| 摘要 |
<p>791,054. Automatic control systems; exciting dynamos. GENERAL ELECTRIC CO. Dec. 14, 1954 [Dec. 14, 1953], No. 36196/54. Classes 35 and 38 (4). [Also in Groups XXXIX and XL (c)] Automatic control.-A dead band is introduced into a servo-control system (used in an unspecified manner for an unspecified purpose) by providing the amplifier with degenerative feedback which reduces the gain only when the input signal is small. Almost full gain is obtained for large input signals by shunting the feed-back loop with a pair of biased diodes which conduct when the signal exceeds a preset level. The amplifier may be either an amplidyne, see below; a magnetic amplifier (see Group XXXIX); or a thermionic valve amplifier (see Group XL (c)). Exciting dynamos.-An amplidyne generator 1 for the control system above has a feed-back winding 10, which opposes the main control winding 8, connected across the output terminals of the generator in series with a variable resistor 1, thus reducing the effective gain of the generator as an amplifier. The winding 10 is shunted by reversely poled rectifiers 17, 21, each in series with a biasing source 13, 19. When the output voltage exceeds the level set by the biasing sources 13, 19, the appropriate diode 17 or 21 (according to polarity) conducts and reduces the feed-back and hence provides almost full gain for large input signals, whilst the arrangement has a small gain for small input signals. Specifications 497,060, [Group XL], and 665,541, [Group XXXVIII], are referred to.</p> |
