Understanding 25GNDY/14.4kV Notation for Three Phase Transformer Banks

In summary, the maximum full-load primary current for a three phase 500 kVA transformer bank with a high-voltage winding of 25GndY/14.4 kV is either 11.56A or 20.07A, depending on the assumed primary voltage. The notation 25GndY/14.4kV is still unclear and there does not seem to be a definitive answer available.
  • #1
Derill03
63
0

Homework Statement


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What is the maximum full-load primary current that you could safely design for a three phase 500 kVA transformer bank to provide if it has a high-voltage winding of 25GndY/14.4 kV?

What does the notation 25GNDY/14.4kV really mean? Is it 25kV three phase and 14.4kV single phase?

Homework Equations



Full load current = VA / 1.73*Primary Voltage


3. Attempt at solution

Full load current = 500kVA / (1.73*25kV) = 11.56A *Assuming 25kV for primary voltage

Full load current = 500kVA / (1.73*14.4kV) = 20.07A *Assuming 14.4kV for primary voltage
 
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  • #2
A google search does turn up uses of the GndY notation, but I haven't been able to figure it out its meaning.

Do you have the textbook's answer to this question?
 

1. What is three phase full load current?

Three phase full load current refers to the maximum amount of electrical current that a three-phase motor can draw when operating at full load. It is typically expressed in amperes (A).

2. How is three phase full load current calculated?

Three phase full load current can be calculated by dividing the power (in watts) by the product of the square root of three, the voltage, and the power factor. The formula is: I = P / (√3 * V * PF).

3. What factors affect three phase full load current?

The primary factors that affect three phase full load current are the power supply voltage, power factor, and the type of load (inductive, capacitive, or resistive). The motor's horsepower and efficiency also play a role in determining the full load current.

4. Why is it important to know the three phase full load current?

It is important to know the three phase full load current because it helps in selecting the correct size of circuit breakers, wires, and other electrical components needed to safely and efficiently operate a three-phase motor. It is also necessary for determining the motor's power consumption and potential energy costs.

5. Can the three phase full load current change?

Yes, the three phase full load current can change depending on the operating conditions of the motor. If the load on the motor increases, the full load current will also increase. Similarly, if the efficiency of the motor changes, the full load current will also be affected. Therefore, it is important to regularly monitor and calculate the full load current to ensure proper operation of the motor.

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