Recent content by that.kid

  1. T

    I'm currently stuck on a transformer question and require a little clarification

    Yes, I have referred it back to the primary and drawn an equivalent circuit. Referring it to the primary I got R(E)=1123.6 and X(Z)=674.16. What equation did you use to calculate the copper/core losses? I've tried P=I^R and P(open circuit)=P(input)*I(open circuit)*power factor and P(short...
  2. T

    I'm currently stuck on a transformer question and require a little clarification

    I know that if I do (50 * 0.8)/(50 * 0.8 +(2+1)) I get an efficiency of about 93%, where the 50 is the 50 KVA input voltage, the 0.8 is the power factor, the 2 comes from the 2KW input on the open circuit test, and the 1 comes from the 1KW input on the short circuit test. I think I'm just...
  3. T

    I'm currently stuck on a transformer question and require a little clarification

    From the open circuit test, I got Rc = 7950 ohm, and Xm = 10600 ohm From the short circuit test, I got z = 1.6 angle 36.86 degrees using the formula z(s/c) = (short circuit voltage/short circuit current) angle theta I found the angle (theta) from PF = cos theta I'm not sure what I've done...
  4. T

    I'm currently stuck on a transformer question and require a little clarification

    I think it's wrong because transformers should usually have an efficiency of ~90% and above. To be getting such an inefficient transformer with those values just doesn't seem right. Can anybody please confirm?
  5. T

    Deflection in a simply supported beam with a rigid arm underneath

    Have you drawn a free body diagram of the beam yet? That would be my starting point. Firstly, resolve the UDL into a point force, acting equidistant between the points where the UDL is applied. force on the arm will create a moment where the arm is attached to the rigid beam, which is...
  6. T

    I'm currently stuck on a transformer question and require a little clarification

    Homework Statement A 50 kVA 6360 V/240 V, 50 Hz, transformer is tested on open circuit and short circuit to obtain its efficiency. The results of the tests are as follows: Open Circuit: Primary Voltage 6360 V, Primary current 1.0 A, Input power 2 kW. Short Circuit: Voltage across primary...
Back
Top