Delta Transformer

The figure given for this calculation is 58%. This percentage assumes a closed delta bank containing 3 transformers. If three 167 kVA transformers were connected to form a closed delta connection, the total output would be (3 x 167 = 500 kVA). If one of these transformers were removed and the transformer bank operated as an open delta connection, the output power would be reduced to 58% of its original capacity of 500 kVA. The output capacity of the open delta bank is (500 kVA x .58% = 290 kVA). Another figure you will see is 87%. This is 87% of the capacity of the two remaining transformers or 167 x 2 x .87 or 290 kva.

thanks for your prompt response Wareagle. I am an insurance adjuster taking a course to learn more about transformers and AC motors etc but all of this math hurts my head and does not interest me at all as I will never be required to use it. I'm wondering if you could help me out with one more question: A single phase 1 hp motor consumes 9A at supply voltage of 123V at 60Hz at a power factor of 78% while driving a fan. What is the power taken by the motor?

quote " A single phase 1 hp motor consumes 9A at supply voltage of 123V at 60Hz at a power factor of 78% while driving a fan. What is the power taken by the motor?"

1 Hp is = 746 watts for the perfect motor. So far we can not build one yet.

So 123 volts x 9 amps x 0.78 pf = 863 watts. This will include the inefficiency of the motor.

what are you planning to do with this type of information?

thanks again. I'm just trying to complete a class assignment so all of this info is hypathetical. That is actually the answer I calculated as well so at least it appears I am doing something right!!

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The idea of a class assignment is you do it yourself. That way you learn.