CONSTANT SPEED CONTROLLING DEVICE FOR A DIRECT CURRENT MOTOR

• US 3,783,357 A
• Filed: 11/10/1971
• Issued: 01/01/1974
• Est. Priority Date: 11/14/1970
• Status: Expired due to Term

• Current Assignee: Toshikazu Ichiyanage
• Original Assignee: Toshikazu Ichiyanage
• Inventors: Ichiyanage, Toshikazu
• Primary Examiner(s): Rubinson, Gene Z.
• Application Number:
  US05/197,255
• Time in Patent Office: 783 Days
• Field of Search: 318/138,171,254,227,230,231,341,685
• US Class Current: 318/400.09
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02P 6/21 Open loop start

Abstract

An improved DC motor is provided with an external reference (frequency signal) oscillator, means for detecting the angular position of a rotor of the motor including magnets, and control means which is adapted to flow the exciting current to the field or driving windings of the motor in synchronism with either the output signals from said reference oscillator and said detecting means, and to interrupt the exciting or driving current in response to the other signal, whereby the motor functions as a DC motor until its rotational speed reaches a predetermined speed to provide the starting torque, but functions as a synchronous motor which rotates in synchronism with the signals from said reference oscillator after the speed of the motor has reached said predetermined speed.

Claims

1. A system for controlling the speed of a DC motor having a rotor, a field coil mounted on a stator, said rotor being rotated by exciting currents intermittently supplied to said field coil, said system comprising a reference oscillator for generating a reference signal of a constant frequency, detector means for detecting the rotational frequency of the rotor, said detector means being arranged adjacent said rotor for detecting the position of rotation of the rotor being rotated and generating a corresponding output signal, speed control means for said motor comprising counter means for producing an output signal responsive to said reference signals from said oscillator and to said output signals from said detector means, means for applying exciting current to said field coil of said DC motor to bring said motor up to a predetermined speed and to maintain said motor at said predetermined speed responsive to the output signals from said counter means and to the output signals from said detector means, said counter means in said control means comprising a flip-flop circuit which is set in response to said signal from said reference oscillator, and is reset in response to said signal from said detector means.

2. A system for controlling the speed of a DC motor having a rotor, a field coil mounted on a stator, said rotor being rotated by exciting currents intermittently supplied to said field coil, said system comprising a reference oscillator for generating a reference signal of a constant frequency, detector means for detecting the rotational frequency of the rotor, said detector means being arranged adjacent said rotor for detecting the position of rotation of the rotor being rotated and generating a corresponding output signal, speed control means for said motor comprising counter means for producing an output signal responsive to said reference signals from said oscillator and to said output signals from said detector means, means for applying exciting current to said field coil of said DC motor to bring said motor up to a predetermined speed and to maintain said motor at said predetermined speed responsive to the output signals from said counter means and to the output signals from said detector means, said control means comprising a ring counter for distributing said signals from said reference oscillator into a pluRality of signal groups which are out of phase from one another, a flip-flop circuit interconnected between said ring counter and said rotational frequency detecting means, a logic circuit which functions in response to the inputs from said flip-flop circuit and said rotational frequency detecting means to apply its output to said field windings mounted on said stator.

3. A system for controlling the speed of a DC motor having a rotor, a field coil mounted on a stator, said rotor being rotated by exciting currents intermittently supplied to said field coil, said system comprising a reference oscillator for generating a reference signal of a constant frequency, detector means for detecting the rotational frequency of the rotor, said detector means being arranged adjacent said rotor for detecting the position of rotation of the rotor being rotated and generating a corresponding output signal, speed control means for said motor comprising counter means for producing an output signal responsive to said reference signals from said oscillator and to said output signals from said detector means, means for applying exciting current to said field coil of said DC motor to bring said motor up to a predetermined speed and to maintain said motor at said predetermined speed responsive to the output signals from said counter means and to the output signals from said detector means, said counter means in said control means comprising a reversible counter whose content is increased in response to the input signals from said reference oscillator and whose content is decreased in response to the input signals from said detector means.

4. A system for controlling the speed of a DC motor having a rotor, a field coil mounted on a stator, said rotor being rotated by exciting currents intermittently supplied to said field coil, said system comprising a reference oscillator for generating a reference signal of a constant frequency, detector means for detecting the rotational frequency of the rotor, said detector means being arranged adjacent said rotor for detecting the position of rotation of the rotor being rotated and generating a corresponding output signal, speed control means for said motor comprising counter means for producing an output signal responsive to said reference signals from said oscillator and to said output signals from said detector means, means for applying exciting current to said field coil of said DC motor to bring said motor up to a predetermined speed and to maintain said motor at said predetermined speed responsive to the output signals from said counter means and to the output signals from said detector means, said control means comprising a reversible counter adapted to carry out a predetermined number of additions and subtractions, and a plurality of logic circuits adapted to function in response to the output of said counter to feedback its output to the input terminal of said counter to carry out a predetermined number of additions and substractions.

5. A system according to claim 4 wherein said reversible counter and said plurality of logic circuits include a first logic circuit which functions in response to the signal representative of the maximum output of said counter to output '"'"''"'"''"'"''"'"'0'"'"''"'"''"'"''"'"' output, and a second logic circuit which functions in response to the signals from said reference oscillator and said first logic circuit to apply its output to said counter, whereby the maximum value of the output of said counter may be determined.

6. A system according to claim 4 wherein said reversible counter and said plurality of logic circuits comprises a first logic circuit which functions in response to the signal representative of the minimum output of said counter to output '"'"''"'"''"'"''"'"'0'"'"''"'"''"'"''"'"' output, a second logic circuit which functions in response to the output from said first logic circuit and to the signal representative of the rotational speed of said motor to apply its output to said counter, whereby the minimum value of the output of said counter may be determined.

7. A system for controlling the speed of a DC motor having a rotor, a field coil mounted on a stator, said rotor being rotated by exciting currents intermittently supplied to said field coil, said system comprising a reference oscillator for generating a reference signal of a constant frequency, detector means for detecting the rotational frequency of the rotor, said detector means being arranged adjacent said rotor for detecting the position of rotation of the rotor being rotated and generating a corresponding output signal, speed control means for said motor comprising counter means for producing an output signal responsive to said reference signals from said oscillator and to said output signals from said detector means, means for applying exciting current to said field coil of said DC motor to bring said motor up to a predetermined speed and to maintain said motor to said predetermined speed responsive to the output signals from said counter means and to the output signals from said detector means, said field coil including a plurality of field windings and said control means comprising means for distributing the motor driving current into said plurality of field windings, said driving current distribution means comprising a logic circuit which functions in response to the outputs from said counter means and said detector means to intermittently supply driving currents which are out of phase from one another to said plurality of field windings.