Abstract: A professional audio tape transport capstan control system includes a single capstan continuously engaging a length of tape to provide bidirectional motion control in all modes of operation. A D.C. capstan drive motor is directly coupled to the capstan and energized for precise control over tape motion. A hybrid servo switches between digital position phase lock velocity control and analog constant acceleration control to provide both precise control over play speed and rapid acceleration. With acceleration to a stabilized play speed occurring in less than 0.5 sec an operator may treat the acceleration time as instantaneous for most applications.

Abstract: There is disclosed apparatus suitable for use in conjunction with film editing tables or other devices requiring precise control over shaft rotation speed, that is, apparatus for interlocking two or more shaft rotating systems to rotate one or more slave shafts in precise speed synchronism with one remote master shaft. For each slave shaft to be controlled, there is provided a differential amplifier connected in a velocity servo loop designed to force the slave shaft to rotate in precise speed synchronism with a remote or line master shaft. The primary feedback loop comprises means for generating trains of pulses having a characteristic representative of each of the rotational speeds and for deriving from these pulse trains analog voltages which are applied to a differential amplifier to produce an error signal to be driven to zero for controlling the speed of the slave shaft.

Abstract: A torque compensation system is disclosed for d.c. motor drives using field weakening for speed control. A diode switching matrix and a static divider are connected so that the divider receives signals which are functions of motor armature current and speed respectively, and delivers at its output a signal which is proportional to motor torque for adjusting the speed reference to the motor.

Abstract: An AC feedback circuit is interconnected through a choke coil between the input and output lines of a motor drive circuit so that negative feedback may be effected at a low frequency close to the cutoff frequency of the control system, and positive feedback may be effected at a high frequency. The carrier signal or the high frequency signal for controlling the switching may be generated within the drive circuit. Thus a switching type speed regulator which is simple in construction yet has high efficiency may be provided.

Abstract: A bonnet structure for generator comprising a main wall enclosing the generator and an engine for driving the generator, a partition wall for dividing the bonnet into two chambers, each chamber containing the engine and the generator, respectively, and the cover wall provided on said main wall wherein a rotor-fan of the generator is positioned within the chamber containing the engine.

Abstract: A controller for a series electric motor is described of the type comprising means for applying D.C. pulses to the motor and means for controlling the mark/space ratio of the pulses applied to the motor. The current through the motor is sensed and the maximum mark/space ratio which may be applied to the motor is reduced when the motor current is below a predetermined limit to avoid overspeed in light load conditions.

Abstract: In one embodiment, the amount of power delivered to a load depends upon the length of time a touch switch is actuated or on the number of times it is actuated. In a second embodiment, the power delivered to a load starts at one level and smoothly changes to a second level. Both embodiments include a zero-crossover detector, an a.c. operated load, and a circuit responsive both to zero-crossover pulses and to a circuit actuated by the touch switch for controlling the portion during each half period of the a.c. during which power is applied to the load.

Abstract: A gas insulated circuit breaker is provided having a plurality of circuit interrupters disposed in a single enclosure. Each interrupter is provided with its own high pressure container located within the sealed enclosure; the high pressure container also operates as an insulating support for the associated interrupter. A single actuating rod passing through the interrupters operates the contacts and blast valves of all the interrupters simultaneously. Service means are provided for the insertion and withdrawal of the interrupters into and out of the enclosure.

Abstract: An apparatus for controlling the speed of a rotary cutter driven by an electric motor for cutting to length a sheet material continuously supplied to the rotary cutter. Means are provided for applying to the electric motor a dc voltage whose amplitude is proportional to the rate of the number of pulses of a pulse train said pulse train being synchronous with the feed rate of the sheet material when the blades of the rotary cutter pass the cutting position, means for progressively decreasing the number of pulses of the pulse train, the decrease in the number of pulses beginning at a predetermined position beyond the cutting position and being effected at a rate following a first pattern, means for progressively lowering the rate of the decrease in accordance with a second pattern when the number by which the pulses are decreased reaches a first predetermined value, and means for suspending the decrease when the number by which the pulses are decreased reaches a second predetermined value.

Abstract: A servo system is disclosed for accurately regulating velocity of a rotating drum, preferably for guiding a magnetic tape of a recording and reproducing system. The method and apparatus is characterized in that generation of a ramp signal is commenced in response to a first one of a series of tach signals provided at a rate proportional to the velocity of rotation of the drum, the ramp signal being interrupted for a predetermined time duration and thereafter recommenced, the ramp signal subsequently being monitored upon occurrence of a second tach signal in order to produce an error signal for adjusting velocity of the drum motor means and maintaining the proper drum velocity.

Abstract: A control system for moving a machining member relative to a workpiece table in accordance with a set of programmed input instructions which correspond to a prescribed path of movement, including a main contour control logic to generate output signals to move the machining member relative to the table in accordance with the stored values of the components I and J of a main contour vector, a sub-contour control logic which generates output signals to move the machining member based on the stored values of the components i and j of a sub-contour vector, and cutter compensation control logic which enables either the main or the sub-contour control logic to operate based on a determination of whether the main contour vector is leading or lagging the sub-contour vector.

Abstract: A control system for a compound DC electric motor includes a shunt field winding connected in parallel with a series field winding, with both windings being connected to a power source. A time delay is positioned between the series field winding and the power source for energizing the series field winding a predetermined time period after the energization of the shunt field winding.

Abstract: A variable speed tape transport apparatus for a tape cassette wherein the tape is driven at a selected one of plural predetermined speeds. The cassette includes speed indications thereon, each indication representing a respective normal tape speed. These indications are sensed by a sensor which, in turn, controls a control circuit for the tape drive motor such that the tape is selectively driven at a normal relatively lower speed or at a normal relatively higher speed. In addition, a selector mechanism, such as a fast-forward or rewind mechanism, is provided to enable the tape to be driven at a fast speed, this fast speed being at least equal to the relatively higher normal speed.In one embodiment, a tape cassette to be driven at the relatively lower normal speed can be selectively driven at a first higher speed, equal to the relatively higher normal speed, and at a second even higher speed.

Abstract: A pulse controller for a reversible d.c. series motor is provided, in place of the conventional freewheel diode across the armature and field and plugging diode across the armature, with a unidirectional current path connected across the armature and field and containing sufficient impedance to prevent build-up of motor current in interpulse periods when the motor is in a plugging mode, and switch means for shorting out the impedance during normal motoring.

Abstract: An electrical power system is provided having two power sources, one being a commercial power source and the other being an inverter. Both power sources are connected to the load so as to share the load, approximately equally. A voltage regulator is in series with the commercial power source, and the inverter is synchronized to the commercial power source. Means are provided for failure sensing and isolation of the inverter; and means are associated with the voltage regulator which is connected in series with the commercial power source to block and sense reverse power flow in a direction from the load towards the first power source and to initiate isolation of the first power source from the load when reverse power flow is sensed.

Abstract: Disclosed herein is a direct current motor control comprising a direct current motor, a solenoid switch including an actuating coil, a first lead connecting the drive motor and the solenoid switch in series relation to each other, a second lead connected to the motor and adapted to be connected to one terminal of a direct current source, a third lead connected to the solenoid switch and adapted to be connected to the other terminal of the direct current source, a sub-circuit assembly including the solenoid actuating coil and a solenoid coil actuating switch connected in series with each other, a fourth lead connected to the sub-circuit assembly and adapted to be connected to the one terminal of the direct current source, a solenoid latching switch connected to the sub-circuit assembly in series relation thereto and also connected to the third lead, a fourth lead connected to the sub-circuit assembly in series relation thereto and in parallel relation to the solenoid latching switch and also connected to the f

Abstract: To protect a motor from overheating, its temperature is simulated at a point remote from the motor and the motor voltage is controlled to prevent overheating. The simulator comprises a cube of copper carrying a pair of heating elements: one being heated by a current proportional to motor current and the other heated by a current proportional to motor power. A temperature detector on the cube detects temperature corresponding to critical motor temperatures and is used to control motor energization.

Abstract: In order to control the peripheral speed of a rotating object, such as a grinding wheel, the current of the motor driving the grinding wheel is periodically integrated during a deceleration and an acceleration to obtain a composite signal from the integrator which reflects the necessary change in speed due to the decrease in diameter of the grinding wheel, which correction signal is combined with a signal representing a control input for a maximum size and supplied to the controller for the grinding wheel motor.

Abstract: A gas insulated circuit breaker arrangement incorporating a modular interrupter structure and having a centrally disposed single opening pull-rod and stopping means for both ends of the pull-rod stroke for controlling the movement of all of the masses of the moving parts. The acceleration spring always opposes the closing force thereby insuring that the pull-rod is in tension. Compression structure is provided to resist the tension force applied by the pull-rod and also to stabilize the interrupter structure.

Abstract: A direct current motor which includes a stator for producing a fixed magnetic field and a plurality of armature windings. The motor is caused to rotate by applying current to each winding only while that winding is passing through a zone in a given orientation relative to the stator field. The direction of rotation is changed without changing the direction of the current applied to the windings, by changing the orientation of the zone relative to the stator field, to reverse the direction of the rotational force applied to the armature. Because the current does not reverse through the armature windings, the control circuit can be simple and in a preferred embodiment includes only two gate-turn-off silicon controlled rectifiers, a switch, and a resistor.