Improvements in Electricity Meters or Measuring Apparatus.
Year: 1899

page_text: COMPLETE SPECIFICATION.
Improvements in Electricity Meters or Measuring Apparatus.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate, West-
minster, in the County of London, Electrical Engineers, do hereby declare the
nature of this invention (as communicated to us from abroad by Siemens & Halske
Aktien Gesellschaft, of Markgrafen Strasse, No. 94, Berlin, S.W., Electrical
Engineers) and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
-
In electricity meters or measuring apparatus with oscillating or rotating parts
it is essential that the motion of the said parts should be rendered as independent
as possible of frictional resistance to such motion as only in that case can a high
degree of sensitiveness be obtained and the measurements be rendered inde-
pendent of concussions to which the apparatus may be subjected.
As is well known the so called friction of a state of rest is greater than that of
motion, the gradual transition from the one to the other being mainly perceptible
at very slow speeds.
With electricity meters or measuring apparatus such friction exercises a dis-
turbing influence because the moving parts only follow a greater or less change
in the directing force.
This condition is similar to that of driving gear having more or less dead play.
In order to overcome this starting friction it is a general practice to tap indi-
cating instruments when exact readings are to be taken.
For
The present invention relates to a device by which such meters are subjected
automatically to slight vibrations in a very simple and effective manner.
this purpose according to one arrangement the axle of the instrument is pressed
either by gravity or by a spring against a foot or end bearing mounted on a spring,
and vibratory motion of the latter having been set up such vibrations are con-
tinuously maintained in the direction of the said axle."
On the accompanying drawing are shewn by way of example diagrammatic
views of various arrangements for carrying the said invention into practice.
In Figs.
and 2, A A is the vertical axle of a measuring instrument carried
in bearings L L, a blade spring F fixed at D has a step bearing H for supporting
the lower pivot and carries a solid iron armature B, situated opposite an electro-
magnet C.
For imparting a vibratory motion to the spring F there is provided, in the
case of a continuous current, any suitable known make and break device, as indi-
cated at Fig. 1 and in order to prevent sparking as much as possible at the con-
tact K the arrangement is such that the electromagnet winding is short circuited
behind a suitable resistance W on the attraction of the armature.
The electromagnet C can be excited either by a special galvanic element E or
by any other available source of current.
In the case of measuring apparatus for alternating currents a make and break
device is not required, as shewn at Fig. 2.
If the electromagnet core C be made of laminated iron and the armature B of

page_text: solid iron, the spring F will have a solid vibratory motion imparted to it as the
magnetism of the armature B, being subject to eddy currents, will lag behind
that of the electromagnet C so that the latter will already have its polarity
reversed while B still possesses the same polarity and in this way a strong attrac-
tion will be followed by an equally strong repulsion.
For promoting the formation of eddy currents, copper pins may advantageously
be inserted in holes in the armature B or this may be provided with short cir-
cuited windings.
The vibrations of the spring F are transmitted to the axle A of the measuring
instrument, so that it has a longitudinal reciprocating motion imparted to it in
its bearings L L.
Experiments have shewn that by this means the friction of rest is almost
entirely done away with and the sensitiveness of the instrument increased in
a very high degree.
Fig. 3 shews in plan an arrangement of the apparatus for an instrument with
horizontal axis. In this case a second spring F is provided as abutment for the
end of the second pivot of the axle, the action of such spring being substituted
for that of gravity acting upon the spindle in the vertical arrangement, where
however such a second spring might also be provided if necessary.
The arrangement is otherwise the same as at Fig. 2.
Instead of imparting vibrations to the moveable part of the measuring instru-
ment, the bearings L might be connected to the vibrating spring and arranged
so as to vibrate with it. This vibratory motion can either take place in the
longitudinal direction of the axis, or the bearings may have vibrations in a rotary
direction imparted to them. Fig. 4 shews an arrangement of this kind.
bearing L is arranged to turn with a very small amount of play in the holder G,
in following the vibratory motion of spring F, and it is acted upon by two oppo-
site springs F F2 tending to maintain it in the middle position.
The
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. In electricity meters or measuring apparatus having oscillating or rotating
parts, the arrangement of such parts in combination with an electromagnet in
such manner that either the reciprocating or revolving parts or their bearings
are automatically set in vibratory motion by means of the electromagnet, for the
purpose of reducing the detrimental effects of frictional resistance, substantially
as described.
2. In electricity meters such as are referred to in the first claim the arrange-
ment of the electromagnet and parts in connection therewith, whereby these are
made to impart a reciprocating motion to the oscillating or rotating part in the
longitudinal direction of its axis substantially as described with reference to
the drawings.
3. In electricity meters such as are referred to in the first claim, the arrange-
ment of the electromagnet and parts in connection therewith whereby the bear-
ings of the oscillating or rotating axle have a vibratory motion imparted to them
either in the longitudinal direction of its axis or in a rotary direction at right
angles to such axis, substantially as described with reference to the drawings.
Dated this 18th day of April 1899.
ABEL & IMRAY,
Agents for the Applicants.