Ericsson DIALOG - Ringer Unit Mechanism and Sound

3.2 Ringer
8
the cord inlet in the base plate, a hole has been made in the raised
edge. The cords, which can thereby be rem oved one at a time,
lock each other and ensure a tight packing.
Fig. 7
The base
plate from
above
The ringer mechanism (fig. 8 and 9) is mounted on a plate (1)
provided with three tabs which are inserted in slots in the base
plate. In addition there is a hole in the centre cf the ringer
mechanism plate in which a projecting stud on the base plate fits
when the ringer mechanism has been correctly l oca ted.
Fig. 8
The bell
unit
The ringer is connected to the screw terminals of the trans- ·
mission unit by means of two PVC insulat ed conductors . eq uipp ed
with cable lugs. The ringer is of the polariz ed type with a single
winding (3) and a small AlNiCo permanent magnet (2). Th e flux
generated by the permanent magnet and the flux. or iginatin g from
the ringing current. is superimposed only in the ''air gap' ', which
gives maximum signalling efficiency. The "air gap" is easy to
adjust and the coil is replaceable.
The coil former is made of Formaldehyde-plastic and wound with
copper wire. insulated by shellac.
All the iron parts are zinc-electroplated with yellow cro mate
coating and laquered.
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