Edgerton Lab Notebook 03, Page 03:
February 15, 1930
- Page start date:
- February 15, 1930
- Content type:
- diagram,notes
- Transcription:
- Oscillographic Measurement of the Angular Displacement in a Syn. Machine
Feb 15, 1930
H.E. Edgerton
An extra synchronous machine on the shaft of a machine being tested gives a voltage which [-is in-] has a definite relationship with the induced [?] E of that machine [-being tested since-] since the field pole have a rigid relationship. The open-circuit voltage from this extra machine is combined vectorially with the terminal [-al-] voltage of the machine under test and a trigonometric 3 voltage problem gives the angular displacement.
[diagram]
[equations]
This method has been used in the past with great success.
When the rotor is slipping, for instance during a transient following a sudden load, then the length of E[sub]e depends directly upon the speed and some small errors are introduces. The expression for angle is then [equation] where s is the slip. The slip is usually less than 2% so this is ordinarily neglected.
- Keywords:
- displacement; machine; measurement; oscillographic; shaft; synchronous; trigonometric; voltage
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