GB1031054A - Method of and apparatus for the speed regulation of a power transmission system - Google Patents

Abstract

1,031,054. Automatic speed control. LICENTIA PATENT-VERWALTUNGS G.m.b.H. June 6,1963 [June 7,1962],No.22594/63. Heading G3R. [Also in Division H2] A load is driven by an electric motor through a resilient coupling, means being provided for suppressing oscillations of the load during the acceleration or retardation periods. For this purpose, the acceleration period is divided into three sections, and, over the first and third sections, the speed of the motor is made to vary linearly with respect to time at a rate dependent upon the ratio between the period of natural oscillation of the driven mass and the duration of the starting period of the motor. Over the intermediate second section, the speed is made to vary linearly with time from the value at the end of the first section to that at the start of the third section. As shown, motor 71 drives hoist cages 73, 74, and is supplied from transformer 77 through rectifier 76 which is controlled by an error voltage derived from comparator 79 associated with reference voltage source 80 and tachometer generator 75. The period of natural oscillation depends on the length of free cable and upon the weights of cable, the cage, and useful load. The length of cable is measured by wheel 81 associated with integrator 82, and the spring constant being measured by computer 83. A measure of the useful load is provided by current transformer 84 associated with computer 85 taking into account the known weights of the cage and cable. The natural oscillation period is calculated by summation device 86, the components representing the duration of the starting period and the natural oscillation period being supplied to computer 87 which adjusts the reference voltage source 80. In one arrangement, the reference voltage is derived from a potentiometer whose movable tap is displaced at a constant speed, and which has two fixed tappings through which variable supplementary voltages are fed into sections of the potentiometer. These supplementary voltages are derived from two auxiliary potentiometers whose movable taps are ganged and adjusted in accordance with the signal from computer 87, Fig. 4 (not shown). In another arrangement, the reference voltage is derived from an integrator associated with a summation device and four step-function transmitters, Fig. 5 (not shown). In a further embodiment, the reference voltage is obtained from a potentiometer which is adjusted by a cam, Fig. 6 (not shown). The position of the cam is related to that of the lift cage.