GENERATORS


Click here for Generator Handles

The small AC generators for telephone installation work can be identified by numbers with one or more suffix letters.  The first suffix letter will signify the resistance (Letters A to L) and the additional suffix letters (M to Z) the way the generator is mounted.

Resistance (Ohms) suffixes are:-
A = 500
B = 450
C = 400
D = 300
E = 200
F = 110
G = 60

Each generator also had a wiring connection code - Click here for the code connection diagrams.
 

Generator No. 2A

Three magnet generator of 500ohms.

Includes a Handle, Generator No. 9.

Connection code K.

Diagram - TL707.

 

 
Generator No. 2AN

Three magnet generator of 500ohms in a wooden case.

Dimensions - 7.1" x 6.1" x 4.75".

Includes a Handle, Generator No. 9.

Connection code K.

Diagram - TL707.

 

 
Generator No. 3A

Four magnet generator of 500ohms.

Includes a Handle, Generator No. 4.

Connection code L.

Diagram - TL707.

 

 
Generator No. 3AN

Four magnet generator of 500ohms in a wooden case.

Includes a Handle, Generator No. 4.

Connection code L, F, B or E.

Diagram - TL707.

 

Mark Case dimensions Connection Code
234 - L
2013A 7.5" x 7" x 6" F
NT 9 8" x 6.5" x 5" B
GNH 7" x 7" x 4.75" E
Generator No. 4C

Two magnet (Marks 234 & 235) and three magnet (Mark 236) generator of 400ohms.

Includes a Handle, Generator No. 6.

Connection code K.

Diagram - TL707.

 


 
Generator No. 4CN, CO & 4CP

Effectively a Generator 4C in a wooden case.

Generator No. 4CO was used in the Telephone No. 59 Mark NT8.

Generator No. 4CP had a Condenser No. 102 fitted.

Made by Ericsson. Diagram dated 1932.
N8480 - No. 4CP.
N8480A - No. 4CN.

Dimensions:-
Case - CN & CP - 6.1" x 4.3" x 7.1".
Base - CO - 4" x 3.5" x 0.3".

 


 
Generator No. 5E

Four magnet generator of 200ohms.

Includes a Handle, Generator No. 12.

Connection code O.

Diagram - TL707.

 

 
Generator No. 5EN

Four magnet generator of 200ohms in a wooden case.

Includes a Handle, Generator No. 12.

Connection code O.

Diagram - TL707.

Dimensions - 11.5" x 7.4" x 5.75".

 

 
Generator No. 8A

Four magnet generator of 400ohms.

Includes a Handle, Generator No. 16 (Mark 2010) or 13 (Mark 234).

Connection code K.

Diagram - TL707.

Superseded Generator No's 2A, 3A and 20A.


 
Generator No. 9A

Four magnet generator of 500ohms.

Includes a Handle, Generator No. 16.

Connection code O.

Diagram - TL707.

 

 
Generator No. 12A

Four magnet generator of 500ohms.

Connection code P.

Diagram - TL707.

 

 
Generator No. 12AN

Four magnet generator of 500ohms.

Connection code P.

Diagram - TL707.

Dimensions - 8" x 7.75" x 5.1".

 

 
Generator No. 13F

Five magnet generator of 110ohms.

Connection code K.

Diagram - TL707.

 

 
Generator No. 13F

Five magnet generator of 110ohms in a wooden case.

Connection code K.

Diagram - TL707.

Dimensions - 10" x 7.25" x 6.25".

 

 
Generator No. 15A

Five magnet generator of 500hms.

Connection code F.

Diagram - TL707.

Dimensions - 10" x 7.25" x 6.25".

 

 
Generator No. 15A

Five magnet generator of 500hms.  Fixed to a base plate and fitted in switchboards

Connection code F.

Diagram - TL707.

Dimensions:-
AN, AO & AP - 5.5" x 4.25".
AQ - 6.3" x 4.1".

 

 
Generator No. 20A

Five magnet generator of 1500hms.

Includes a Handle, Generator No. 1 (Mark 234) or 16 (Mark 2013).

Connection code D or F.

Diagram - TL707.

 

 
Generator No. 23A

Four magnet generator of 500ohms.

Connection code C.

Diagram - TL707.

 

 
Generator No. 24A

Four magnet generator of 500ohms.

Connection code M.

Diagram - TL707.

Used in Telephone No's 89 and 104.

 

 
Generator No. 26A

Universal generator

ETL Part Number N4649.
 


 
Generator No. 26AN

Desk top generator - click here for more information
 

 


 
Generator No. 26AP

Desk top generator - click here for more information
 

 


 
 
 
 

 

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

Last revised: December 31, 2023

FM