Improvements in Electric Meter Apparatus.
Year: 1897

page_text: Date of Application, 15th June, 1897-Accepted, 24th July, 1897
Improvements in Electric Meter Apparatus.
I, EUSTACE OXLEY of 1242-11th Street, North West Washington, United States
of America Electrical Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
It is well known that very few electric meters register correctly for small loads.
For example, fifty ampere meters usually give no registration on less than five lamps
and inaccurate registration when only a few more lamps are in action.
Where large
size meters are used, as for instance for theatres, hotels, public. buildings, or large
private residences, ten twenty or more lamps can be burned continuously without any
meter indication whatever.
In a system employing even a moderate number of meters of high capacity, upon
circuits where each consumer burns a small number of lamps day and night, the
aggregate annual loss to the establishment which supplies electricity is very great.
The object of my invention is to remove this cause of loss by means of very simple
character, comprising a small number of mechanical parts which do not deteriorate
by use, or age, in accuracy, or promptness of response; whereby every unit of work,
or strength of current that flows over the circuit shall be correctly registered, without
regard to the normal load of the circuit, or the actual load.
It is another characteristic feature of my invention that it is automatic in action,
requiring no attention or watching, and after being once installed it remains in proper
condition and operation as long as the parts of the meter endure.
I shall describe my invention referring to the accompanying drawings.
Fig. 1 is a diagram with a switch in perspective, shewing my invention applied to
an ordinary electric circuit.
Fig. 2 is a side elevation of the switch.
Fig. 3 is a plan of the same.
Fig. 4 is a vertical section shewing a modified form of switch.
Fig. 5 is a plan of the same.
Fig. 6 is a diagram shewing the modified switch connected in an electric circuit.
1, indicates an electric ineter, which may be of any known kind.
2, denotes a three-wire circuit having its positive and negative service wires led
into the meter 1.
At the right hand of Figs. 1 and 6 is shewn a portion of the positive and
negative branches 3 and 4 of the house-circuit, upon each of which a few lamps 5
and 5 are shewn.
Assuming that the meter 1 is of any large current capacity say, for example, one
hundred and fifty amperes, then the number of lamps 5 or 5 shewn could certainly
be burned day and night, continuously, year after year, without any record being
made by the meter, and as time passes a still greater number of lamps could be
burned without record. In order to remove this source of great and increasing loss
of legitimate profits, I interpose in the service wires, at any suitable point before
they enter the meter 1, a suitable automatic switch S (Fig. 1).
The positive and negative wires are led to posts 6 and 7 and thence around the
cores 8 of an electro magnet and to terminals 9 and 9 whence wires 10 and 12 are
Fig. 5 is a plan of the same.
Fig. 6 is a diagram shewing the modified switch connected in an electric circuit.
1, indicates an electric ineter, which may be of any known kind.
2, denotes a three-wire circuit having its positive and negative service wires led
into the meter 1.
At the right hand of Figs. 1 and 6 is shewn a portion of the positive and
negative branches 3 and 4 of the house-circuit, upon each of which a few lamps 5
and 5 are shewn.
Assuming that the meter 1 is of any large current capacity say, for example, one
hundred and fifty amperes, then the number of lamps 5 or 5 shewn could certainly
be burned day and night, continuously, year after year, without any record being
made by the meter, and as time passes a still greater number of lamps could be
burned without record. In order to remove this source of great and increasing loss
of legitimate profits, I interpose in the service wires, at any suitable point before
they enter the meter 1, a suitable automatic switch S (Fig. 1).
The positive and negative wires are led to posts 6 and 7 and thence around the
cores 8 of an electro magnet and to terminals 9 and 9 whence wires 10 and 12 are

page_text: led to a meter 1, of a suitable current capacity preferably small compared to that of
the meter 1.
From the second meter 1ª, wires 13 and 14 go to the distribution circuits.
The circuit of the meter 1ª is completed without the action of the switch S which
may be of the form shewn in Figs. 1, 2 and 3, or in Figs. 4, 5 and 6.
The switch is provided with insulated terminals 15 and 16, from which wires 17
and 18, connect to the meter 1.
The outgoing wires 19 and 20 are led to the system of distribution.
The terminals 9, 9 and 15 and 16 are mercury cups, and the switch has an
armature 21 which can be attracted by the magnet 8 this armature being on a switch
lever 22, pivotted at 23 on a support 24, the armature 21 being normally drawn away
from the magnet by a spring 25, which may be adjustable.
Upon the end of the lever 22, is a crosshead 26 carrying an insulated fork 27, the
prongs of which, when the armature 21 is attracted, enter the mercury cups 9 and 9ª
and 15 and 16 thus closing the circuit of the first meter 1.
The lever 22 has an adjustable back-stop 28. From the terminals 9 and 9ª wires
10 and 12 lead to the second meter 1ª whence wires 13 and 14 lead to the system of
distribution.
While the switch S is in the condition shewn in Fig. 2 the circuit of the meter 1 is
open the shunt circuit 10-12, which includes the second meter 1ª being closed. Ifa
small load is thrown upon the circuit, the current flows through the terminals 6 and 7,
though the coils of the magnet 8 to the terminals 9 and 9 then by the shunt wires
10 and 12 through the meter 1ª and the wires 13 and 14 to the lamps. But when
the current strength is such as to energise the magnet 8 sufficiently to attract the
armature 21, the switch lever 22 is moved down and the conductors 27 dipping into
the mercury connect 9 to 15 and 9 to 16 thus completing the circuit through the
ineter 1 which then begins to register.
In this automatic action, no provision is made for cutting the meter 1ª out after
the meter 1 is brought into action; this might be done, but by leaving both in circuit
there is much less tendency to sparking.
The second meter 1* registers only a fraction of the current consumption but the
aggregate registration of both meters always gives an accurate and reliable record of
the current consumed, at all loads.
I have shewn, in Figs. 4, 5 and 6, a modified form of switch. It comprises two
isolated reservoirs 29 and 30, each containing mercury 31. Resting on the mercury
without material pressure are diaphragmns 32 and 33. Beneath the reservoirs is an
electro magnet 8, and an armature 34 suspended by a central stem 35 urged upwards
by a spring 36. The stem is connected to a crosshead 37, the ends of which have
stems that enter the reservoirs and rest on the diaphragms 32 and 33.
Communicating with the mercury in the reservoirs are insulating chambers 38, in
which hang contact terminals 39 of less diameter than the chambers.
The terminals 6, 7, 9, 9, 15 and 16 being connected as described, when the
armature 34 is attracted by the electro-magnet the mercury shoots up in the contact
chambers 38 until it reaches the terminals 39 closing the circuit of the meter 1.
By properly uniting the contacts 39 and chambers 38, the containers of the
mercury can be tightly sealed, perfectly excluding dust and moisture and preventing
waste of mercury by volatilisation.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, I declare that what
I claim is:
-
1. In a system of electrical distribution the combination with two electric meters,
the one of greater current capacity than the other, a switch which normally opens
the circuit of the greater meter, and normally closes the shunt circuit of the less
meter, and means whereby the current energy is employed to close the circuit of the
greater meter, substantially as set forth.
2. In an arrangement of electric meters such as is referred to in the preceding

page_text: claim, a switch constructed and operating substantially as described with reference to
Figs. 1, 2, and 3.
3. The modified switch arranged and operating substantially as described with
reference to Figs. 4, 5 and 6.
Dated thin 15th day of Tuna 1907
ABEL & IMRAY,
Agent for the Applicant.