Abstract: An air conditioning system includes a refrigeration cooling coil in fluid communication with process air, a refrigeration circuit containing refrigerant, a heat exchanger in fluid communication with the refrigerant and water, the heat exchanger adapted to transfer heat from the refrigerant to the water, a hot water coil in fluid communication with the water, a desiccant rotor having a process portion in fluid communication with the process air and a reactivation portion, and a reactivation blower adapted to move reactivation air over the hot water coil and through the reactivation portion of the desiccant rotor. A method of conditioning air is also described.

Abstract: A current control circuit that employs a magnetic amplifier and an active feedback circuit. The feedback circuit establishes the effective operating current of the amplifier at a fixed point. The magnetic amplifier includes a pair of oppositely wound gate windings, a bias winding and a control winding. The gate windings are driven by an oscillator driver that generates a gate winding current and a gate winding voltage. A reference voltage and the gate winding voltage are applied to a feedback amplifier and the feedback circuit. When the gate winding voltage becomes equal to the reference voltage, the feedback circuit is stable and the gate winding current is set to a desired zero current operating point.

Abstract: A trimming tool includes a selectable blade attachment for effecting a conversion between a string trimming mode and a blade trimming mode without requiring disassembly of the unit. The assembly includes a locking mechanism selectively engageable with a pivoting trimming blade that pivots between a retracted position and an extended position by centrifugal force. In one embodiment, the locking mechanism is reciprocated between the locked position and the unlocked position based on a rotation direction of the motor. The locking mechanism itself may also be reciprocated by centrifugal force. A spool lock, which is also positioned by centrifugal force, disables automatic string feeding in the blade trimming mode. The trimming tool may also be provided with a blower function incorporating a blower attachment readily attachable as a trimming guard of the trimming tool or a blower assembly integrated into the tool components.

Abstract: A trimming tool includes a selectable blade attachment for effecting a conversion between a string trimming mode and a blade trimming mode without requiring disassembly of the unit. The assembly includes a locking mechanism (46) selectively engageable with a pivoting trimming blade (40) that pivots between a retracted position and an extended position by centrifugal force. In one embodiment, the locking mechanism is reciprocated between the locked position and the unlocked position based on a rotation direction of the motor. The locking mechanism itself may also be reciprocated by centrifugal force. A spool lock, which is also positioned by centrifugal force, disables automatic string feeding in the blade trimming mode. The trimming tool may also be provided with a blower function incorporating a blower attachment readily attachable as a trimming guard of the trimming tool, or a blower assembly integrated into the tool components.

Abstract: A trimming tool includes a selectable blade attachment for effecting a conversion between a string trimming mode and a blade trimming mode without requiring disassembly of the unit. The assembly includes a locking mechanism (46) selectively engageable with a pivoting trimming blade (40) that pivots between a retracted position and an extended position by centrifugal force. In one embodiment, the locking mechanism is reciprocated between the locked position and the unlocked position based on a rotation direction of the motor. The locking mechanism itself may also be reciprocated by centrifugal force. A spool lock, which is also positioned by centrifugal force, disables automatic string feeding in the blade trimming mode. The trimming tool may also be provided with a blower function incorporating a blower attachment readily attachable as a trimming guard of the trimming tool, or a blower assembly integrated into the tool components.