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CONTENTS

PAQB

74. Calculations of voltages, torque, torque ratio and efficiency . . 114

75. Numerical instance of shading coil of low, medium and high,
resistances, with motors of low, medium and high armature
resistance.......................116

76. Monocyclic starting device—Applied to three-phase motor—
Equations of voltages, currents, torque, and torque efficiency . 117

77. Instance of resistance inductance starting device, of condenser
motor, and of production of balanced three-phase triangle by
capacity and inductance................120

78. Numerical instance of motor with low resistance, and with
high resistance armature—Discussion of acceleration .... 121

CHAPTER VI. INDUCTION MOTOR REGULATION AND STABILITY.
1. Voltage Regulation and Output
79. Effect of the voltage drop in the line and transformer im-
pedance on the motor—Calculation of motor curves as affected
by line impedance, at low, medium and high line impedance . 123
80. Load curves and speed curves—Decrease of maximum torque
and of power factor by line impedance—Increase of exciting
current and decrease of starting torque—Increase of resistance
required for maximum starting torque...........126
2. Frequency Pulsation
81. Effect of frequency pulsation—Slight decrease of maximum
torque—Great increase of current at light load.......131
3. Load and Stability
82. The two motor speed at constant torque load—One unstable
and one stable point—Instability of motor, on constant torque
load, below maximum torque point............132
83. Stability .at all speeds, at load requiring torque proportional to
square of speed: ship propeller, centrifugal pump—Three
speeds at load requiring torque proportional to speed—Two
stable and one unstable speed—The two stable and one un-
stable branch of the speed curve on torque proportional to
speed.........................134
84. Motor stability function of the character of the load—General
conditions of stability and instability —Single-phase motor . . 136
4. Generator Regulation and Stability
85. Effect of the speed of generator regulation on maximum output
of induction motor, at constant voltage—Stability coefficient
of motor—Instance...................137