Nikola Tesla Books
Books written by or about Nikola Tesla
| Number of turns of the regulating coil included in circuit | E.m.f. across two primary turns plus the connections, plus flexible cable + one half of one turn reg. coil | Difference of e.m.f. between successive readings: | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| first series of readings | second series | third series | fourth series | average | ||||||||||||||
| 23 1/2 | 15.873 | 15.928 | 15.928 | 15.928 | 15.914 |
|
||||||||||||
| 22 1/2 | 15.706 | 15.706 | 15.706 | 15.706 | 15.706 | |||||||||||||
| 20 1/2 | 15.318 | 15.263 | 15.34 | 15.318 | 15.310 | |||||||||||||
| 18 1/2 | 14.929 | 14.8185 | 14.929 | 14.929 | 14.901 | |||||||||||||
| 16 1/2 | 14.4855 | 14.4855 | 14.4855 | 14.4855 | 14.4855 | |||||||||||||
| 14 1/2 | 14.119 | 14.0415 | 14.1525 | 14.097 | 14.102 | |||||||||||||
| 12 1/2 | 13.764 | 13.7085 | 13.764 | 13.764 | 13.75 | |||||||||||||
| 10 1/2 | 13.3755 | 13.3755 | 13.3755 | 13.3755 | 13.3755 | |||||||||||||
| 8 1/2 | 13.0425 | 12.9537 | 13.009 | 13.0425 | 13.012 | |||||||||||||
| 6 1/2 | 12.7095 | 12.654 | 12.7095 | 12.7095 | 12.6956 | |||||||||||||
| 4 1/2 | 12.3765 | 12.3765 | 12.3765 | 12.3765 | 12.3765 | |||||||||||||
| 2 1/2 | 12.1545 | 12.1212 | 12.1875 | 12.1545 | 12.1544 | |||||||||||||
| 1/2 | 12.00 | 12.00 | 12.00 | 12.00 | 12.00 | |||||||||||||
Ï in these readings was smaller than 880.
Note: When reduced to the same e.m.f. across the two primaries and connections, 1/2 turn and flexible cable the average values agree fairly well with the readings before recorded. The table prepared on the bases of the values before found will be accurate enough for all ordinary estimates. Both sets of readings show that there is about 0.2 volt variation per turn, the few first turns excepted.
269
November 8
The primary inductance values cited are from November 5th. The other values given in the table do not agree with those derived from the measurements of October 30th. Also, earlier data do not include values for half a turn of the regulating coil. It must therefore be concluded that the measurements from which the tabulated values were calculated are not described in the diary.
It seems that in measuring inductance from voltage, current, frequency and resistance Tesla had difficulty because of unreliability of the frequency determination. He therefore used the voltage ratio, when it is only necessary for the frequency to be constant. By this method he measured the inductance of the regulating coil plus connections, for various numbers of turns.
November 8
He attaches the table of calculated primary and regulating coil inductances plus that of the connections as a function of number of turns. The values for the primary are those of Nov. 5. Other values given in the table do not match those obtained on the basis of measurement data of Oct. 30. Also in previous data the values for the regulatory coil turns halves are not given.
From all this it follows that the measurement results from which the calculated values are obtained and which are shown in the attached table are not given in the notes.
It seems that Tesla was not satisfied with the inductance measurements on the basis of voltage, current, frequency and the resistance due to uncertainty of determining the frequency itself. That is why he applied the method of voltage ratio where it is only important that source frequency is not changed during the measurements.
By this method he performs the measurements in order to determine the regulating coil and the connection inductance for the various number of turns of the coil.
