The following information is given in connection with tests performed on a 50 KVA 4,600/230 Volt 60 Hz Transformer : Short Circuit Test. Esc= 150 Volts Psc= 615 Watts Isc= 10.87 A 1. %  Resistance 2. % Impedance

10 A three-phase transformer is given. The number of turns of the high voltage winding is N1=850 and the number of turns of the low voltage winding is N2=34. The high voltage winding is energized with V1= 10 kV rms line-to-line and V2= 400 V rms line-to-line has been taken from the low voltage winding. What is the connection of the low voltage winding if the high voltage winding is Y-connected? Εισαγάγετε την απάντησή σας

Q2 During routine tests of a three phase transformer, measurements of DC resistance between winding terminals is noted down. What kind of information can be obtained from the values so noted?

Two transformers A and B have the following data Transformer A: 6600/440 V, (250 KVA ) requires ( 6%) of rated voltage to circulate (90%) of full load current at power factor (0.25) when the low voltage winding is short circuited and the no load loss is equal to (2500 W). Transformer B: 6600/420 V, (600 KVA) requires (9%) of rated voltage to circulate (80%) of full load current at power factor (0.16) when low voltage winding is short circuited and no load loss is equal to (4500 W). Calculate the followings: If both transformers are connected in parallel to supply a load (1.2 + j 2.3) ohm, find the output power of each transformer.

When 2200 volts, 60 Hz is impressed on a certain transformer, the core loss is 240 Watts. When the frequency of the impressed voltage is changed to 25 Hz and the voltage is reduced to maintain the same flux density as before, the core loss falls to 75 Watts. Neglect impedance drop. What is the hysteresis loss at 60 Hz?

Two transformers A and B have the following data Transformer A: 6600/440 V, (250 KVA ) requires ( 6%) of rated voltage to circulate (90%) of full load current at power factor (0.25) when the low voltage winding is short circuited and the no load loss is equal to (2500 W). Transformer B: 6600/420 V, (600 KVA) requires (9%) of rated voltage to circulate (80%) of full load current at power factor (0.16) when low voltage winding is short circuited and no load loss is equal to (4500 W). Calculate the followings: The terminal voltage when transformer A is supplying half load at power factor (0.6) lagging and transformer B is supplying (85%) of full load at power factor (0.85) leading.

Example 2-2. The equivalent circuit impedances of a 20-kVA, 8000/240-V, 60-Hz transformer are to be determined. The open-circuit test and the short-circuit test were performed on the primary side of the transformer, and the following data were taken: Open-circuit test (on primary) Short-circuit test (on primary) Voc = 8000 V Vsc = 489 V loc = 0.214 A Isc = 2.5 A Voc = 400 W Ps = 240 W

Answer only please The resistance of a transformer winding is 0.25 ohm at 25oC. When operating at full load, the temperature of the winding is 75oC. The temperature coefficient of resistance for copper at 0oC  is 0.00427 per oC. What is the winding resistance at full load? a. 0.512 ohm b. 0.315 ohm c. 0.298  ohm d. 0.271 ohm

Q Two transformers A and B have the following data Transformer A: 6600/440 V, (250 KVA ) requires ( 6%) of rated voltage to circulate (90%) of full load current at power factor (0.25) when the low voltage winding is short circuited and the no load loss is equal to (2500 W). Transformer B: 6600/420 V, (600 KVA) requires (9%) of rated voltage to circulate (80%) of full load current at power factor (0.16) when low voltage winding is short circuited and no load loss is equal to (4500 W). Calculate the followings: The maximum efficiency of each transformer at power factor (0.75) lagging.

In the circuit in Figure 2, the capacitor connected to the a-b terminals of the transformer anda circuit consisting of resistance is defined as a load circuit. a)Find the average power spent by the load circuit? b) How much of the average power calculated in a) by the resistance in the load circuit and how muchspent by the capacitor? Comment on the results obtained?