Dc Motor

Continental Automotive Systems är ett tyskt företag som utvecklar styrsystem för olika tillämpningar i bilar. Bland annat utvecklas ett styrsystem till eldrivna bakluckor som öppnas och stängs av föraren per knapptryck. Själva drivanordningen består av en skruv som drivs av en likströmsmotor över en utväxling och en fjäder. READ MOREBrushless DC Motors are an important class of highly efficient electric motors. They are most frequently used in electric vehicles because of their high efficiency and high power density. They are also present in the small DC fans used in power supplies and CPU coolers.

In order to discuss the Brushless DC Motor it is important to first have a basic understanding of the more common Brushed DC Motor which is present in many household items. The brushed DC motor consists of a rotor (the part that rotates) containing several coils of wire. This is attached to the output shaft. The rotor is surrounded by a magnetic field (this is usually a permanent magnet, but can be an electro magnet). Electrical connection to the rotor is accomplished via a device called a commutator. A commutator is basically a conductive ring that rotates with the rotor shaft. This ring has been split into segments (there are as many segments as there are coils) that are insulated from one another, but which are connected to the leads of the coils. A pair of carbon or brass brushes are positioned on either side of the commutator rub against it making electrical connections. The commutator segments are oriented relative to the permanent magnets such that when one coil is energized it will generate an electro-magnetic field that will repel or attract the permanent magnets. This causes a torque on the rotor, and the shaft turns. As the shaft turns, different segments of the commutator come into contact with the brushes, and different coils are excited. The result is that the shaft will continually rotate.

Brushless DC Motors are composed of a rotor (the part that