Abstract: Disclosed herein is an electromechanical actuator which acts as an analog of a fluid operated cylinder. A tubular piston moves along the axis of a fixed outer cylinder. One end of the piston is fitted with a threaded stud to which a clevis or other load attachment device can be attached. The other end of the piston, inside the outer cylinder, is attached to a coaxial drive nut. The drive nut is threaded onto a coaxial lead screw which passes through the drive nut and clears the inside of the piston. The drive nut is notched at a plurality of locations, the notches corresponding to a plurality of axially extending protrusions on the inside of the outer cylinder. Thus, when the lead screw is rotated, translational motion is imparted to the drive nut due to its inability to rotate relative to the outer cylinder. A small bar magnet is affixed to the drive nut and cooperates with an external reed switch to provide intermediate shutoff points.

Abstract: A circuit for a polyphase motor which operates in response to undesirable operating conditions so as to prevent damage to the electric motor. The protection circuit converts current to voltage over a range of operating currents. The current sensitive voltage in response to an undesired current condition triggers the operation of a gating circuit to apply potential to an output switch which in turn controls the current supply and stops the motor. The gating circuit is also triggered by a detector circuit sensing a deficiency in motor current to thereby actuate the output switch and interrupt the motor operation and thus protect the motor. A timing circuit provides an inverse time function in conjunction with the voltage applied to the gating circuit. The timing circuit is adjustable to provide adjustability in the elapsed time for providing a triggering voltage to the gating circuit.

Abstract: A device is described for converting solar energy into electric power for a load, which device is provided with photocells and electric accumulators. Switching means are provided which at least during starting of the load connect this load to the output terminals of the array of photocells so that during starting the current through the load is determined by the current supplied by the photocells. The device makes efficient use of the available solar radiation, is of simple design and is reliable.

Abstract: Electronic control means for a paper handling and counting machine. An LED array provides a visual display of the number of paper documents counted during either normal counting or "batching" operations. The LED display is utilized to the exclusion of additional display devices for providing an indication of a jam condition in the event of a jam by "flashing" the zero decimal digit. A similar indication is artificially created upon turn-on of the machine. When operating in the "batching" mode the LED array, in addition to providing a visual display of a completed batch count, will display a partially completed batch count in a flashing manner. The "jam-type" display is also activated whenever the batch control selector switch is switched from the "count" mode position to any batching mode position.

Abstract: A controller for a motor or like electrical equipment. A thyristor in series with a power conductor that feeds the equipment and a control circuit for activating the gate terminal of the thyristor in accordance with the operating conditions of the equipment. The control circuit includes a transformer having a secondary winding connected to the gate terminal and means for varying the current flow in the secondary winding according to load demands. A three phase system having a thyristor in each conductor and a transformer secondary winding for each thyristor, which windings are on a common core.

Abstract: The load currents, supplied by a three-phase AC power source to a three-phase load, are established and maintained at a preset desired level by sensing those currents and producing a feedback voltage which is compared with a reference potential. Anytime the load currents differ from the desired level the comparison produces a difference or error signal which causes an adjustment of the amplitudes of the three load currents such that they automatically return to the desired level, thereby regulating the current flow to the load. At start-up, the feedback arrangement is also effective in preventing instant current build-up to avoid sudden power surges. When the load is a three-phase motor, limiting the current flow facilitates a soft start with the motor gradually accelerating to full operating speed. Two overload protection circuits shut the system down in response to different overload or overcurrent conditions.

Abstract: A solid state relay structure for use with different alternating current motors having a range of full load current and service factor ratings. The relay includes a rectangular housing and bores extending through the housing through which conductors to the motor are passed. The rear end of the housing is spaced from the panel on which the relay is mounted so the conductors may be looped through the bores when portions of the looped conductors are passed in the space between the rear end of the relay and the panel. The solid state components of the relay are encapsulated in the interior of the housing and are connected to switches, terminals, and a light emitting diode located at the front of the housing so the relay may be easily programmed for use with motors having different ratings. The terminals and operating and test instructions, located at the front end of the relay, provide a convenient arrangement for wiring the relay in its control circuit and information to program the relay.

Abstract: A manually-controlled, pneumatically-actuated electric motor starter and overload protection system wherein actuation and automatic overload protection are accomplished wholly pneumatically without any electromagnetic actuating circuitry so as to render the system more reliable and shockproof regardless of age or deterioration.

Abstract: A cut-off switch is provided between the motor driving a sliding panel and the power supply for the motor. The cut-off switch becomes operative when the torque supplied by the motor during the displacement of the panel between the open and closed positions of the panel exceeds a predetermined value. An inhibiting device inhibits the actuation of the cut-off switch when the panel is in the immediate vicinity of its closed position.

Abstract: A self-powered solid state overload relay circuit having current transformers energized by conductors supplying current to a multiphase alternating current motor. The transformers have secondary windings connected to charge a capacitor with a voltage indicative of the magnitude of the maximum current in the motor windings. The circuit includes presetable impedance circuits which permit the circuit to be easily programmed to respond to a range of abnormal motor currents in the winding in motors of varying size and service factor ratings, components which are arranged to duplicate the operation of melting alloy and bimetal type overload relays in an automatic or in a trip-free manual reset mode, a light emitting device which visually indicates when the relay is in a tripped state, and components which cause the relay to be insensitive to ambient temperature variations.

Abstract: An over-speed preventing apparatus for the DC motor comprises a DC motor the speed of which is controlled by the adjustment of the armature voltage thereof, controlled-rectifier means for supplying power to the separately excited field winding of the motor, means for generating a predetermined field current command, means for detecting the field current, and a constant current control system for controlling the rectifier means in accordance with the error between the field current command and the detected value of the field current. The apparatus further comprises a unidirectional element connected in parallel to the field winding in the direction in which the field current is made to flow back, current decrease detector means inserted between the rectifier circuit and the parallel circuit including the field winding and the unidirectional element, and protecting means energized by the current decrease detector means.

Abstract: Negative sequence compensation apparatus for reducing, and thereafter minimizing the increase of, negative sequence currents flowing in a three phase motor includes variable impedance elements, and means for adjusting the impedance thereof, disposed in the motor supply lines. Alternate embodiments disclose saturable reactors as the variable impedance elements electrically connected with the supply terminals by way of alternate transformer connections.

Abstract: Motor protector apparatus for independently sensing the respective positive, negative, and zero sequence currents flowing in the supply lines to a three phase motor for interrupting power to the motor whenever such positive, negative, or zero sequence components reach levels indicative of abnormal operating conditions. The protector network includes bridge means for segregating the negative and positive sequence components, indicators for visually displaying the source of the abnormality, and means for restoring power to the motor after a defined time period.

Abstract: A protection system for an electric motor including a safety switch to deenergize the motor upon the occurrence of a potentially deleterious operating condition. The protection system includes a current sensitive device in series with the motor. The device is deenergized when the motor is deenergized due to the occurrence of the deleterious operating condition. The protection system further includes a holding device having a normally closed switch electrically connected thereto. The holding device is energized and its switch is opened when the current sensitive device is energized. The holding device remains energized, even though the current device is deenergized, to prevent the motor from being reenergized. The holding device is deenergized to permit reenergization of the motor by the manual opening of a switch connected in series therewith.

Abstract: Complete protection of a three-phase submersible pump motor, such as the type used downhole in an oil well, is obtained with a solid state digital logic control system that monitors each of the three phase currents and shuts the pump motor down if any of those phase currents indicates either an underload or overload condition. Time delays are introduced before shutdown to avoid undesired nuisance shutdowns otherwise caused by transient or momentary conditions. When the pump motor is de-energized in response to an underload condition, it is automatically restarted after a predetermined time delay. All of the delay functions are precisely determined by division of the power line frequency. Downhole pressure and temperature are also sensed and if they become excessive the motor is automatically de-energized to prevent overheating. The presence of an auxiliary physical condition, such as filling up a retaining tank, also causes the pump motor to be turned off.