| 摘要 |
987,006. Control of D.C. motors. BROOKHIRST IGRANIC Ltd. May 15, 1963 [July 11, 1962], No. 19279/63. Heading H2J. The armature 56 of a D.C. motor is supplied from source 60 controlled by turn-off winding 70 of a magnetic amplifier, the motor field coil 58 being energized from source 92 having a similar control winding 98. Initially, rheostat 144 is set to provide a low speed signal current to control winding 126 so that magnetic amplifier 124 develops a low signal voltage across lines 120, 122. Current passes from terminal 26 through winding 70 and rectifier 32, whilst the circuit through winding 98 is blocked by rectifier 44. As a result, the armature voltage has a reduced value whilst the field voltage is at a maximum. As the signal voltage across lines 120, 122 is increased the armature voltage increases, the field voltage being reduced when the potential at line 120 exceeds that at terminal 28 whereby current passes through rectifier 44 to energize winding 98. A further increase in signal voltage causes diode 32 to block current-flow through winding 70, the armature voltage remaining at its full rated value, and the field voltage being decreased continuously. An armature current-limiting signal is derived from resistor 86, and when this signal exceeds a value set by rheostat 152, winding 128 on magnetic amplifier 124 is energized to oppose the winding 126. The motor may be supplied from a Ward Leonard generator whose field winding is excited by a magnetic amplifier. Alternatively, the magnetic amplifiers may be replaced by electronic amplifiers.
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