The Virginia enterprise. [volume] (Virginia, St. Louis County, Minn.) 1893-19??, 1897-02-12

an men 1uftnef toward the end OF the
shaft. another layer Of cotton and copper
that no Wire was bound under it. These
two bands of copper are known as ''conl
mutators,' the bound wire being fas-
tened to the further band and the un-
bound wire to the end nearest the core
Next came the frame. 1t was made
of four pieces of wood, the base being
six inches long. a half an inch wide
and two inches high. The top piece
was an inch longer than the base, and
threc-quarte:rs of an inch wide. The
two end pieces were six inches long.
three-quarters Of an inch wide, and
half an inch thick. They were all
screwed solidly together, so as to make
a strong frame. John had to be care
full to get the cnd surface of each piece
Of wood perfectly true and square.
otherwise the frame, as Il whole, must
have been distorted and tout of plumb"
In each of the end pieces a hole was
made large enough to allow the shaft
to pass through. These holes were to
serve as bearings and the armature had
to be placed i'll position before the sec
screwed on. The appearance of the
whole at this stage of construction is
shown in figure 3.
The next thing was the construction
of what are known as the ''felds."
First, the two plates of iron were bent
in the manner shown in the cut, leay-
ing two and a quarter inches fiat at
one end-the 1owcr-and one and
quarter at the upper. Next the lower
flat surface of each plate was insulated
by wrapping it with paper to within
one-quarter of an inch Of the bend
Then four layers of the No. IS copper
wire were evenly wound over the paner,
both ends of the wire, i'll each case, be-
ing brought to the same end of the iron
plate. Next the upper ends of the two
plates were screwed fast to the ton
piece Of the frame, this caused the
plates to assume an upright position.
with the wound end of each resting
against the base piece, and these were
held firmly in place by strip of tin
screwed to the wood of the end pieces
should be made perfectly clear by the
cut.
When the work had progressed thus
far, John found that the arlnaturc was
lying III such way that it could be
easily revolved i'll a space between the
concave surfaces of the fields, though it
nearly touched them, and that nothing re-
manned to be done excepting to provide a
way for the current to pass between the
electro magnet of a dynamo-and through
the armature, (which then" Johns
friend explained will begin to whirl at
practically the same rate of speed as the
dynamo
Two strips of sheet copper, each two
inches long by a quarter of an inch wide,
were then cut. In each of these strips
John had made an IL bend about a
quarter of an inch from one end. Through
the short end he bored a hole, and
through this he screwed the strips fast
to the base Of the frame, III such a way
as to bring the long ends in contact with
by the cut. The screw which fastened
the copper strip-or brush the
end was allowed to project about Il quar-
ter OF al inch, and was to be used as one
Of the binding, posts or point of connec-
ton from the dynamo. About a quarter
OF all inch from this scrcw-or binding
and allowed it also to project about a
quarter of an inch. This was to serve
as the other binding post or point of
connection with the dynamo.
From the coil around the lower part of
each piece of iron forming the "fields,"
it will he remembered, there extended
two free wire ends, or four altogether
One wire from each coil was now con-
nected with the other; the remaining free
end from one coil being connected with
the strip of copper-or brush-nearest
the feld-not the binding post-whle the
one from the other coil was connected
with the projecting screw or binding post
that had been driven into the wood This
is marked "a" in the cut: the other bind
ing post-the screw holding one of the
brushes in place-being marked "B," and
it is to these two binding posts that the
wires from the dynamo were connected.
Then a wooden pulley, or driving
wheel, with groove for round belt,
was attached to the end Of the armu-
ture shaft projecting from the frame,
and the electric current was turned on.
1t passed in through the binding post
marked "A;' traversed the fields; then
through one brush to the arnlature by
way Of the corresponding commutator;
passing from the armature to the other
commutator; to it's brush and off through
the binding post marked "B," through
the return wire of the circuit and on
back to the dynamo. Instantly the arna-
ture began to whirl and the motor was
complete. '..%.
"Now," said Johns friend, eff you
were to apply power to the motor in 1
stead of to the dynamo a current would
be generated by the motor and the dy-
nalnO. could be operated as n motor.
In other words Il dynamo may be used
as 2 moor and motor may be used us
q dynamo They are interchangeable,
the same as the two wheels III the circ,,.
" 80