Brushless high speed DC vacuum cleaner motor - has electronic commutation for hazardous applications using Hall-effect sensors in permanent magnet rotor with in-built stator current limit

摘要

A brushless electronically commutated DC vacuum cleaner motor (1) with permanent magnet rotor (5) has a two-stage turbine fan (10,11) and a speed characteristic which results in rotor acceleration when the intake orifice (29) is obstructed. The motor drive employs an alternating stator field under the control of hall-effect sensors (26) and push-pull transistor output stages to produce an efficient unit capable of high speeds with high power/weight ratio. Logic circuitry determines appropriate stator current with overload limitation provided by thermal unit (35). A fixed direction of rotation is ensured by the asymmetric airgap. USE/ADVANTAGE - Particularly in areas where spark ignition of combustible dust cloud may cause explosion. Has efficient operating level at high powers and speeds, low inductance and high power/weight ratio. Vacuum increase to clear intake obstruction due to automatic increase in RPM. No commodator to cause sparking at sudden load change. Less expensive than digitally controlled alternatives.