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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Test results of standard and U.S.A. Bosch ignition coils.

Identifier  ExFiles\Box 61b\4\  scan0070
Date  25th October 1921
  
X.4275.
25.10.21.

X.3445.
X.4079 TEST RESULTS OF STD & U.S.A. BOSCH IGNITION COILS.
X.4275.

| Coil. | PRIMARY. | | | | SECONDARY. | | | | Remarks. |
|---|---:|---:|---:|---:|---:|---:|---:|---:|---|
| | Resis. (W) | Imped. at 50 (W) | Reac. at 50 (W) | Induc. (hys) | Resis. (W) | Imp. at 50 (W) | Reac. at 50 (W) | Induc. (hys) | |
| 40/50 Z. | | | | | | | | | |
| 2197. | .866 | 4.30 | 4.22 | .0134 | 5362 | 12000 | 10730 | 34.2 | |
| 2209 | .896 | 4.42 | 4.33 | .01378 | 5210 | 12100 | 10910 | 34.7 | |
| 149 | .857 | 4.65 | 4.565 | .01432 | 5540 | 14750 | 13680 | 43.5 | |
| U.S.A. B. | | | | | | | | | |
| Original. | .75 | 2.18 | 2.045 | .00643 | 4350 | 14580 | 13900 | 44.2 | p =50.7 x 2 TT |
| 3075 | .66 | 2.16 | 2.06 | .00655 | 2150 | 8350 | 8080 | 25.7 | p =50.0 x 2 TT |
| 3076 | .66 | 2.19 | 1.99 | .00632 | 2200 | 8760 | 8490 | 27.0 | " |
| 3077 | .64 | 1.97 | 1.86 | .00591 | 2200 | 8590 | 8300 | 26.4 | " |
| R.R. B. | | | | | | | | | |
| B Old. | .492 | 3.213 | 3.175 | .0101 | 8130 | 18430 | 16550 | 52.7 | |
| GB 1 | .631 | 3.131 | 3.065 | .00976 | 4320 | 10310 | 9350 | 29.75 | } Recd. Feb 1922. |
| GB 2 | .637 | 3.04 | 2.975 | .00946 | 3890 | 8950 | 8030 | 25.5 | } Low Secondary Turns |
| GB 3 | .627 | 3.03 | 2.962 | .00944 | 3975 | 9720 | 8380 | 26.65 | } |
| GB 4 | .630 | 3.04 | 2.972 | .00946 | 4238 | 9810 | 8850 | 29.15 | } |
| GB 5 | .633 | 3.15 | 3.085 | .00982 | 3908 | 8858 | 7930 | 25.25 | } |
| SB{Mr Bull/Mr Bannister} 1 | .610 | 2.89 | 2.822 | .00898 | 7720 | 18510 | 16820 | 53.5 | |
  
  


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