Abstract: The present invention relates to musical instruments and methods and apparatus for producing notes of a musical scale with real strings. More particularly, it relates to the division by frets, of the fingerboard, or neck, of a fretted stringed musical instrument, to obtain a desired musical scale with a specific set of strings. One embodiment of the invention is described in which the 12-tone equal-tempered scale is accurately produced on a guitar with steel strings having sufficient bending stiffness to cause audible intonation errors inherent in steel-stringed guitars of prior art. According to another embodiment of the invention, the musical scale is additionally tempered to approximate the 12-tone, equal-tempered scale while minimizing audible beats that occur when playing intervals and chords due to inharmonic frequency components inherent in tones generated by vibrating guitar strings. Manufacturing methods with respect to wound strings, and with respect to boundary conditions, are also explained.

Abstract: A drive system for providing ac drive power to an induction machine with asymmetrical rotor resistance and for sensorless rotor tracking of the induction machine includes: a signal injector for determining a stator command signal in a reference frame which is aligned with either an estimated rotor reference frame; a signal determiner for determining a feedback stator signal of the induction machine in a stator reference frame; and a rotor position and velocity tracker for using the feedback stator signal to estimate a rotor velocity and position by transforming the feedback stator signal into an orthogonal axis feedback stator signal in the estimated rotor reference frame, isolating a component of the orthogonal axis feedback stator signal which is in-phase with the injected stator command signals, filtering the isolated component to isolate an error term, and generating a position estimate by driving the isolated error term towards zero.

Abstract: A seismic vibrator system for imparting compressional and shear wave vibrations into the earth has an earth contacting base with a vertical post. A tubular hub is slidably received on the post in a piston/cylinder relationship. Spaced apart horizontal top and bottom plates are secured to the hub. A mass is slidably supported between the plates. Pistons interconnect the hub and the mass. Hydraulic energy is used to reciprocate the mass vertically on the post and horizontally between the plates.

Abstract: A polyphase induction machine operated by an inverter drive system. The machine is constructed with concentrated full span windings. Twelve or more phases are used to sufficiently cover the airgap region, in contrast to the conventional three phases using distributed and chorded windings. Substantial efficiency and starting torque benefits are thereby obtained.

Abstract: A simplified wiring system for an electronically controlled vending machine of the type capable of vending multiple products out of columns, trays or other queuing means, wherein by employing DC motors and various novel circuits, one may reduce controller complexity and assembly time. Selector button sensing and motor drives are connected in a matrix configuration. Sold-out switches are connected in series with the motors. Home switches are connected in series and only momentary continuity interruption is sensed. Separate sold-out switch outputs are eliminated. Interconnect wiring is reduced by mounting both the Home switch and Sold-out switch for each motor on a motor interface board permitting operation of up to 16 motors from a 10-wire ribbon cable.

Abstract: A controller for power devices which is not required to individually insulate high and low potential portions and to include an insulated power supply is disclosed. An external controller (6) is connected to a second internal control circuit (4) which is in turn connected to a level shift circuit (5) and a gate electrode of a transistor (Q2). Power supply voltage (V1) is applied to the second internal control circuit (4) for operation thereof. The level shift circuit (5) is connected to a first internal control circuit (3) which is in turn connected to a gate electrode of a transistor (Q1) and a charge pump circuit (7). Control of a first semiconductor circuit is made through the level shift means in response to an input signal generated on the basis of a second main power supply potential, thereby achieving increased responsiveness of the power devices to a control signal and improved integration.

Abstract: An electrochemical radial cell engine comprising an engine block, a motor supported by the engine block, at least one electrochemical reaction cell including a rotatable enclosure containing a source of anode material, preferably in the form of a multiplicity of anode particles, a fluid electrolyte, a cathode surrounding and radially spaced from the rotatable enclosure and means for rotating the rotatable enclosure in response to rotation of the motor. The enclosure should preferably be represented by a perforated cage having a mesh size large enough to pass fluid electrolyte. Rotation of the cage causes the anode particles to be compressed by centripetal forces which act upon the particles as the cage spins. This maximizes the operating efficiency of the electrochemical reaction cell(s) providing enhanced power for driving the engine.

Abstract: A plurality of rectangular parallelopiped tone bars are incorporated in a percussion instrument, are connected to a supporting bar at central points thereof so as to produce the second-order vertical flexural vibration and the first-order torsional vibration, and the ratio of width to thickness is regulated to a frequency ratio of 1:2 so as to improve the interval between the percussion sounds and the consonance.

Abstract: A pair of DC motors, each having a shunt-connected field winding, are interconnected such that current supplied to the shunt field winding of one of the motors is proportional to the armature current in the other of the two motors when the speed of the other motor is between predetermined maximum and minimum speeds.

Abstract: A power amplifier (18) for driving a brushless DC motor (22) includes a processor (40) which receives a signal indicative of motor situational usage and generates a mode state signal indicative of which one of a plurality of amplification modes is to be implemented in response to the received signal. The amplification modes include a linear mode and a switching mode, with the switching mode including a two quadrant switching mode and a four quadrant switching mode. The amplifier (18) further includes a controller (50) which, in response to the mode state signal, generates control signals for each of coil drive circuits (26) associated with the motor. Further, in response to a signal indicative of motor situational usage, processor (40) generates a power state signal which causes controller (50) to connect coil drive circuits (26) to a suitable one of a plurality of differing voltage sources (21, 23).

Abstract: An ink jet recording apparatus has a recording head mounted on a carrier which is shifted by a stepping motor in recording. The stepping motor is also utilized as a power source of a recovery system device. The drive mode of the stepping motor for the recovery system is differentiated from that for the recording.

Abstract: A karaoke music piece is selected through a music-piece selecting section 2, and a rhythm for the performance of the karaoke music piece is designated through a rhythm designating section 5. A performance section 6 reads a melody system track of the selected karaoke music piece, and supplies the performance data to a tone generator 8. On the other hand, a rhythm pattern producing section 7 produces a rhythm performance data for the designated rhythm based on a chord and a beat at that time, and supplies the produced data to the tone generator 8. Accordingly, the selected karaoke music piece can be played with the designated rhythm which is different from the original one.

Abstract: A variable speed AC motor control drive system for use in devices such as treadmills and including a module to sense the voltage of the line voltage provided to the system and adjusting the pulse width modulated signals provided to the AC motor in response thereto as well as providing a module for sensing the load placed on the AC motor by monitoring the bus voltage of the system and. providing a signal representative of the load such that the duty cycles of the pulse width modulated signals are varied in accordance with the line voltage of the system and the load on the AC motor to maintain the desired motor speed.

Abstract: To provide a control system for a permanent magnet synchronous motor which can ensure stability of the current control system, even if the revolution frequency of the motor becomes higher and the terminal voltage of the motor exceeds the inverter maximum output voltage. In this method, when the revolution frequency of the motor exceeds a specified value, the size of the voltage vector is made a specified voltage vector, and a modulation factor based on its value is obtained. At the same time, a magnetic flux direction current correction value is found based on the size of a voltage vector from a polarity coordinates conversion unit and the above specified voltage vector size. Then, the magnetic flux direction current instruction is corrected by that value.

Abstract: An acknowledgement-free method for the positioning of an actuator by means of an electric motor which is controlled as a function of time by a microprocessor, wherein there are proportionality constants K.sub.1, K.sub.2 of a formulaAdjustment Path=K.multidot.Adjustment Timeas well as the corresponding times T.sub.1, T.sub.2 for the braking of the rotor, after disconnection of the electric motor, from a first speed of rotation N.sub.a to a second speed of rotation N.sub.b. The constant K.sub.1 and K.sub.2 are the times T.sub.1 and T.sub.2 are determined and stored for the structural unit consisting of actuator and electric motor at at least two different loads B.sub.1, B.sub.2. Upon operation of the actuator, the time T.sub.x for the braking of the rotor from N.sub.a to N.sub.b is measured and, with the use of the stored times T.sub.1, T.sub.2, the proportionality constant K.sub.x corresponding to the time T.sub.x is calculated by linear interpolation and used for the control.

Abstract: A motor control device capable of providing an appropriate and most suitable motor current waveform, in order that efficiency and power factor for the motor is significantly improved and the high frequency and noise thereof are reduced. In an inverter type motor control circuit including a pulse width modulation waveform synthesis circuit by which a plurality of switching elements are controlled so as to obtain an A.C. power having a predetermined frequency, the pulse width modulation waveform synthesis circuit includes: memory circuit for storing a reference pulse waveform data series in order to control the switching elements; phase control circuit for controlling a starting stage of the reference pulse waveform data series which is read from the memory means; and modifying circuit for modifying and correcting a reference level of the motor control circuit so that a duty ratio of the reference pulse waveform data series is uniformly varied.

Abstract: A process for reducing the strength of an uncontrolled movement of a pointer driven by a stepper motor and abutting against a mechanical stop means when the stepper motor is switched off. Prior to the switch-off operation, the field strength of the magnetic field of the stepper motor is lowered, or the pointer is moved away from the stop means by a specified compensating angle of rotation. Alternatively, following the switch-off operation, the stepper motor is switched on again at least one time following a specified time span for a specified switch-on time span.

Abstract: An improved downhole pumping system that employs a variable speed PWM inverter and a non-gap transformer to drive an induction motor over a range of different speeds, without saturating the transformer. The variable speed PWM inverter provides a rectangular PWM signal that may be varied according to inputs from a controller to adjust the speed of the motor. The PWM inverter is electrically connected to the transformer, and the transformer is electrically attached to the motor via cables, which may be lengthy in downhole applications. The motor may be started by ramping flux producing current to a first preset value at a low frequency, then ramping torque producing current to a second preset value. If a flux measurement indicates the motor has stalled, the second preset value is increased, and the routine is restarted. Otherwise, if no stall has occurred, the motor's speed is ramped to the desired value.

Abstract: A control method is disclosed that is applicable to a washing machine having an apparatus for automatically opening/closing a washer door using a motor. The control method comprises the steps of operating the motor in a direction to transition the door between open and closed states. When a command to transition the door is entered, door motor operation is stopped if the door is successfully transitioned between states within a predetermined time interval (t1) that is started at the time of the beginning of the operation of the door motor. The door is returned to an original position (e.g., closed) if the door does not transition to a position opposite (e.g., open) the original position by the time interval (t1) elapses.

Abstract: A karaoke apparatus, a speech reproducing apparatus and a medium on which is recorded a computer program used therefor which output narration of synthesized speech including a requested song name, a requester's name or the like together with an introduction or an interlude of a song, thereby to relieve the boredom of participants during the introduction or the interlude, or the apparatus and the medium which synthesize speech of a chorus, or convert a characteristic of speech input thorough a microphone into a speech characteristic of a professional singer or the like thereby to excite participants.