Abstract: A security timer for a powered overhead garage door causes the garage door to close after it has been opened for a selected time interval. The security timer includes an oscillator that provides pulses. A counter counts the pulses and provides a binary output. A timer switch is engaged by the door when the door is fully open. Engagement of the timer switch signals the oscillator and counter to begin. When the desired number of pulses has been counted, a relay switch is closed for signaling the operator unit of the door to close the door.
Abstract: This disclosure relates to a circuit for controlling energization of a start winding of a single-phase motor connectable by power lines to an AC power supply. The circuit includes at least two triacs connected in back-to-back series relation and connected in series with the start winding. The circuit further comprises a reed switch including reed contacts and a reed coil. The gates of the two triacs are connected across the reed contacts, and the reed coil is connected in one of the power lines and receives the line current during energization of the motor.
Abstract: A head phone is disclosed, which includes a pair of housings, each holding therein an electro-acoustic transducer, a head band being extendable and shrinkable, a pair of supporting members, each being curved in substantially inverse L-shape with each other and supporting at its one end one of the pair of housings, and a pair of pivotally supporting members, each being fixed with one of both ends of the head band and pivotally supporting the other end of one of the pair of supporting members in such a manner that each of the supporting members is rotatable around its lengthwise direction and also rotatable against the extending direction of the head band.
Abstract: Apparatus for controlling wheel slip in a locomotive driven by d.c. motors which receive power from a diesel driven generator, has sensors which provide signals representing speeds of different driven wheels to a velocity unit. The velocity unit derives a differential signal representing the difference between the highest and the lowest wheel speeds. A sensor detects current or power in the generator output and the signal from this sensor is sampled periodically and the latest two sampled values are stored. The sampled values are compared to provide a creep reference signal. The differential signal and the creep reference signal are compared and the resulting difference signal is used to control generator output to maximize current during acceleration.
Abstract: An automatic radio telephone encoder/decoder including a microcomputer programmed to decode incoming dial codes and generate outgoing radio telephone functions and dial codes in response to received signals or keypad activation is presented in combination with control circuitry activated by the microcomputer which is maintained in an off condition except when called upon to perform encoding or decoding functions by a keyboard input means or signals received by the radio telephone.
April 1, 1981
Date of Patent:
July 31, 1984
Midian Electronics, Inc.
Charles Soulliard, Herschel W. Ward, Arthur D. Gass, Andrew M. Hudor, Jr.
Abstract: A single phase alternating current electric motor is provided with a main stator winding having two coil groups which are connected to form eight poles for eight-pole operation and to form six poles for six-pole operation. Each group contains four series connected coil elements with each element spanning approximately one-seventh of the periphery of the machine. The coil groups are spaced 180 mechanical degrees apart such that each end coil of one group overlaps one of the end coils of the other group. An auxiliary stator winding having two coil groups with the same relative angular displacement as the main stator winding coil groups is included.
Abstract: A variable speed 3-phase a-c motor is connected to a 3-phase source of alternating voltage via five controllable bidirectional solid state switches which are so arranged and controlled that motor speed can be reduced by skipping selected cycles of the source voltage. For example, for half speed operation three of the switches are arranged respectively to connect phases A, B and C of the source to phases A, C and B of the motor, and over two consecutive periods of the source voltage three separate, uniformly spaced "firing windows" are selected during which the conducting states of these switches are initiated in a predetermined pattern that results in the phase A-to-phase B source voltage being applied to the motor during the first window, the phase C-to-phase A source voltage being applied during the next window, and the phase B-to-phase C source voltage being applied during the last window.
Abstract: A speaker system which comprises two speakers and a switch for selectively connecting one of the speakers to an input through a volume controller. The other of the speakers is always connected to the input, so that in response to switching action of the switch, two speakers may operate as twin-drive woofers or the former one of the speakers may operate as a passive radiator. The volume controller is used for attenuation adjustment of the twin-drive woofers and damping adjustment of the passive radiator.
Abstract: A handset for a telephone set is provided with a receive amplifier which is compatible with both electronic and electro-mechanical telephones, that is telephones having electro-mechanical transmitters and telephones having electronic transmitters. The operational amplifier is powered from the telephone line, from the power input to the telephone network, and is driven via an impedance matching circuit exhibiting a low AC impedance and having a capacitor to short out AC signals such as voice signals on the telephone line and a special transistor which has high AC impedance and low DC resistance to block out AC signals and provide DC power. The operational amplifier is of special characteristics, stabilized to work down to very low voltages, e.g. 1.1 volts and also capable of operating at higher voltages, e.g. 20 volts.
Abstract: This invention concerns a method of controlling mill-motor speed in a cold tandem mill. During unsteady phases of rolling operation such as threading, rolling speed acceleration and/or deceleration, and tail out with respect to the coil being rolled, mill motors are so controlled as not to perform drooping characteristic action except under certain specific conditions, and at threading phase in particular, motors in individual stands are so controlled as to revolve at a uniformly decreased speed, whereby final gauge control accuracy can be improved with respect to top and bottom end portions of the coil and such troubles as coil cut and the like can be effectively prevented.
Abstract: To permit operation of an anti-skid or anti brake-lock system with wheels having dual braking cylinders, controlled by separate braking valves, control signals to control separate brake valves (V.sub.11, V.sub.12) at respective sides of the vehicle are derived for a first braking system (I) in accordance with well known technology, based on wheel acceleration, deceleration and the like, processed in an anti-skid control unit (9), and a second braking system, controlled by a single valve (V.sub.2), is provided connected to the second braking cylinders in both wheels. The control signals for the second valve (V.sub.
Abstract: An apparatus and method for increasing the maximum speed of rotation of a synchronous machine having constant excitation field strength is disclosed. The synchronous machine is preceded by a converter, which has an adjusted current reference value as an input. The adjusted current reference value comprises an active-current reference value and a reactive-current reference value. For actual speeds n.sub.ist, the absolute value .vertline.n.sub.ist .vertline. of which is above a predetermined value n.sub.o, the amplitude of the active-current reference value is limited to a value which is inversely proportional to the factor .vertline.n.sub.ist .vertline./n.sub.o. The value n.sub.o is a predetermined speed at which the sum of the magnet wheel voltage of the synchronous machine and the voltage drop in the stator winding is maximally equal to the largest possible output voltage of the converter. To obtain the adjusted current reference value, a reactive-current reference value shifted 90.degree.
January 14, 1983
Date of Patent:
July 17, 1984
Gunter Schwesig, Hartmut Vogt, Erich Voss, Hans-Hermann Zander
Abstract: A driving circuit for a two-phase brushless motor includes a servo control device operating to make constant the phase difference between a sum signal indicative of the current sum flowing through the motor coils and a positional signal indicative of the relative position of the motor rotor and the coils.
Abstract: A crime prevention apparatus for controlling the operation of an elevator which comprises a night detector for detecting night, a passenger detector for detecting the presence of only one adult passenger in an elevator cage and a start instructing unit for enabling the operation of the cage only when the passenger and the night detectors are operated, thereby allowing the operation of the cage only when one adult passenger rides in the cage during the night and thereby preventing most crimes from occuring in the cage during the night.
Abstract: The motor assembly comprises a bidirectional stepping motor having a coil, a stator provided with a central opening in which is mounted for rotation about an axis a rotor including a permanent magnet which is magnetized along an axis of magnetization, and positioning means for defining two rest positions of the rotor in which the axis of magnetization of the magnet is directed along an axis of static equilibrium. The stator is formed of two pole pieces which partly surround the rotor and are interconnected by two intermediate parts and by four isthmuses in such a manner that the intermediate parts are intersected by the axis of static equilibrium and that two isthmuses which are opposite each other in relation to the axis of rotation of the rotor are located in one direction making with the axis of static equilibrium an angle of between 30.degree. and 60.degree..
Abstract: A device is attached to the compensating rope sheave assembly in an elevator system to detect rope sway exceeding a certain magnitude. The device includes a switch which is attached to the assembly and a loop which is positioned around the rope. The loop is attached to a movable member of the switch. When the rope sways and contacts the loop, it actuates the switch. The loop can be opened to place it around the rope, and it is made of pliant material to protect the switch and the rope.
Abstract: An adjustable speed machine-commutated inverter-synchronous motor drive includes control of the inverter at a selected rate without positioning. The line converter is controlled so as to maintain a relation I=f(T) and the relation E/l=g(T) is established by applying to the field regulator loop a reference which is a function of T, where T is the torque, I the current drawn by the motor drive and E the excitation voltage. Accordingly, the torque is not sensed. The functions are chosen so that the commutation margin angle is safe under natural commutation by the EMF of the motor and also chosen to improve drive operation.
Abstract: An anti-skid vehicle brake control system having a sensor for monitoring and producing electrical signals corresponding to the speed of a vehicle wheel. The electrical speed signals are processed by a first microcomputer circuit for forming data words. The data words are fed to a filter network which includes a parallel-connected exponential, linear, and percentile filter section for suppressing interference pulses. The filtered data words are fed to a second microcomputer circuit which produces control signals. The control signals are fed to a solenoid valve which controls a brake cylinder on the vehicle.
Abstract: An elevator group supervisory control system for allocating elevator hall calls to elevator cars depending upon estimates given by processing of data indicative of travels of said cars, including a probability processor for determining an estimated future response probability based on predetermined travel data and an estimation processor for allocating hall calls to respective elevator cars based at least in part on the estimated future response probability.
Abstract: A phase-detector (16, 18, 20) is provided for use in a power factor controller for a three-phase induction motor. The power factor controller includes switching thyristors (10, 12 14) for each motor phase winding and the phase detector for each phase includes an operational amplifier (36) which senses the current phase angle for that phase by sensing the voltage across the phase thyristor. Common mode rejection is achieved by providing positive feedback between the input and output of the voltage sensing operational amplifier.
December 16, 1982
Date of Patent:
July 10, 1984
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration