Drive speed changing appts. e.g. for motor of laboratory stirrer - comprises switchgear, with manually operated potentiometer

摘要

Equipment for switching or speed changing of drives esp. for stirrers, in which switchgear is provided for multistep rotational speed changing, includes a manually operated potentiometer which is used simultaneously for motor speed variation and for effecting gear changing, the gear changing being carried out in a potentiometer position in which the motor speed is zero or very low. The adjusting spindle (5) of the potentiometer (3) pref. has a switch cam (5a) which operates a switch (4) in or near the zero position of the potentiometer (3). Closing of the switch (4) causes prodn. of a pulse which via electronics (2) effects speed changing of the drive (1). USE/ADVANTAGE - The equipment is useful for laboratory stirrers. It provides safe switching to different rotation speed ranges and prevents unintentional speed changes.