Improvements in Apparatus for Testing Electric Primers, Batteries and Cells.
Year: 1899

page_text: Date of Application, 19th Apr., 1899
Complete Specification Left, 19th Jan., 1900-Accepted, 7th Apr., 1900
Improvements in Apparatus for Testing Electric Primers, Batteries
and Cells.
We, GORDON COLQUHOUN FRASER, Lieutenant in Her Majesty's Navy of Her
Majesty's ship "Vernon," stationed at l'ortsmouth, in the County of Hampshire,
and GEORGE KEITH BULLER ELPHINSTONE, of the Firm of Elliott Brothers, of
101, St. Martin's Lane, in the County of London, Electrical Engineer, do hereby
declare the nature of this invention to be as follows:-
Our apparatus is constructed for the purpose of testing firing primers to
determine the actual current required to fire them and also whether they are
in proper condition and further for facilitating the testing of batteries to ascer-
tain if they are in a proper state of efficiency.
The apparatus consists of a dead beat ammeter movement mounted in a case and
provided with a pointer moving over a scale. Two terminals are provided on the
top of the case one of these terminals is joined to the coil of the ammeter the
other end of the ammeter coil being joined to an adjustable rheostat, the other
extremity of which is brought up to the second terminal on the outside of the
case and fitted with a plug and plug plate if desired, the ammeter movement
and rheostat being thus connected in series.
The rheostat is capable of being varied throughout a range of about 50 ohms.,
and values are assigned to the different positions along this resistance, so that
the current which any battery gives through a particular resistance can easily
be read off on the ammeter scale.
A spring is provided on the moving part of the rheostat so as to keep the
whole of the resistance in circuit when the instrument is left to itself, and a
plug and plug plate can also be employed as an extra safety arrangement if
desired.
The scale of the ammeter can be marked off in actual current measurements,
and also with special marks at certain points to facilitate the rapid testing of
batteries and primers.
The amount of resistance in the circuit of the instrument at any time can be
read off from the face of the instrument.
GORDON COLQUHOUN FRASER,
G. K. B. ELPHINSTONE.

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Testing Electric Primers, Batteries,
and Cells.
"
We, GORDON COLQUHOUN FRASER, Lieutenant in Her Majesty's Navy of Her
Majesty's ship Vernon," stationed at Portsmouth, in the County of Hampshire,
and GEORGE KEITH BULLER ELPHINSTONE, of the Firm of Elliott Brothers, of
101, St. Martin's Lane, in the County of London, Electrical Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following state-
ment:-
Our apparatus is constructed for the purpose of testing firing primers to
determine the actual current required to fire them and also whether they are
in proper condition, and further for facilitating the testing of batteries to ascer-
tain if they are in a proper state of efficiency.
Two
The apparatus consists of a dead-beat ammeter movement, Figure 1 A, the
pointer B of which travels in front of the scale C, this scale can be marked off
to give actual measurement of currents and also with special marks at certain
points to facilitate the rapid testing of batteries and electric primers.
terminals G are mounted on the top of the ammeter case to which wires, leading
from the battery or primer, are attached. Permanently connected to the dead
beat ammeter movement is a contact key D. Mounted also on the top of this
casc and connected also with the key is the arm E of an adjustable rheostat, so
arranged that resistances varying from nothing up to 50 ohms. can be inserted
in the circuit. The other end of the rheostat F F is attached to one of two
other terminals G, the arrangement of connections being such that one of the
two terminals G is connected straight through to one of the two terminals G,
and the other of the terminals GI is connected through the dead-beat ammeter
movement, the contact key and rheostat to the other terminal G. The
rheostat F F consists of a wire, a part of which is wound round an insulated
rin, so that the arm, E, can touch any one of the turns of this wire. When the
whole of the wire wound upon the ring is in circuit, a further movement of the
rheostat arm causes it to make contact at any particular one of seven studs, each
connected to a small resistance coil, the pointer showing on the dial the actual
resistance which is included in the circuit at any time. A spring may be pro-
vided on the moving part of the rheostat so as to keep the whole of the resist-
ances in circuit when the instrument is left to itself. The two parts of the
apparatus are mounted in a case so as to secure portability.
The connections of the apparatus are shown in diagram on Figure 2.
The dial of the ammeter can be divided so as to read amperes direct, or when
specially required we may make special marks upon the scale so as to facilitate
the taking readings very quickly at or near these special marks. The object of
this arrangement being to test batteries as to the resistance through which they
will enable a current of a certain determined value to pass. In the case of
electric primers, where a definite current is required to fire them, this current
may have to go through a certain fixed resistance in the form of connecting
wires & so as to determine whether the battery under test is capable of performing
this, the special marks on the dial can be taken to represent any of these required
currents and then the extent of movement of the rheostat arm enables the total
resistance through which this definite current passes to be observed.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. The combination of a dead-beat ammeter with an adjustable rheostat, all
combined in a portable case substantially as described.
2. In the combination of an ammeter and an adjustable rheostat as described,
the marking of a dial with any special marks at certain points which may be
necessary to facilitate the rapid testing of batteries in connection with certain
adjusted resistance values on the rheostat.
Dated this 18th day of January 1900
ELLIOTT BROTHERS,
Agents for the said Applicants.