The missing values.
Explanation of Solution
The given values are shown in below table:
Primary (P) | Secondary (S) | Load (L) | |||
7200 | 240 | ||||
Ratio |
Refer to the circuit shown in Figure 8-30.
The primary windings of three single phase transformer are connected in wye connection. In wye connection, the line voltage is equal to
The secondary windings of three single phase transformer are connected in delta connection. In delta connection, the line voltage is equal to phase voltage.
Calculate the turns ratio of primary and secondary winding.
Thus, the turns ratio
Since, the secondary winding (S) is directly connected to the load (L). Thus, the line voltage of secondary winding and load are equal.
Here, the load uses wye connection. In wye connection, the line voltage is equal to
Calculate the phase current of the load
In wye connection, the phase current
Since, the secondary winding (S) is directly connected to the load (L). Thus, the line current of secondary winding and load are equal.
Here, the secondary winding uses delta connection. In delta connection, the line current is equal to
Calculate the phase current in primary winding
Since, the primary winding uses wye connection. In wye connection, the line current is equal to phase current.
Thus, the all missing values are calculated and shown in below table:
Primary (P) | Secondary (S) | Load (L) | |||
4156.92 | 440 | 138.56 | |||
1.15 | 20 | 34.64 | |||
7200 | 240 | 240 | |||
1.15 | 34.64 | 34.64 | |||
Ratio | 17.32:1 |
Want to see more full solutions like this?
Chapter 8 Solutions
Electrical Transformers and Rotating Machines
- Refer to the transformer shown in Figure 5-13 to answer the following questions. What is the turns ratio of the winding between points B and E as compared to the winding between points D and E? Figure 5-13 Autotransformer practice problems.arrow_forwardRefer to the transformer connection shown in Figure 8-31 to fill in the following values. Figure 8-31 Practice problems circuit 2arrow_forwardRefer to the transformer shown in Figure 5-13 to answer the following questions. The transformer shown in Figure 5-13 is supplying 325 volt amperes to a load. The primary voltage is 240 volts. What is the primary current? Figure 5-13 Autotransformer practice problems.arrow_forward
- Assume that a line voltage of 2400 volts is connected to the primary of the three-phase transformer and the line voltage of the secondary is 240 volts. What is the turns ratio of the transformer?arrow_forwardA transformer has a primary voltage of 240 volts and a secondary voltage of 48 volts. What is the turns ratio of this transformer?arrow_forwardThe primary leads of a transformer are labeled 1 and 2. The secondary leads are labeled 3 and 4. If polarity dots are placed beside leads 1 and 4, which secondary lead would be connected to terminal 2 to make the connection additive?arrow_forward
- A load impedance of 52 Ω is connected to the secondary winding of the transformer in question 3. How much current will flow in the secondary?arrow_forwardIs the transformer in question 1 a step-up or step-down transformer?arrow_forwardAn AC power source is connected across 325 turns of an autotransformer, and the load is connected across 260 turns. What is the turns ratio of this transformer?arrow_forward
- Refer to the schematic in Figure 7-10. Assume that when the START button is pressed, the control transformer fuse blows. What is the most likely cause of this trouble? Figure 7-10 Numbers are placed beside all components.arrow_forwardA 480-volt three-phase load is rated at 34.5 kVA. It is to be supplied with variable three-phase voltage. Because the load is continuous, the transformers ratings are to be increased by 1.25% of the rated load. Three variable autotransformers are used to supply this load. Refer to Table 4-2 and determine the standard size of each transformer that should be used to make this connection.arrow_forwardIf the secondary of the transformer in question 5 supplies a current of 9.6 amperes to a load, what is the primary current? (Disregard excitation current.)arrow_forward
- Electrical Transformers and Rotating MachinesMechanical EngineeringISBN:9781305494817Author:Stephen L. HermanPublisher:Cengage LearningUnderstanding Motor ControlsMechanical EngineeringISBN:9781337798686Author:Stephen L. HermanPublisher:Delmar Cengage Learning