Patent ID: 8491685

Claim:
A dust collection arrangement, comprising; a dust separator having an inlet port to which ducting is connected to bring a flow of air and entrained dust from one or more dust-producing tools, a separator mechanism for separating the dust from the air flow, and an exhaust for discharging the air; including a rotary impeller that is rotated by an alternating current (AC) drive motor; the impeller being adapted to induce said air flow through said ducting into and through the dust separator; a variable speed drive having a power inlet receiving line power, and power outputs providing single phase or polyphase drive power at a drive frequency to said AC motor, including a control circuit for varying the drive frequency of the AC drive power provided by the variable speed drive; a current sensor detecting the amount of drive current being supplied from the variable speed drive to said AC motor; and a feedback mechanism associated with the current sensor and the variable speed drive control circuit for adjusting the drive frequency of the drive power provided from the power outputs of the variable speed drive to said motor on the basis of amount of current detected by said current sensor, so as to increase or decrease the frequency such as to maintain the current at a predetermined current level.