CONTENTS xiii
PAGE
86. Relation of motor torque curve to voltage regulation of system
—Regulation coefficient of system—Stability coefficient of
system........................138
87. Effect of momentum on the stability of the motor—Regulation
of overload capacity—Gradual approach to instability . . . . 141
CHAPTER VII. HIGHEE HARMONICS IN INDUCTION MOTORS.
88. Component torque curves due to the higher harmonics of the
impressed voltage wave, in a quarter-phase induction motor;
their synchronous speed and their direction, and the resultant
torque curve......................144
89. The component torque curves due to the higher harmonics of
the impressed voltage wave, in a three-phase induction motor—
True three-phase and six-phase winding—Tie single-phase
torque curve of the third harmonic...........147
90. Component torque curves of normal frequency, but higher
number of poles, due to the harmonics of the space distribu-
tion of the winding in the air-gap of a quarter-phase motor—
Their direction and synchronous speeds..........150
91. The same in a three-phase motor—Discussion of the torque
components due to the time harmonics of higher frequency
and normal number of poles, and the space harmonics of normal
frequency and higher number of poles...........154
92. Calculation of the coefficients of the trigonometric series repre-
senting the space distribution of quarter-phase, six-phase and
three-phase, full pitch and fractional pitch windings.....155
93. Calculation of numerical values for 0, Y§, Y^ M pitch defi-
ciency, up to the 21st harmonic.............157
CHAPTER VII. SYNCHRONIZING INDUCTION MOTORS.
94. Synchronizing induction motors when using common secondary
resistance.......................159
95. Equation of motor torque, total torque and synchronizing
torque of two induction motors with common secondary rheo-
stat .........................160
96. Discussion of equations—Stable and unstable position—Maxi-
mum synchronizing power at 45° phase angle—Numerical
instance........................163
CHAPTER IX. SYNCHRONOUS INDUCTION MOTOR.
97. Tendency to drop into synchronism, of single circuit induction
motor secondary—-Motor or generator action at synchronism—
Motor acting as periodically varying reactance, that is, as
reaction machine—Low power factor—Pulsating torque below
synchronism, due to induction motor and reaction machine
torque superposition..................166