SYNCHRONOUS INDUCTION GENERATOR 209

At non-inductive load:

ii = 0 and el = Xe02 - x^V + r4£. (10)
6] first increases, from its no-load value, eQ, reaches a maximum,
ancl then decreases again.
Since:
rt = r0 + r2 - ri,
£4 = £0 + 22 — ri,
at: r4 = 0 and x4 = 0,
or,
ri = r0 + r2,
Sl = XQ + X2,
and:
d = eo, that is, in this case the terminal vol-
tage is constant at all non-inductive loads, at constant exciter
excitation.
In general, or for /i = i — jii,
if ii is positive or inductive load, from equation (9) follows
that the terminal voltage, ei} drops with increasing load; while
if ii is negative or anti-inductive load, the terminal voltage,
e\j rises with increasing load, ultimately reaches a maximum
and then decreases- again.
From equation (9) follows, that by changing the impedances,
the amount of compounding can be varied. For instance, at
non-inductive load, or in equation (10) by increasing the re-
sistance, 7*4, the voltage, e1? increases faster with the load.
That is, the overcompounding of the machine can be increased
by inserting resistance in the rotor circuit.
124. As an example is shown, in Fig. 65, in full line, with the
total current, I = \/i2 + if, as abscissae, the voltage regulation
of such a machine, or the terminal voltage, ei, with a four-
cycle synchronous motor as exciter of a 60-eycle synchronous-
induction generator driven at 64-cycles speed.
1. For non-inductive load, or Ii = i. (Curve I.)
2. For inductive load of 80 per cent, power-factor; or
I, = J (0.8 - 0.6 j). ' (Curve II.)
3. For anti-inductive load of 80 per cent, power-factor; or
I, = j (0.8+ 0.6' j). • (Curve III.)