| 摘要 |
In a yarn storage feeder system of the type disclosed in U.S. Pat. No. 4,226,379 and having a yarn storage unit upon which a quantity of yarn is maintained from a yarn supply for intermittent withdrawal and delivery to yarn feeding and/or consuming means, such as a loom, and in which the yarn storage unit is driven by a low inductance DC motor such as a flat armature or pancake DC motor powered by a full wave rectified AC current, a significant improvement in motor operating efficiency, especially output torque, is achieved by incorporating an electrical choke in the circuit supplying such current to the DC motor. In the operation of the system the output speed of the motor is monitored and the current flow to the motor is controlled to maintain a preset reference speed by an SCR phase control unit, preferably through a transistor included in the motor circuit and having its base biased by the output of the SCR unit in synchronism with the frequency of the rectified AC current for a fraction of the duration of the current pulses, the extent of the fraction being adjusted to maintain the motor output speed at the reference level. The quantity of collected yarn can also be monitored and the speed control unit momentarily deactivated if that quantity exceeds a predetermined amount.
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