COIL, INDUCTION No. 27


This Induction Coil consist of five windings of:-

  1. 35 Ohms (2600 turns of 33 SWG) (tags 1 & 2).

  2. 75 Ohms (1800 turns of 37 SWG) (tags 3 & 4).

  3. 30 Ohms (800 turns of 36 SWG) (tags 3 & 5).

  4. 30 Ohms non-inductive (tags 3 & 7).

  5. 30 Ohms non-inductive (tags 5 & 6).


Inductive windings to be in an anti-clockwise direction looking at the end of the coil marked 1,3,5,7.

Core
Satisfactory induction coils may be made with cores of 0.022" (25 SWG) well annealed charcoal iron wire left black from the annealing process.

Both ends of the coil to be sealed with approved varnish.

Winding Resistance (tolerances)
First winding not greater than 40 ohms.
Second winding not greater than 82.5 ohms.
Third winding not greater than 35 ohms.
Fourth winding, 30 ohms +/- 5%.
Fifth winding, 30 ohms +/- 5%.

Drawing - 62207.


 

 
 
BACK Home page BT/GPO Telephones Search the Site Glossary of Telecom Terminology Quick Find All Telephone Systems

Last revised: February 21, 2023

FM