battery, rather more of a finer gauge of wire must be employed to wind the magnets than that herein recommended, unless, indeed, relays be used in conjunction with the bells.
Table
Showing proportions to be observed in the different parts of electric bells.
| Diameter of Bell. | Length of Magnet Cores. | Diameter of Magnet Cores. | Length of Bobbin. | Diameter of Bobbin Head. | B. W. G. of Wire on Bobbin. |
|---|---|---|---|---|---|
| 2½'' | 2'' | 5/16'' | 1¾'' | ¾'' | 24 |
| 3 | 2¼ | ⅜ | 2 | ⅞ | 24 |
| 3½ | 2½ | 7/16 | 2¼ | 1 | 22 |
| 4 | 2¾ | ½ | 2½ | 1⅛ | 22 |
| 4½ | 3 | 9/16 | 2¾ | 1¼ | 20 |
| 5 | 3¼ | ⅝ | 3 | 1⅜ | 18 |
| 5½ | 3½ | 11/16 | 3¼ | 1½ | 16 |
| 6 | 3¾ | ¾ | 3½ | 1⅝ | 16 |
| 6½ | 4 | 13/16 | 3¾ | 1¾ | 16 |
| 7 | 4¼ | ⅞ | 4 | 1⅞ | 16 |
| 7½ | 4½ | 15/16 | 4¼ | 2 | 14 |
| 8 | 4¾ | 1 | 4½ | 2⅛ | 14 |
| 8½ | 5 | 1-1/16 | 4¾ | 2¼ | 14 |
| 9 | 5¼ | 1⅛ | 5 | 2⅜ | 14 |
| 9½ | 5½ | 1-3/16 | 5¼ | 2½ | 14 |
| 10 | 5¾ | 1¼ | 5½ | 2⅝ | 14 |
| 10½ | 6 | 1-5/16 | 5¾ | 2¾ | 12 |
| 11 | 6¼ | 1⅜ | 6 | 2⅞ | 12 |
| 11½ | 6½ | 1-7/16 | 6¼ | 3 | 10 |
| 12 | 6¾ | 1½ | 6½ | 3⅛ | 10 |
Fig. 33 A.