If a transformer supplies power to a 240-volt, 3-phase, non-continuous 32.841 kVA load, what is the maximum rating for the secondary OCPD?

If a transformer supplies power to a 240-volt, 3-phase, non-continuous 32.841 kVA load, what is the maximum rating for the secondary OCPD?

• A. 60 Amps
• B. 70 Amps
• C. 80 Amps
• D. 90 Amps

Answer: (C)

To determine the maximum rating for the secondary Overcurrent Protective Device (OCPD), it's essential to consider the load and the characteristics of three-phase systems. In a three-phase circuit, the apparent power (in kVA) can be converted into current using the formula: \[ I = \frac{P}{\sqrt{3} \times V} \] where: - \( I \) is the current in amps, - \( P \) is the power in kVA, and - \( V \) is the voltage line-to-line in volts. For this specific example, with a load of 32.841 kVA supplied at 240 volts, the calculation can be performed as follows: 1. Convert the kVA to watts: 32.841 kVA is equal to 32,841 VA. 2. Apply the formula: \[ I = \frac{32,841}{\sqrt{3} \times 240} \] Calculating \( \sqrt{3} \) gives approximately 1.732. Now we can substitute: \[ I = \frac{32,841}{1.732 \times 240} \] \[ I = \frac{32,841}{415.68

To determine the maximum rating for the secondary Overcurrent Protective Device (OCPD), it's essential to consider the load and the characteristics of three-phase systems. In a three-phase circuit, the apparent power (in kVA) can be converted into current using the formula:

[ I = \frac{P}{\sqrt{3} \times V} ]

where:

• ( I ) is the current in amps,

• ( P ) is the power in kVA, and

• ( V ) is the voltage line-to-line in volts.

For this specific example, with a load of 32.841 kVA supplied at 240 volts, the calculation can be performed as follows:

1. Convert the kVA to watts: 32.841 kVA is equal to 32,841 VA.

2. Apply the formula:

[ I = \frac{32,841}{\sqrt{3} \times 240} ]

Calculating ( \sqrt{3} ) gives approximately 1.732. Now we can substitute:

[ I = \frac{32,841}{1.732 \times 240} ]

[ I = \frac{32,841}{415.68