DC Brush Motor Go-Gold 5800RPM 1.8A Used For Household Appliances

Product Description

KG-005 Household Appliance Power Tools Blender Motor DC 12V 50-100w Electric Motor

Drawing

Overview

Brush DC motors, it is clear that the force and, hence, the torque on the wire loop are at maximum when the resultant coil magnetic field vector and the magnetic field vector from the stator are orthogonal to one another (θ = 90° or 270°). As the force causes the loop to rotate, the angle θ decreases, eventually becoming zero. Analysis of the vector relationships should convince you that torque becomes zero as well. In the real world, of course, the moving coil has some angular momentum that carries it past the vertical. If, at the exact same time, we reverse the direction of the current in the loop, the polarity of the electromagnets also reverses. Now, the interaction of the two fields again generates torque, causing the coil to continue its rotation. The torque returns to peak magnitude when the loop is once more horizontal so that the rotor magnetic field is positioned orthogonal to the stator magnetic field. This process of switching current direction when the angle θ is zero or 180° is known as commutation, or commutating the motor current. The simplest way to accomplish motor commutation is with a set of mechanical switches, called, as you might expect, a commutator. A mechanical commutator consists of a number of switch contacts attached to the rotor, with each pair of contacts wired in series with a rotor coil. One or more sets of complementary contacts called brushes, which are affixed to the motor housing, contact the commutator to deliver current to the coils through the commutator (see figure 3). The brushes are connected to a voltage source so that one brush is positive and the other is negative. The commutator and brushes form a sliding switch assembly that energizes the rotor coils, reversing the direction of the current that passes through each set of windings as the rotor turns, switching the polarities of the electromagnets.