is to be had which gradually raises its
voltage as the load comes on in increasing volume. Thus, one could
secure such a machine, which would begin generating at 110 volts, and
would gradually rise to 150 at full load. Yet the voltage would remain
constant at the point of use, the excess being absorbed in
transmission. A machine of this type can be made to respond to any
required rise in voltage.

As an example of how to take advantage of this very valuable fact, let
us take an instance:

Say that Farmer Jones has a transmission line 1,000 feet long strung
with No. 7 copper wire. This 2,000 feet of wire would introduce a
resistance of one ohm in the circuit. That is, every ampere of current
drawn at his house would cause the working voltage there to fall one
volt. If he drew 26 amperes, the voltage would fall, at the house, 26
volts. If his switchboard voltage was set at say 120, the voltage at
his house, at 26 amperes of load, would fall to 94 volts, which would
cause his lights to dim considerably. It would be a very
unsatisfactory transmission line, with a flat-compounded dynamo.

On the other hand, if his dynamo was over-compounded 25 per cent--that
is, if it gained 28 volts from no load to full load, the system would
be perfect. In this case, the dynamo would be operated at 110 volts
pressure at the switchboard with no load. At full load the voltmeter
would indicate 110 plus 26, or 136 volts. The one or two lights burned
at the power plant would be subject to a severe strain; but the 50 or
100 lights burned at the house and barn would burn at constant
voltage, which is very economical for lamps.

The task of over-compounding a dynamo can be done by any trained
electrician. The farmer himself, if he progresses far enough in his
study of electricity, can do it. It is necessary to remove the top or
"series" winding from the field coils. Count the number of turns of
this wire to each spool. Then procure some identical wire in town and
begin experimenting. Say you found four turns of field wire to each
spool. Now wind on five, or six, being careful to wind it in the same
direction as the coils you removed and connect it in the same way. If
this additional number of turns does not raise the voltage enough, in
actual practice, when the dynamo is running from no load to full load,
add another turn or two. With patience, the task can be done by any
careful mechanic. The danger is in not winding the coils the same way
a