Permanent magnet motor is a kind of high efficiency energy saving motor, which is a DC motor the specified sub is a permanent magnet only the rotor is a coil. The stator of an ordinary motor is a coil.

There are many kinds of permanent magnet motors, different structures, different use occasions. Because the permanent magnet motor has less controllable means non-adjustable excitation, different types of permanent magnet motors have different characteristics under different operating conditions.

We know that the more stable the permanent magnet motor is, the higher the efficiency, but the permanent magnet motor will also have voltage instability in use, which will cause the motor to burn out if it is treated. There are three methods usually used by permanent magnet motor manufacturers to deal with this problem:

1. Magnetic field regulation in the excitation circuit: The resistance of the permanent magnet DC motor is parallel to a suitable resistive load such as an incandescent bulb, the resistance value of the resistive load after heating is changed to obtain nonlinear resistance characteristics, so that the field resistance line the starting section of the excitation characteristics have a large intersection Angle, an obvious intersection point with the no-load characteristic curve is obtained, so that the permanent magnet DC motor will also have a stable operating point at a lower voltage.

2, magnetic grade gasket: in the magnetic grade shoe cushion into the benign magnetic conductive material, reduce the excitation field gap, can make it in the small excitation current to saturate the output characteristics, so that its output voltage to achieve stability.

3, the use of generator automatic excitation regulation device: generator automatic excitation regulation device has good excitation characteristics, with constant reactive power, constant power factor other adjustment methods, to improve the stability transient response ability of the system is very effective, can solve the output voltage instability system voltage fluctuation caused by the generator reactive power swing problem.