Dc energized timing motor utilizing a resonant member to maintain constant speed

Claim 2

A DC energized timing motor comprising a motor portion including a rotor, a stator and a common winding, said motor portion being responsive to torque pulses generated by current pulses to the winding in timed relation to rotor and stator position to drive the rotor, with change in the lag-lead characteristics of the torque pulses with respect to rotor-stator position effecting a change in rotor acceleration-deceleration characteristics, the invention comprising a resonator to furnish a frequency reference; a direct permanent magnetic coupling between the resonator and the rotor to excite the resonator to its resonant frequency when the rotor achieves synchronous speed; pickup means responsive to resonant action of the resonator to furnish output signals; a source of DC power; circuit means, including power amplifier means connected to the DC source, to the winding, and to the pickup means and responsive to the signal from the pickup means to supply current pulses to the winding to generate torque pulses; means to isolate the pickup means of the resonator from the rotor to preclude rotor-induced signals in the pickup means capable of operating the motor; and means to preset the angular position of the resonator and its pickup in phase advance relative to geometrical phase angle zero thereby to establish torque pulses which increase in magnitude with decrease in rotor speed and which decrease in magnitude with increase in rotor speed, thereby to stabilize the motor around synchronous speed.

Claim 3

Apparatus as set forth in claim 1, said motor and its winding exhibiting characteristics which limit the magnitude of the current pulses primarily by the winding resistance, said phase advance of the resonator being substantially less thAn 90* to generate a net torque differential between accelerating and retarding torque to match the motor load.

Claim 4

Apparatus as set forth in claim 1, said motor including a winding, stator and rotor exhibiting characteristics resulting in the drive current pulses being limited primarily by winding inductance and back electromotive force, said phase advance of the resonator being 90* plus an additional increment to advance the effective midpoint of the current pulses in the winding to occur prior to the point of maximum back electromotive force.

Claim 5

Appratus as set forth in claim 1, including timing control means to adjust the relative angular positions of the resonator and stator in a narrow range around the preset phase-advance point thereby to effect a timekeeping adjustment of the motor not involving motor stability.

Claim 6

A DC energized timing motor comprising a motor portion including a rotor, a stator and a common winding, said motor portion being responsive to torque pulses generated by current pulses to the winding in timed relation to rotor and stator position to drive the rotor, with change in the lag-lead characteristics of the torque pulses with respect to rotor-stator position effecting a change in rotor acceleration-deceleration characteristics; the invention comprising a resonator to furnish a frequency reference; a direct permanent magnetic coupling between the resonator and the rotor to excite the resonator to its resonant frequency when the rotor achieves synchronous speed; pickup means responsive to resonant action of the resonator to furnish output signals; a source of DC power; circuit means, including power amplifier means connected to the DC source, to the winding and to the pickup means and responsive to the signal from the pickup means to supply current pulses to the winding to generate torque pulses; means to isolate the pickup means of the resonator from the rotor to preclude rotor-induced signals in the pickup means capable of operating the motor; and rotor pickup means to generate signals reflecting the passage of successive rotor poles, said rotor pickup means being separated from said resonator pickup means to afford an independent output signal connected to said circuit means.

Claim 7

A DC energized timing motor comprising a motor portion including a rotor, a stator and a common winding, said motor portion being responsive to torque pulses generated by current pulses to the winding in timed relation to rotor and stator position to drive the rotor, with change in the lag-lead characteristics of the torque pulses with respect to rotor-stator position effecting a change in rotor acceleration-deceleration characteristics; the invention comprising a resonator to furnish a frequency reference; a direct permanent magnetic coupling between the resonator and the rotor to excite the resonator to its resonant frequency when the rotor achieves synchronous speed; pickup means responsive to resonant action of the resonator to furnish output signals; a source of DC power; circuit means, including power amplifier means connected to the DC source, to the winding and to the pickup means and responsive to the signal from the pickup means to supply current pulses to the winding to generate torque pulses; means to isolate the pickup means of the resonator from the rotor to preclude rotor-induced signals in the pickup means capable of operating the motor; and rotor pickup means to generate signals reflecting the passage of successive rotor poles, said rotor pickup means being separated from said resonator pickup means to afford an independent output signal connected to said circuit means.

Claim 8

Apparatus as set forth in claim 1, including bias means in said circuit means to reduce the duration of the torque pulses.

Claim 9

Apparatus as set forth in claim 5, including bias means to control the duration of the torque pulses to less than 180* of geometrical phase angle.

Claim 10

Apparatus as set forth in claim 5, said circuit means including means responsive to the rotor pickup means to cut off rotor decelerating pulses to the motor winding, said motor thereby being energized by only rotor accelerating pulses, and means responsive to change in rotor phase angle relative to the resonator to change the duration of the accelerating pulses to maintain synchronism under varying load conditions and under varying supply voltage from the DC source.

Claim 11

Apparatus as set forth in claim 5, including circuit means to selectively utilize the rotor and resonator pickup signals, whereby the rotor pickup signals control the current and torque pulses between zero and slightly above synchronous rotor speeds, and the pickup signals from the resonator control the current and torque pulses at synchronous speed.

Claim 12

Apparatus as set forth in claim 5, including circuit means connected to said rotor and resonator pickup means, said circuit means, at synchronous speed, responding to the resonator pickup signals to initiate each of the current pulses and responding to the rotor pickup signals to turn off each of the current pulses, whereby change in duration, both increasing and decreasing, maintains synchronism.

Claim 13

Apparatus as set forth in claim 10, including circuit means responsive to the rotor pickup signals to energize the winding in the absence of resonator pickup signals. 12, Apparatus as set forth in claim 5, said motor and its wiNding exhibiting characteristics which limit the magnitude of the current pulses primarily by the winding resistance, said circuit means including a rotor pickup circuit and a resonator pickup circuit to control cooperatively the energization of the winding, said rotor pickup circuit including means to produce current and torque pulses terminating at a predetermined phase angle, said resonator pickup circuit including means to delay the initiation of the current and torque pulses when the resonator is at resonance, and amplifier means responsive to the signals to energize the motor winding with controlled torque pulses which decrease in duration when the rotor accelerates from synchronism and which increase when the rotor decelerates from synchronism.

Claim 14

Apparatus as set forth in claim 10, said rotor pickup circuit and said resonator pickup circuit each including switch means connected in series with each other and with the motor winding, said circuit means for the rotor pickup including means to close its switch when the rotor is not more than 180* in advance of geometrical phase angle zero, said circuit means for the resonator pickup including means to close its switch at no more than 90* in advance of geometrical phase angle zero when the resonator is operating at resonance and to open its switch before the rotor circuit switch closes for initiating the next successive pulse.

Claim 15

Apparatus as set forth in claim 13, including bias means in said resonator pickup circuit to close the switch in the absence of a signal from said resonator pickup means, whereby until resonance occurs in the resonator the motor is energized continuously under the control of signals from said rotor pickup means.

Claim 16

Apparatus as set forth in claim 5, said motor including a winding, stator and rotor exhibiting characteristics resulting in the drive current pulses being limited primarily by winding inductance and back electromotive force, said circuit means being responsive to both resonator pickup signals and rotor pickup signals to generate current and torque pulses having only rotor-accelerating characteristics and having a duration less than 180* of geometrical phase angle, and means to locate the pulses with their effective midpoints occurring substantially at the instant of peak back electromotive force in the motor, thereby to stabilize the motor at synchronous speed by effecting compensating changes in pulse width.

Claim 17

Apparatus as set forth in claim 5, said motor including a winding, stator and rotor exhibiting characteristics resulting in the drive current pulses being limited primarily by winding inductance and back electromotive force, said circuit means being responsive to both resonator pickup signals and rotor pickup signals to generate current and torque pulses having only rotor-accelerating characteristics and having a duration less than 180* of geometrical phase angle, and means to locate the pulses with their effective midpoints in phase advance with respect to the instant of peak back electromotive force in the motor, thereby to stabilize the motor at synchronous speed by effecting compensating changes in current pulse width and magnitude.

Claim 18

Apparatus as set forth in claim 10, including means to advance the phase angle of the resonator relative to the rotor and at the same time to retard the phase angle of the rotor relative to the resonator under increasing load or decreasing supply voltage or both, and means to retard the phase angle of the resonator relative to the rotor and at the same time to advance the phase angle of the rotor relative to the resonator under decreasing load or increasing supply voltage, or both, whereby the duration of each drive pulse to the winding is changed in the appropriate direction to increase or decrease the duration of the pulses to maintain the rotor in synchronism with the resonator.

Claim 19

A DC energized timing motor comprising a motor portion including a rotor, a stator and a common winding, Said motor portion being responsive to torque pulses generated by current pulses applied to the winding in timed relation to rotor and stator position to drive the rotor, with change in the lag-lead characteristics of the torque pulses with respect to relative rotor-stator position effecting a change in rotor acceleration-deceleration characteristics; the invention comprising oscillator means to generate a train of control pulses of uniform frequency; pickup means responsive to rotor motion to furnish a train of control pulses each terminating no later than substantial alignment of rotor and stator poles a source of DC power; and circuit means, including power amplifier means having a pair of series connected switches respectively connected to the oscillator means and the pickup means to be activated by the control pulses therefrom, thereby to connect the DC source to the winding when both switches are closed said pickup means for the rotor being positioned to close its switch when the rotor is not more than substantially 180* in advance of alignment of rotor and stator poles, said oscillator means normally closing its switch while the pickup switch is closed and opening its switch between the time the pickup switch opens and then closes for initiating the next torque pulse, whereby change in rotor speed changes the phase relation between the torque-initiating signal from the oscillator means and the torque-terminating signal from the rotor pickup means to change the accelerating torque-pulse width, whereby the rotor is returned to synchronism.

Claim 20

A DC energized timing motor comprising a motor portion including a rotor, a stator and a common winding, Said motor portion being responsive to torque pulses generated by current pulses applied to the winding in timed relation to rotor and stator position to drive the rotor, with change in the lag-lead characteristics of the torque pulses with respect to relative rotor-stator position effecting a change in rotor acceleration-deceleration characteristics; the invention comprising oscillator means to generate a train of control pulses of uniform frequency; pickup means responsive to rotor motion to furnish a train of control pulses each terminating no later than substantial alignment of rotor and stator poles a source of DC power; and circuit means, including power amplifier means having a pair of series connected switches respectively connected to the oscillator means and the pickup means to be activated by the control pulses therefrom, thereby to connect the DC source to the winding when both switches are closed said pickup means for the rotor being positioned to close its switch when the rotor is not more than substantially 180* in advance of alignment of rotor and stator poles, said oscillator means normally closing its switch while the pickup switch is closed and opening its switch between the time the pickup switch opens and then closes for initiating the next torque pulse, whereby change in rotor speed changes the phase relation between the torque-initiating signal from the oscillator means and the torque-terminating signal from the rotor pickup means to change the accelerating torque-pulse width, whereby the rotor is returned to synchronism.

Claim 21

Apparatus as set forth in claim 1, said resonator comprising a resonator having a central nodal point and at least four concomitantly vibrating arms, and being disposed with its nodal point arranged coaxially with the rotor and coplanar therewith. 20 Apparatus as set forth in claim 19, said resonator comprising a cruciform plate.

Claim 22

Apparatus as set forth in claim 19 including first magnetic means on the resonator to coact with the rotor to excite the resonator when the rotor is driven at a predetermined synchronous speed, and second magnetic means spaced from the first to excite the resonator pickup means.