Method of controlling an electric motor
AssigneeU.S. Philips Corporation
InventorPaul Antonius Ferdinand van Acker
Life of this patent
Estimating the term…
Abstract
A method of controlling a motor in which an elastic element is coupled in a sub-critically damped manner to the load and the natural frequency of the system which comprises the elasticity of the element and the mass of the driven part is utilized to cause the speed of the load to increase and to decrease as quickly as possible.
Claims9
A method of controlling a motor coupled to a load in an elastic subcritically damped manner wherein a speed variation is effected in at least one velocity step made up of two stages and comprising, bringing the motor from a first speed to a second speed during the first stage of said step whereupon the load initially persists in its initial movement and then moves towards its equilibrium position relative to the motor, and bringing the motor from the second speed to a third speed at a time during the second stage of said step such that the third speed is reached when the load reaches the said equilibrium position for the first time, the speed difference between the motor and the load then being substantially equal to zero.
A speed control arrangement for a motor coupled to a load in an elastic sub-critically damped manner comprising, a control device having an output coupled to a speed regulator which in turn is connected to the motor and is adapted to adjust the motor speed to at least three distinct values under the command of said control device, a signal generator having an output connected to an input of said control device and arranged to apply a signal to the control device after the motor speed has been changed by the control device from a first value to a second value but before the load has reached its equilibrium position relative to the motor, the control device being responsive to said signal to cause the motor to reach a third value of speed by means of the speed regulator at the instant at which the load has for the first time substantially reached said equilibrium position relative to the motor whereby the speed difference between the load and the motor is substantially equal to zero at said instant of equilibrium.
In a motor speed control system wherein the load is elastically coupled to the motor, the system comprising, a control device having an output coupled to an input of a speed regulator device, means connecting the output of said speed regulator to the motor, said speed regulator being responsive to command signals from the control device to adjust the motor speed to at least three distinct values in sequence, a signal generator having an output connected to an input of the control device for applying a signal thereto at a time after the motor speed has been changed under command of the control device from a first speed to a second speed but before the load has reached an equilibrium position relative to the motor for the first time, the control device being responsive to said signal to command the speed regulator to adjust the motor speed to a third value which is substantially equal to the load speed at the instant the load for the first time reaches said equilibrium position.
Dependencies are inferred from the claim text.