摘要:
A power tool in accordance with an embodiment of the invention has a motor driving a member, a switch coupled across windings of the motor that dynamically brakes the motor, and a mechanical brake that brakes speed of the member. In an aspect, the combined dynamic and mechanical braking brakes speed of the member to a desired speed in no more than about two second. In an aspect, the motor is an electronically commutated motor and the power tool includes a controller that electronically commutates the motor by switching switches that switch power to the motor in an electronic commutation sequence and switches the switches to electronically brake the motor.
摘要:
A hand held orbital sander has a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing. A motor controller is coupled to the motor. The motor controller changes the speed of at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changes the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value. The sander may have a mechanical brake that brakes the orbit mechanism and the motor controller also dynamically brakes the motor.
摘要:
A system of electric power management for a hybrid vehicle includes an engine, a first inverter, a first electric machine coupled to the engine and the first inverter, and a first transmission coupled between the engine and the first electric machine. The first transmission has a transmission speed ratio operable such that the first electric machine operating speed operates independent of an engine operating speed. A second electric machine is coupled to the second inverter and a wheel axle of the vehicle. A high voltage battery is coupled to both the first inverter and the second inverter. A switch box is disposed between the first electric machine and the second electric machine. The switch box includes switches adapted to switch open and closed to allow direct electrical connection from the first electric machine to the second electric machine.
摘要:
A power tool is a “low profile” power tool, that is the overall height of the power tool is sufficiently small that a user can grasp the top of the power tool with the user's hand and the hand will be positioned relative close to the bottom of the power tool compared with existing power tools. The low profile power tool uses a low profile motor having a diameter to lamination height ratio of at least 2:1. In an aspect of the invention, the motor is an electronically commutated “pancake” style motor. In an aspect of the invention, the power tool is a random orbital sander or an orbital sander having a motor that provides at least 40 watts of power. In an aspect of the invention, the sander has a mechanical brake that brakes the orbital mechanism and the motor is dynamically braked.