NEIEP Mechanics Practice Exam

What is the power available from a 68KVA transformer connected in open delta configuration?

1. 34.72KVA

2. 39.44KVA

3. 45KVA

4. 50KVA

The correct answer is: 39.44KVA

In an open delta configuration, which consists of two transformers instead of the standard three, the total power available is 57.7% of the power that would be available if all three transformers were used. This is an important characteristic of the open delta because it allows for reduced power handling capacity while still being able to provide some level of service. When we apply this percentage to the power rating of a transformer, in this case, a 68 KVA transformer, we calculate the available power in an open delta. Specifically, we take 68 KVA and multiply it by 0.577 (which is the same as 57.7%). This results in approximately 39.44 KVA. Therefore, the correct answer reflects the amount of power effectively available from a 68KVA transformer configured in open delta, which is 39.44 KVA. This understanding is crucial for professionals working with transformer configurations to ensure proper power management in electrical systems.