Abstract: A power transistor used in a chopper circuit to control field excitation of a vehicle motor when in a power mode is also used to control charging current from an a-c to d-c rectifier to the vehicle battery when in a battery charging mode. Two isolating diodes and a small high frequency filter inductor are the only elements required in the chopper circuit to reconfigure the circuit for power or charging modes of operation.

Abstract: A tachometer is coupled to the rotor of an A.C. motor and generates an output voltage proportional to the rotor's speed. A VELOCITY COMMAND voltage is generated having an amplitude which specifies a desired rotor speed. The tachometer voltage is subtracted from the VELOCITY COMMAND voltage to produce a VELOCITY ERROR voltage. The output of a D.C. power source is chopped at a fixed frequency and variable pulse width, the pulse width being proportional at any time to the amplitude of the VELOCITY ERROR voltage. The chopped D.C. voltage is filtered to provide a variable D.C. voltage having an amplitude which is proportional to the amplitude of the VELOCITY ERROR voltage. The variable D.C. voltage is applied to an inverter which changes it into an A.C. voltage. The A.C. voltage is applied to the stator windings of the motor to drive the rotor thereof. The frequency of the A.C. voltage is variable and is proportional, at rotor speeds above 150 RPM, to the amplitude of the velocity command voltage.

Abstract: This invention relates to a system for protecting an amortisseur winding during the starting of a synchronous motor. The system compares the actual slip frequency of the accelerating motor with predetermined slip frequencies. These predetermined slip frequencies are each associated with a timer which measures successive time segments. Each timer is stopped when the actual slip frequency, which decreases as rotor speed increases, is less than the associated predetermined slip frequency. When the timer is stopped a successive timer is started. In this manner the acceleration of the motor is broken up into time segments. The initial timer is started when the motor starts. The final timer is stopped when the rotor field current is applied to bring the motor into synchronism. Should any timer be permitted to have its timed segment expire before being stopped, the motor is shut down. There is also provided a thermal memory which receives information from the expired timer as to its associated slip frequency.

Abstract: Closed loop control of a pulse width modulated inverter-induction machine drive system is accomplished with a pair of microcomputers. The first microcomputer generates a periodic interrupt signal and a reference signal representative of the desired magnitude of a preselected induction machine parameter, the reference signal varying in frequency and amplitude in accordance with an externally-varied frequency value and amplitude value, respectively. The second microcomputer, when interrupted by the first microcomputer, computes the difference between the first microcomputer reference signal magnitude and the actual preselected machine parameter magnitude and the difference between the actual inverter output current magnitude and a preset limit, and controls inverter thyristor conduction accordingly.

Abstract: A battery charger system suited for use in a sterilized environment such as an operating room includes a sterilizable battery-containing pack adapted for connection to a non-sterilized battery charger through a sterilizable tray-interface. The tray-interface includes connecting structure on an upper side for mechanical and electrical connection to at least one battery pack and additional connecting structure on a lower side for mechanical and electrical connection to the charger. The upper side and lower side electrical connections are inter-connected to effect electrical coupling between the sterilized battery and the non-sterilized charger so that the battery may be charged, discharged, or tested. A sterilizable drape is adapted to be constrained between the tray-interface and the charger to isolate the charger from the sterilized environment.

Abstract: In an inverter-synchronous machine drive system wherein a synchronous machine is excited by an inverter from a source of direct current, a pair of controlled bidirectional conduction means are serially coupled across the source of direct current potential, and are coupled at their junction through a commutating capacitor to the machine neutral terminal. Each controlled bidirectional conduction means, together with corresponding phase connected thyristor within the inverter, is correspondingly gated in a predetermined sequence so as to cause alternating voltage to be applied across each corresponding machine phase for initial machine excitation.

Abstract: An aleatory source of energy, e.g., a battery of photocells (1), supplies energy to a load (5) and to a storage battery (3). When the source is supplying more energy than is being drawn by the load, the storage battery is charged; when the source is supplying less than the demand, the shortfall is made up by drawing energy from the storage battery. The state of charge of the storage battery is monitored by a meter (8) which governs a regulator (7). Once the battery is charged to a predetermined threshold, the amount of current it draws from the source is regulated, and energy supplied by the source in excess of the combined requirements of the load and of battery charging is diverted to a storage means (6) other than the storage battery (e.g., a mains electricity supply grid). The flows of energy to both the battery and the other storage means are controlled by the regulator (7) as a function of the state of charge of the battery.

Abstract: A phase-triggered, gate-controlled AC semiconductor switch of the thyrister type in series with an induction motor and its AC supply, optimizes power flow to the motor under changing mechanical load conditions by varying the amount of supply voltage applied to the motor over each half-cycle of the AC supply. The triggering point of the semiconductor switch relative to the preceding zero crossing point of the supply voltage, that is, the switch firing angle or delay angle, is varied as a function of mechanical loading on the motor by means of a load current induced feedback voltage which varies the breakdown or triggering voltage of a two-transistor switch functioning as a variable trigger diode between the gate of the semiconductor switch and a turn-on capacitor charged by the AC supply voltage during non-conducting periods of the semiconductor switch.

Abstract: A device for controlling the charging of a storage battery includes two counters (IC1, IC2) measure a minimum discharge time and a maximum charging time and are controlled by means of logic gates (2, 3) according to whether the main current is supplied or not. The device has application to maintaining a battery permanently charged despite interruptions in the mains current supply.

Abstract: A control signal for the drive of a synchronous motor is synthesized in response to direction of rotation and speed digital input signals. The synthesizer includes up-down counters for counting the speed input signal and a toggle circuit tracks the repetitive count of the counters. A digital to analog converter converts the count to an analog current. Distortion of the analog current can be provided to match the motor characteristics and to compensate for temperature variations. The distorted analog current is applied to an operational amplifier which has a non-linear feedback circuit including serially connected resistors and serially connected diodes with each resistor shunted by a diode to limit voltage drop thereacross. A multiplexer receives the output from the operational amplifier and provides the output control signal.

Abstract: A velocity change sensor adapted for mounting on a vehicle equipped with a passenger protective device, such as an inflatable air bag, comprises a body fitted with a normally open electrical switch connected to the passenger protective device's operating mechanism and adapted to be closed by a sensing mass upon movement of such sensing mass a predetermined distance in response to acceleration of the vehicle above a predetermined threshold. The sensing mass is biased to a normally inactive, initial position under a force which establishes the acceleration threshold. A biasing mass engages the sensing mass when the latter is in its initial position but moves out of engagement with the sensing mass in response to acceleration of the vehicle above the threshold level to permit movement of the sensing mass from its initial position toward its passenger protective device operating position.

Abstract: A drive for a rotating field machine which has two AC voltage integrators of identical design for forming two electric voltage signals each of which is proportional to a flux component in the machine. Each voltage integrator includes an integrator and a zero-controller having negative feedback for suppressing the DC component of input voltages fed to a summing point of the integrator. Each integrator, is fed, as one input voltage, a voltage proportional to the phase-voltage belonging to the flux component and a voltage proportional to the corresponding stator current in a machine supply lead, for compensating the ohmic stator voltage drop. A second voltage, also depending on the phase current, is processed to compensate for the inductive stator voltage drop.

Abstract: Disclosed is an AC motor drive system having a variable frequency, variable magnitude AC current supplied from a controlled inverter coupled to a variable DC current source in the form of a converter by way of a DC link including an inductor. The AC motor load is controlled so as to have dual modes of operation in order to optimize torque at any speed which can be produced within the voltage and current limitations of the variable frequency power source. The first mode comprises a constant slip or constant angle mode for operating speeds up to the corner point speed which is defined as the speed at which the motor voltage at full torque matches the maximum voltage the variable frequency inverter coupled thereto can provide. Thereafter, the system enters the second mode by automatically shifting to a constant horsepower variable slip or changing angle mode for operating speeds beyond the corner point speed.

Abstract: A separable series of secondary cells is connected across a charge circuit upon the application of supply potential. When the charge potential level upon a selected portion of the secondary cell series attains a predetermined magnitude, the selected portion is disconnected from the charge circuit. When the charge potential level upon the remainder of the secondary cell series subsequently attains a predetermined magnitude, all of the secondary cells are reconnected in series until the charge potential level upon all of the secondary cells of the series attains another higher predetermined potential level at which time the charge circuit is disabled.

Abstract: An apparatus and method for providing signals indicative of the magnitude and angular position of the DC motor flux of an AC induction motor is disclosed. The AC induction motor provides controllable rotation and torque in accordance with a drive current of variable magnitude and frequency. A first signal is provided proportional to the rate of change of the flux of the motor. A second signal is supplied proportional to the magnitude of the drive current. A flux signal is generated proportional to the integral of the first signal when the frequency of the output signal is above a preselected value and which is proportional to the second signal when the frequency of the output signal is below the preselected value. A representative value for the preselected frequency value is 3 Hertz in a 60 Hertz drive system. The flux signal is effective to control the generation of the drive current.

Abstract: An electric brake motor, particularly of the kind having a squirrel cage rotor and a slow-running stator winding with a large number of poles, is provided with electrical switching means to increase the motor current briefly on starting, at least on starting of the slowrunning winding, so as to increase the magnetic field generated by the motor current for releasing the brake. The switching means may be contacts actuated by axial movement of the rotor on starting, or a relay or contactor operated by the motor current or by a control switch. The increase in current may be achieved by briefly shortcircuiting part of the motor winding or by briefly connecting a second, fast-running stator winding in parallel with the slow-running winding in the case of a change-pole motor.

Abstract: A load-commutated inverter synchronous machine drive system control apparatus comprises at least one microcomputer for determining optimum or desired values for inverter turn-off time, inverter link current and machine air gap flux from machine drive system voltage and currents. Inverter frequency is regulated in accordance with the difference in magnitude between optimum and actual inverter turn-off time to minimize the inverter turn-off angle irrespective of machine frequency, thereby reducing synchronous machine reactive power. Inverter link current and synchronous machine field current are regulated responsive to the difference in magnitude between optimum and actual inverter link current and the difference in magnitude between optimum and actual machine air gap flux, respectively, thereby assuring machine operation at maximum efficiency.

Abstract: A back EMF controlled, synchronous, permanent magnet motor capable of extremely high rotation speeds at high efficiency. The motor includes a permanent magnet flux source and excitation coils for producing a rotating magnetic field mounted on an iron free form to substantially eliminate core loss and resulting rotor drag. Back EMF is determined directly from the excitation and controls the excitation to produce a torque angle of substantially 90.degree. between the magnet and coil fluxes. Coil excitation is used at maximum efficiency and hunting is avoided. The permanent magnet provides a high flux density that also allows a low current in the motor coils and thus reduces coil copper losses to further improve efficiency.

Abstract: A mooring winch system in which automatic mooring duty is performed by a winch having an AC motor fed from the supply via a converter which includes a DC to AC inverter, the convertor producing a balanced three-phase square, quasi-square, sinusoidal or quasi-sinusoidal output. The motor thus can stall indefinitely, be driven in the sense of rope payout by tension force in the mooring rope, or run in the opposite sense to recover rope, without exceeding its rated temperature for that duty. Rope recovery is adequate both for normal duties and also where higher speeds of recovery are required and rope tension is maintained substantially constant throughout.

Abstract: A coreless three-phase DC motor comprising a coil type armature formed with insulated windings. The armature is of a disc- or cylindrical-shape and is set rotatably against a field magnet provided with 2n magnetic poles N and S magnetized in equal angular widths. On the surface of the armature there are 3n/2 three-phase armature coils, wherein the angular width of each of the coils is equal to the width of the field magnet pole, the coils of each phase are shifted by 180.degree. of electrical angle from each other, and all the armature coils are arranged at equal angular intervals and not superimposedly with respect to one another.