The tip of each magnet, as well as the edge of each tone wheel, is coated with lacquer to prevent
corrosion, for, should oxidation set in, the change in tooth shape would introduce irregular
frequencies.
Locations of the various magnet and coil assemblies are shown in Figure 12.
They are identified by their frequency numbers, and the broken line between any two numbers
indicates that these two frequencies are supplied by one tone wheel assembly.
Each magnet gap is set at the factory with the set screw partially loosened, while observing an
output meter. Experience has shown that the magnets seldom need adjustment and that setting
them without proper equipment involves danger of damaging both magnet and wheel. Therefore it
is not recommended that the service man attempt this adjustment.
GENERATOR FILTERS
As a means of eliminating any vagrant harmonics that may be present, there are filters consisting
of small transformers and condensers associated with certain frequencies. The transformers have
a single tapped winding, and this tap is grounded, so one side, which is connected to the
corresponding magnet coil through a condenser, forms a resonant circuit for the fundamental
frequency of that coil. This tends to emphasize the fundamental and suppress harmonics.
Locations of these transformers are shown in
Figure 13
.
They are also shown in the schematic.
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