Monthly Archives: May 2015

24 Volt DC Motors’ Application and Characteristics

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24 volt DC motors are widely used as a drive source of all types of machinery, such as metallurgical industry of rolling mill drive, metal cutting machine tools, paper-making, printing, textile,dyeing, cement, plastic extrusion machinery. The 24 volt DC motors use polygonal structure with high space utilization rate. Its stator yoke is laminated and can be applied to the rectifier and withstand the fluctuation of the pulse current and the sharp fluctuation of the current. The magnetic pole is installed with precise positioning, so it can be well for good redirection. The insulation level of the 24 volt DC motor is F grade, and the insulation structure and the impregnation step are adopted, which ensure the insulation stability and good heat dissipation. 24 volt DC motors have the characteristics of small size, good performance, light weight, high output power, efficiency and reliability which can be contested with the international advanced-level motor.

DC Electric Motors’s Classification


DC motor is divided into brushless DC electric motor and brushed DC electric motor. Brushless DC motor which swap stator and rotor of DC motor. The rotor generates air gap flux for a permanent magnet and the stator is composed of multiple phase windings as armature. And it is similar to permanent magnet synchronous motor in the structure. Brushed DC motor’s two brushes (copper brush or carbon brush) apply the negative and positive plate of the power directly to the rotor’s commutation device through the insulating seat to be fixed on the back cover of the motor. And then the commutation device is connected to the rotor coil so that the three coil polarity continuously alternating transform with the two magnets fixed on the shell acting to form force and turn up. Because of the commutator and the rotor are fixed together and the brush and the shell (stator) are fixed together, the brush and commutator continues to produce a lot of resistance and heat generated by the friction between them when the motor rotates. So there is large loss of the brushed DC motor with a low efficiency. But it also has the advantages of simple manufacture and low cost.

Electric DC Motor’s Excitation Mode


The performance of Electric DC motor is closely related to its excitation mode. There are usually 4 types of DC motor excitation mode which are DC motor with separate excitation, DC shunt motor, DC series motor and DC compound motor. DC motor excitation mode refers that the excitation winding and armature have no electrical contact and the excitation circuit is supplied by DC power. Therefore, the excitation current is not affected by the armature voltage or armature current. DC shunt motor refers that the circuit is in parallel, shunt. And winding voltage is the armature voltage, but the excitation winding is with thin wire and its number is a lot. So it has great resistance so that the excitation current through it is small. DC series motor refers to the current series, partial pressure. The excitation winding and armature is connected in series, so the motor’s magnetic field changes significantly as the motor armature current changes. In order to avoid the excitation windings causing loss and voltage drop, the excitation winding resistance should be as small as possible. So DC series motor is usually winded by a thicker wire and it turns less. DC compound motor refers that the motor flux generated by the excitation current in the two windings.