ericsson review - History of Ericsson - History of Ericsson

Fig. 9
x 5: ' ! "
Panel instrument of large type
left, for external fitting; right, for flush fitting
in panel
Fig. 10
Curved front instrument
Fig. 11
Small instruments
86
enclosed. The colour is dull black. The dimensions are 154 111111X70 nun over
flanges. The curved front instruments may be mounted with the scale horizontal
or upright.
The large panel instruments and the curved front instruments are fitted with
measuring systems of the large type, with one exception, the panel instrument
with 110 mm base-plate diameter for DC measurements only, this having the
small moving coil system.
The measuring accuracy for both moving coil instruments and moving iron
instruments is ± 1.5 %. Test voltage is 2 500 V.
Small Instruments
The small instruments, Fig. 11, are intended solely for flush mounting on
x 3959 panels, the sizes being 65 mm and 90 mm according to the diameter of flange.
The cases are normally of black pressed compound. The small instruments are
made only with measuring systems of small types.
These instruments also are provided with zero-restoring screw on the front. In
addition thev are provided with iron screen against disturbing action of
outside fields.
The measuring accuracy for the moving coil instrument is from +1.5% up to
± 0.5 % and for the moving iron instruments 1.5 %. Test voltage is 2 500 V.
Marine Instruments
The marine instruments, Fig. 12, have two kinds of case. One is designed for
flush mounting with rear connections, the other for external mounting with
front connection over a cable box. The instruments are watertight and made
to meet the Swedish Admiralty stipulations; they stand an excess pressure
of 1 at. As in preceding instruments the normal colour is dull 'black. The
cases have a flange diameter of 195 mm.