| 摘要 |
An out-of-balance control for a laundry machine is described. The input to the control is a current signal which is proportionate to the current drawn by a motor which rotates a perforated drum into which fabric goods are loaded. When the drum is accelerated from a relatively low speed, employed to a washing cycle, to a somewhat higher, distribution speed, the input to the control is a "real time" signal which reflects variations in torque required to rotate the drum. The magnitude of these variations is proportional to load unbalance which can cause radial displacement of the drum, machine vibration and damage to its components. The real time signal is averaged. A differential amplifier then subtracts the "average" signal from the "real time" signal, providing an "unbalance torque" signal of alternating polarity. When the "unbalance torque" signal exceeds a given magnitude, reflecting the maximum permissible centrifugal force to be generated by load unbalance, an "unbalance control" signal is generated. The main control of the machine is responsive to this last signal to reduce the rotational speed of the drum. |
