| 摘要 |
<p>871,999. Automatic speed-control systems. LANCASHIRE DYNAMO ELECTRONIC PRODUCTS Ltd. Dec. 11, 1958 [March 24, 1958], No. 9431/58. Class 38 (4). The field excitation of a Ward-Leonard generator is controlled by variable width current pulses from a transistor amplifier which is controlled by a switching saw-tooth waveform and a D.C. control signal. The field 1 of the generator G is energized by transistors T5, T6 controlled via an amplifier T3, T4, by a bi-stable pair of transistors T1, T2, to which are applied a control current and a switching saw-tooth. The control current is the difference between a speed reference voltage generated at 30 and a voltage proportional to the back E.M.F. of the motor M applied over lead 4. The saw-tooth signal is obtained by integrating the output of transistors T5, T6 in an R.C. network 3.</p> |
