190

ELECTRICAL APPARATUS

Substituting thus different values for the secondary external
impedance, Z, gives the regulation curve of the frequency
converter.

Such a curve, taken from tests of a 200-kw. frequency converter
changing from 6300 volts, 25 cycles, three-phase, to 2500 volts,
62.5 cycles, quarter-phase, is given in Fig. 63.

PRK
1ARY

.......

n i

- ........

VOLTS
.6500. 6000.
AMP.
__13_ ™12-UU

/

/

A
/

/

9

x

8

LX

7-

/
'

— --
*^
^

COMPOUNDING CURVES SECONDARY, 2500 VOLTS CONSTAN1 62.5 CYCLES QUARTER-PHASE PRIMARY, 25 CYCLES THREE-PHASE

__ 5-4

0
]
0

SE
0
fONDAF s
!Y CUR
to
3ENT f 4
>ER PH 0
\SE, A
V
6
D

FIG. e^.-^-Compounding curve of frequency converter.
Prom the secondary terminal voltage:

it follows, absolute:

ei = e V6i2 + &22, e =

Substituting these values in the above equation gives the
quantities as functions of the secondary terminal voltage, that
is, at constant, 61, or the compounding curve.
The compounding curve of the frequency converter above
mentioned is given in Fig. 64.
110. When running above synchronism: s < 0, the general
alternating-current transformer consumes mechanical power and