MACHINES & SWITCHBOARDS
Issue 2, 11/4/62
CONVERTERS, RINGING Nos. 4, 5, 6 AND 7
1. Scope of Instruction
The output of the Converters, Ringing, Nos. 4, 5 and 6 is a nominal 60v, and the output of the No. 7 a nominal 50v. Each converter will ring up to four Bells No. 59A in series with a 2 uF capacitor.
Bell No. 64E, which has a loud-sounding gong, works very efficiently with these converters. Bell No. 67A, which has a heavy movement, also responds reasonably well if a 2 uF capacitor is connected in series.
The numbers of Bells No. 59A, each connected in series with a 2 uF capacitor, which can be rung in parallel by the output of the converters is given in Table 1.
When the loading on the output terminals is increased beyond full load, the output voltage falls rapidly and the production of 25 c/s ceases. On removing the excess load, the oscillations restart. This provides a useful self-protecting feature.
The Converter, Ringing, No. 5 is for use at P.B.X.s where there are 5 to 20 operatorsí positions or at 20-line Multiphone switchboards. Electrically, it can be considered as the equivalent of the Converters, Ringing, Nos. 2A and 2B. Physically, however, there is some difference as both the No. 4 and No. 5 are for wall-mounting. By the use of two Mountings D 91065, a Converter, Ringing, No. 4 or No. 5 may be mounted on a standard 19-in, rack, such as Racks, Apparatus, No. 42.
The Converter, Ringing, No. 6 is for use at P.B.X.s where there are more than 21 operatorsí positions or at Multiphone switchboards having 21 to 60 lines. It can be considered as an equivalent of the Con≠verter, Ringing, No. 3. Physically there are some differences and the Converter, Ringing, No. 6 may be mounted on a wall or direct on a standard 19-in rack. The Converter, Ringing, No. 7 is for use at non-multiple installations.
Last revised: November 29, 2010