Abstract: An inertial measuring unit gyroscope wheel dynamic braking and sequence inhibiting circuit is disclosed. The circuit comprises a first counter for counting a specified time interval and digital logic circuitry for applying an in-phase signal to the phases of a multiphase electric induction motor driving a gyroscope wheel during the time interval, for example, a vertical gyroscope motor wheel. By placing in-phase signals on the inputs of a multiphase electric induction motor, the motor is brought completely to rest in a short time by dynamic braking. In a preferred embodiment, a second counter counts a second specified time interval after the first time interval has terminated, during which second time interval a second electric induction motor is dynamically braked, for example, an azimuth gyroscope wheel motor. During the time period when the motors are braking, a signal is fed back to an automatic sequencing circuit to inhibit further sequencing of the inertial measuring unit.

Abstract: A drive equipment has an AC motor and a self-commutated static converter for transmitting electrical power between the motor and a network for driving and braking the motor. The equipment has braking resistors, each of which is connected between a DC terminal and an AC terminal of the converter. Connected in series with each braking resistor is a thyristor which acts to control the current through the braking resistor.

Abstract: Emergency braking device for a brushless motor comprising damping means connected through a switch to the windings of the brushless motor in case of emergency to dissipate the energy stored in the inductance of the windings of the brushless motor. The impedance characteristics of the damper means are optimized by selecting a capacitance which has a predetermined relationship to the inductance of the motor winding.

Abstract: A squirrel cage motor comprises a stator and a rotor, the latter having a pair of end rings and conductor bars interconnecting the end rings, the bars and rings being supported on the rotor core. At least one end ring is provided with at least two insulating gaps to divide that end ring into at least two separate portions. The rotor of the motor can be braked to stop at a predetermined position by applying to the secondary winding of the stator D.C., or A.C. of the same phase as that applied to the primary winding. A three-phase motor can similarly be arranged by providing at least three gaps in at least one end ring.

Abstract: The motor braking circuit for use with an alternating current motor and an AC power source includes a power circuit for supplying a DC braking current to the AC motor and a motor speed sensor which causes a mechanical brake to engage the AC motor and its load when the motor speed decreases to a predetermined value. The DC braking current is applied to start the electrical braking cycle as soon as the AC source is disconnected from the AC motor. The RPM sensor monitors the speed of the AC motor during the electronic braking cycle and causes the mechanical brake to engage the motor and its load when the motor speed decreases to a predetermined value to complete the stopping sequence. The AC motor braking system can be installed without any additional direct wiring or additional hardware to the AC motor.

Abstract: A reciprocating drive system moves a body of defined inertia, such as a carriage supporting electrostatic spraying means, at full speed between two points at which the direction of movement is reversed. The drive system includes an electric motor with polyphase stator windings and a squirrel cage rotor. Transducers responsive to the arrival of the moving body at the aforementioned points produce output signals controlling a phase switching system which reverses the direction of rotation of the motor. Reversal of the motor torque reverses the direction of movement of the moving body within a given travel and within a given time interval to full speed in the opposite direction. A stator current limiter provides positive coupling in an operative condition and no coupling in an inoperative condition with the motor running at full speed. The motor is selected so that the inertia of its rotor closely matches that of the moving body.

Abstract: A three-phase electric motor is partially braked as a result of self-excitation when the power supply is disconnected and a capacitor is connected across one of the windings. The motor is then rapidly brought to a standstill by applying a short-circuit (or connecting a relatively low impedance) across one or both of the other windings, and essential condition being that the short-circuit is initiated within a predetermined range of values of phase angle in a waveform of the self-excitation. Preferred ranges of phase angle are established for selected configurations of mechanical and electronic short-circuiting switches.

Abstract: The motor braking system for use with an alternating current motor and an AC power source includes a power circuit for supplying a DC braking current to the motor. A capacitor which was charged during motor operation, discharges when the motor is turned off and thus provides a pulse of energizing current to a contactor which quickly connects the power circuit to the motor and starts the electric braking cycle as soon as the AC source is disconnected from the motor. A timing circuit is also started and maintains the energizing current for a predetermined amount of time while the motor is coming to a stop. A mechanical brake may also be used to complete the stopping sequence if desired, with the mechanical brake being engaged when the braking current is terminated.

Abstract: A controlled current inverter motor control system including a controlled source of direct current for supplying a variable frequency inverter by way of a direct current link circuit which includes, within the link circuit, a selectively insertable dynamic braking resistive element. Upon a call for a dynamic braking mode of operation, the source of direct current is short circuited and the normal operational or running control of the motor is discontinued. Special circuitry is provided which then forces a special frequency control of the inverter to thus control the angle between the motor flux and motor current to a prescribed value proportional to the extant value of a motor operating parameter (motor current or motor flux) prior to the insertion of the dynamic braking resistive element into the link circuit.

Abstract: An improved capacitive braking system is provided for fractional Horsepower induction motors in home appliances, for example in a food processor of the type having a working bowl mounted on a housing containing the induction motor, with a shaft in the bowl for removably supporting a rotary food processing tool to be driven by the induction motor. The new braking system rapidly halts the coasting motion of the motor rotor and tool after the motor has been disconnected from the electric power line. A first switch is provided to control the application of electrical energy to the induction motor for sustained operation, and a second "pulse" switch is provided to control the application of electrical energy to the induction motor for brief surges of momentary operation. The braking system includes a second capacitor which is external to the induction motor and distinct from the starting capacitor normally associated with an induction motor.

Abstract: A controlled current inverter system forms the basis of an a.c. motor drive system for furnishing the motor load with a variable frequency, variable magnitude a.c. current from an inverter which is supplied from a variable d.c. current source by way of a d.c. link including an inductor. Torque is the control parameter employed in the system and the motor speed and torque are controlled through the control of motor flux and motor current, by maintaining a controlled ratio between the direct and quadrature motor currents, through separate control paths to the d.c. source and the inverter. A third control path functioning on the difference between the desired and actual motor flux serves as a modifier to the main control paths to improve overall operation and control. Means associated with the basic control paths provide for dynamic braking of the motor.

Abstract: An electrically braked alternating current motor includes a first, or primary, brake winding that is normally energizable to brake the motor and at least a second, or backup, brake winding that is alternatively energizable with the first brake winding to electrically brake the motor if the first brake winding fails.