Concept explainers
If Vab = 400 V in a balanced Y-connected three-phase generator, find the phase voltages, assuming the phase sequence is:
- (a) abc
- (b) acb
(a)
Find the phase voltages for the abc sequence.
Answer to Problem 1P
For the abc sequence,
The phase voltage
The phase voltage
The phase voltage
Explanation of Solution
Given data:
For a balanced Y-connected three phase generator,
The line to line voltage (line voltage)
The phase sequence is abc.
Formula used:
The line voltage in the Y-connection can be written as follows in abc sequence.
Reduce the equation to find the rms value of the phase voltage.
Here,
In Y-connection, the phase voltages can be written as follows on positive phase sequence abc.
Substitute equation (1) in equations (2), (3) and (4).
The phase voltage
The phase voltage
And
The phase voltage
Or the phase voltage
Calculation:
Substitute
Substitute
Substitute
Or from equation (8) the phase voltage
Conclusion:
Thus, for the abc sequence,
The phase voltage
The phase voltage
The phase voltage
(b)
Find the phase voltages for the acb sequence.
Answer to Problem 1P
For the acb sequence,
The phase voltage
The phase voltage
The phase voltage
Explanation of Solution
Given data:
The phase sequence is acb.
Formula used:
The line voltage in the Y-connection can be written as follows in acb sequence.
Reduce the equation to find the rms value of the phase voltage.
Here,
In Y-connection, the phase voltages can be written as follows on positive phase sequence acb.
Substitute equation (9) in equations (10), (11) and (12).
The phase voltage
The phase voltage
And
The phase voltage
Or the phase voltage
Calculation:
Substitute
Substitute
Substitute
Or from equation (16) the phase voltage
Conclusion:
Thus, for the acb sequence,
The phase voltage
The phase voltage
The phase voltage
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Chapter 12 Solutions
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