Circuit arrangement for maintaining the speed of a DC motor constant
AssigneeU.S. Philips Corporation
InventorsPeter Johannes Michiel Janssen, Petrus Josef Maria Aarts
Life of this patent
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Abstract
Circuit arrangement for stabilising the speed of a d.c. motor which is controlled via a control amplifier, and drives a tacho-meter which is connected between the bases of a "long-tailed pair," a tuned circuit being included between the collectors which is tuned to the tacho frequency and which attenuates the other frequencies, the voltage across the tuned circuit being applied to the control amplifier via a charge pump.
Claims8
A system for regulating the speed of a dc motor at a desired speed comprising, a control amplifier connected in series with the motor winding for controlling the current supplied to said winding, the motor driving a tacho-generator which supplies a voltage whose frequency is directly proportional to the speed of the tacho-generator, a filter comprising a tuned circuit having a resonant frequency equal to the tacho-generator frequency at the desired motor speed and which attenuates other frequencies, means for coupling the tacho-generator voltage via said filter to a charge pump rectifying circuit having an output connected to the control input of the control amplifier, said filter and charge pup rectifying circuit being responsive to the tacho-generator voltage to supply a DC control voltage to said control input of the control amplifier in a sense to maintain the motor at said desired speed.
An electrical system for regulating the speed of a motor comprising, a voltage generator coupled to a drive shaft of the motor for generating a voltage whose frequency is proportional to the motor speed, a control amplifier coupled to the motor to control the current supplied to the motor from an electric energy source, a filter comprising a resonant circuit tuned to the frequency of the voltage generator output voltage corresponding to the desired speed of the motor, a capacitor charge pump circuit for converting the frequency of an input signal into a corresponding DC voltage that is independent of the amplitude of the input signal, first means for coupling the output of the voltage generator to the input of the charge pump circuit via said filter, said filter being operative to transmit a signal at its resonant frequency to the charge pump input and to attenuate all other signal frequencies, and second means for coupling the output of the charge pump circuit to a control terminal of the control amplifier to apply a control voltage thereto in a sense to maintain the motor at the desired speed.
Dependencies are inferred from the claim text.