load?

• A. 90%
• B. 92%
• C. 95%
• D. 97%

Answer: (C)

To determine the efficiency of the transformer in this scenario, it's essential to calculate both the input power and the output power. Starting with the primary side of the transformer, the input power can be calculated using the formula for power, which is P = Voltage x Current. Given that the transformer requires 32 amps at 480 volts, the input power would be: Input Power = 480 volts x 32 amps = 15,360 watts or 15.36 kW. Next, we need to calculate the output power delivered to the load. The transformer delivers 120 volts to a loading of 14.6 kW. Hence, the output power is simply the load power, which is 14.6 kW. After calculating the input and output power values, we can now compute the efficiency of the transformer. Efficiency (η) is indicated by the formula: Efficiency = (Output Power / Input Power) x 100%. Substituting in the values we obtained: Efficiency = (14.6 kW / 15.36 kW) x 100% = 0.951 or 95.1%. This efficiency value can be rounded according to common practices in engineering. A typical rounding would give us

To determine the efficiency of the transformer in this scenario, it's essential to calculate both the input power and the output power.

Starting with the primary side of the transformer, the input power can be calculated using the formula for power, which is P = Voltage x Current. Given that the transformer requires 32 amps at 480 volts, the input power would be:

Input Power = 480 volts x 32 amps = 15,360 watts or 15.36 kW.

Next, we need to calculate the output power delivered to the load. The transformer delivers 120 volts to a loading of 14.6 kW. Hence, the output power is simply the load power, which is 14.6 kW.

After calculating the input and output power values, we can now compute the efficiency of the transformer. Efficiency (η) is indicated by the formula:

Efficiency = (Output Power / Input Power) x 100%.

Substituting in the values we obtained:

Efficiency = (14.6 kW / 15.36 kW) x 100%

= 0.951 or 95.1%.

This efficiency value can be rounded according to common practices in engineering. A typical rounding would give us