Horizontal force component prodn. for vibrating sieve - use two unbalanced motor one switchable to freewheel to change vibration vector

摘要

A vibrating sieve is driven by a pair of electric motors (1) (2) with parallel shafts rotating in opposite directions (5) (6) and with eccentric weights (3) (4). Such motors are normally synchronised so that resultant out-of-balance force acts only in the vertical direction. If the motor (2) is switched off, it continues to run under no-load conditions but with a phase lag (7) relative to the powered motor (1). This changes the direction of the resultant force providing a small horizontal component which is useful for freeing a blocked sieve. The speed of the drive falls by about 1% to 2% and the power of the driving motor increases by 5%.