Publish Time: 2023-01-03 Origin: Site
The stator pole (main pole) of an electromagnetic DC motor consists of an iron core and an excitation winding. According to the different excitation methods (the old standard is called excitation), it can be divided into series-excited DC motors, shunt-excited DC motors, separately-excited DC motors and compound-excited DC motors. Due to the different excitation methods, the laws of the stator pole magnetic flux (generated by the energization of the stator pole excitation coil) are also different.
Here is the list
Series Excited DC Motor
Parallel DC Motor
Separately excited DC motor
The excitation winding and rotor winding of series-excited DC motor are connected in series through brushes and commutators. The field current is proportional to the armature current. The magnetic flux of the stator increases with the excitation current, and the torque is about the same as the current. Pivot current is proportional to the square, and rotational speed drops rapidly as torque or current increases. The starting torque can reach more than 5 times the rated torque, the short-term overload torque can reach more than 4 times the rated torque, the speed change range is large, and the no-load speed is very high (generally, no-load operation is not allowed). ). Speed regulation can be achieved by using external resistors in series (or parallel) with the series windings, or by switching the series windings in parallel.
The excitation winding of the parallel DC motor is connected in parallel with the rotor winding, the excitation current is relatively constant, the starting torque is proportional to the armature current, and the starting current is about 2.5 times the rated current. The speed decreases slightly with the increase of current and torque, and the short-time overload torque is 1.5 times of the rated torque. The speed change rate is small, 5%~15%. The speed can be adjusted by weakening the constant power of the magnetic field.
The excitation winding of the separately excited DC motor is connected to an independent excitation power supply, and its excitation current is relatively constant, and the starting torque is proportional to the armature current. The speed change is also 5%~15%. The rotational speed can be increased by weakening the field constant power or by reducing the voltage of the rotor windings.
In addition to the parallel windings, the stator poles of compound DC motors are also equipped with series windings (with fewer turns) in series with the rotor windings. The direction of the magnetic flux generated by the series winding is the same as that of the main winding, the starting torque is about 4 times the rated torque, and the short-term overload torque is about 3.5 times the rated torque. The speed change rate is 25%~30% (related to the series winding). The rotational speed can be adjusted by weakening the magnetic field strength.
The AC synchronous motor is a constant-speed drive motor, and its rotor speed is proportional to the frequency of the power supply. Widely used in electronic instrumentation, modern office equipment, textile machinery, etc.
Hangzhou New Hengli Electric Machine MFG. Co., Ltd. has been named the provincial advanced enterprise by Zhejiang provincial government and become a state grade-2 enterprise in 1988. Our motor max-power reaches 15000kW (A.C. motor), 2800kW (D.C. motor), and max-center-high dimension of our motor reaches 1250mm.