GENERATORS

Generators can be identified by numbers with one or two suffix letters.  The number is the generator model followed by a letter which signifies the resistance (A to L used), whilst the additional suffix letter (N to Z) will signify that the generator is mounted in some way.

The resistance letters are:-
A = 500 ohms
B = 450 ohms
C = 400 ohms
D = 300 ohms
E = 200 ohms
F = 110 ohms
G = 60 ohms

Refer to diagram for explanation of the Connection Code - Diagram T. L. 707. or N1200.

Handles are fixed by means of a screw, bayonet connection or by a threaded spindle.  To remove the handle on a threaded spindle, turn the handle anticlockwise - or give it a quick flick anticlockwise.

 
Generator No. 2A

Generator of 500ohms with three magnets.

Connection code K.

Diagram - T. L. 707. or N 1200.

Weight - 5lb 2oz.

Includes:-
1 x Handle, Generator No's 2A, 7, 9, 15, 19, 20 or 21.

Used on the Telephone No's 13 and 25.

Superseded by No. 8A.

 

  
Generator No. 2AN

A wooden cased, wall mounted generator of 500ohms with three magnets.

Connection code K.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Generator No. 2A.
1 x Handle, Generator No. 9.

Superseded by Generator No. 8AN.

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Generator No. 3A

Generator of 500 ohms with four magnets.

Connection code L.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Handle, Generator No. 4.

Superseded by Generator No. 8A.

War Department part - YA6809.

 

  
Generator No. 3AN

Cased generator for table or wall fixing.  The Mark 234 includes a Generator No. 3A.

Connection code L (Mark 234).
Connection code F (Mark 2013A).
Connection code B (Mark N.T.9).
Connection code E (Mark GNH).

Diagram - T. L. 707. or N 1200.

Superseded by Generator No. 8AN.

 

  
Generator No. 4C

2 magnet (Marks 234 and 235) or three magnet (Mark 236).

Coil resistance is 400ohms.

Connection code K.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Handles, Generator No. 6.

Used on the Telephone No's 11 and 13.

Drawing - 62970 (Mark 4).

 


 
Generator No. 4CN

Table or wall fixed generator in a wooden case.

Connection code K.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Generator No. 4C.
1 x Handles, Generator No. 6.

Connection would be via a Cord, Instrument No. 3/13B 54".

Used with Telephone No's 4 and 26.

Made by Ericsson, their part N8480A (diagram N10567) or GEC (diagram KS7172).

Drawing - 8641.

These were also used in Australia.

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Generator No. 4CO

For use on Telephone No. 59 (Mark N.T. 8).

 

  
Generator No. 4CP

Table or wall fixed generator in a wooden case. As the No. 4CN but has a capacitor fitted in the case.

Connection code K.

For external extension stations on circuits connected at the main station to a Bellset, No. 20 or No. 39.

Diagram - N1597.

Includes:-
1 x Generator No. 4C.
1 x Condenser, M.C., No. 1 or No. 102.
1 x Handle, Generator No. 6.

Connection would be via a Cord, Instrument No. 3/13B 54".

These were also used in Australia.

Made by Ericsson, their part N8480 (diagram N10567) or GEC their part C1897 (diagram KS7172).

Drawing - 8641.

Weight - 4lb 10oz.

Click here for an internal view

 

Generator No. 5E

Generator of 200ohms with four magnets.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Handle, Generator No. 12.

 

  
Generator No. 5EN

Wall mounted generator.

Connection code O.

Diagram - T. L. 707.

Includes:-
1 x Generator No. 5E.

 

  
Generator No. 8A

Generator of 500ohms with four magnets.

Connection code K.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Handle, Generator No. 16 (mark 2010).
1 x Handle, Generator No. 13 (mark 234).

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

Drawing - 8800.

Click on the picture for more information

 


 
Generator No. 8AN

For table or wall fixing.

Connection code K.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Generator No. 8A.
1 x Handle, Generator No. 7.

Supersedes Generator No's 2AN, 3AN and 20AN.

Used on Call Bell Systems and when a Generator No. 4 in insufficient.

  
Generator No. 10G

Generator of 60ohms with nine magnets.

Connection code O.

Diagram - T. L. 707. or N 1200.

Used on Call Bell Systems.

  
Generator No. 11A

Generator of 60ohms with nine magnets.

Connection code O.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x double pulley.

 

  
Generator No. 11AN

Generator with "Busy back gear".

Includes:-
1 x Generator No. 11A.

 

  
Generator No. 12A

Generator of 500 ohms with four magnets.

Connection code P.

Diagram - T. L. 707. or N 1200.

 

  
Generator No. 12AN

Generator with 4 magnets for wall fixing.

Connection code P.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Generator No. 12A.

 

  
Generator No. 13F

Generator of 110 ohms with five magnets.

Connection code K.

Diagram - T. L. 707. or N 1200.

 

  
Generator No. 13FN

Wall mounted generator of 110ohms with five magnets, used on fire systems.

Connection code K.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Generator No. 13F.
1 x Handle, Generator No. 19.

Used on Call Bell Systems.

 

  
Generator No. 15

Generator of 500 ohms with four magnets.

Connection code F.

Diagram - T. L. 707. or N 1200.

Used on switchboards.
AN, AP and AQ variants.

Obsolete in 1947.

Superseded by Generator No. 26....

 

  
Generator No. 20A

Generator of 500 ohms with four magnets.

Connection code D or F.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Handles, Generator No. 13.
1 x Handles, Generator No. 16 (Mark 2013).

 

  
Generator No. 20AN

Table or wall fixing.

Connection code D.

Diagram - T. L. 707. or N 1200.

Includes:-
1 x Generator No. 20A.

Superseded by Generator No. 8AN.

 

  
Generator No. 23A

Generator of 500 ohms with four magnets.

Connection code C.

Diagram - T. L. 707. or N 1200.

 

  
Generator No. 24A

Generator of 500 ohms with four magnets.

Connection code M.

Diagram - T. L. 707. or N 1200.

 

  
Generator No. 26A

Generator of 500ohms with one magnet (Alnico).  They are generally installed inside apparatus like telephones and switchboards and are supplied without any casing.

Connection code K.

Drawing - 62257

Diagram - T. L. 707. or N 1200.

Specification - D1529.

In general use from the 1930's onwards.

These superseded Generator No's 4C & 8A.

Ericsson Part No. N4649.

There were three iterations of this generator: Mark 1, Mark 2 and Mark 3.

War Department number - YA2287.

 


 
Generator No. 26AN

Generator for table or wall fixing.  The four case fixing screws are captive.

Includes:-
1 x Generator No. 26A.
1 x Handle Generator No. 20.

Ericsson Part No. N8486A1.

Drawing - 63753.

Diagram - LD121 (Mark 3).

Specification - D1529.

War Department number - YA2287

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Generator No. 26AP

Generator for table or wall fixing.   The four case fixing screws are captive. Similar to the No. 26AN but has a capacitor fitted.

Used on extension telephones, on long circuits, connected at the main station to Bellset No. 20 when Generator No. 4CP is not powerful enough.

Includes:-
1 x Condenser, M.C., No. 102.
1 x Clip, No. 14.
1 x Generator No. 26A.
1 x Handle, Generator No. 20.

Ericsson Part No. N8486A2.

Drawing - 63753.

Diagram - LD121.

Specification - D1529.

Click here for more information

 

Generator No. 28H

Generator - uncased.

Includes:-
1 x Handle, Generator No. 19.
1 x Generator No. 28H.

Used on Call Bell Systems.

Drawing - 62370 (Mark 1).

Specification - D1721.

 

  
Generator No. 28HN

For table or wall fixing and fitted with a case No. 54.

Used in call-bell systems.

Includes:-
1 x Case No. 54.
1 x Handle, Generator No. 19.
1 x Generator No. 28H.

Used on Call Bell Systems.

Drawing - 63269 (Mark 1).

Diagram - LD121 (Mark 1).

Specification - D1721.

The Generator No. 28HN (Mark 1) was made by Ericsson, their part number N8486C.

 

  

Generator No. 106

Click on the picture for more information.

 

 

 

 

 

 
 
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Last revised: November 03, 2025

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