| 摘要 |
1,017,838. Speed-control of disc brakes. AMPEX CORPORATION. April 27, 1964 [June 4, 1963], No. 17272/64. Heading F2E. [Also in Division G3] A disc 30, rotating with shaft 18, co-operates with a photo-sensing device 32 developing a square-wave pulse signal having a frequency indicative of the speed of the shaft. When a frequency standard 36 is adjusted for a lower operational speed, comparator 34 develops a D.C. error voltage which is passed to power amplifier 23. The energization of coil 22 is increased so that a rotating brake disc 12 is urged towards fixed magnetic ring 10, and, in combination with a prestressed diaphragm 24, exerts a greater frictional force against the ring through frictional braking material 14. The shaft 18 is thus retarded until the selected speed is reached and the comparator 34 provides zero control voltage, the system maintaining the selected speed.
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