Views: 0 Author: Site Editor Publish Time: 2023-07-11 Origin: Site
Conventional Z4 series DC motors are complex in structure, difficult to manufacture, consume more materials, and have higher production costs. Moreover, they typically have commutators and carbon brushes, which affect long-term reliable performance and require significant maintenance effort and cost, along with high technical requirements for maintenance personnel. In contrast, AC induction servo motors do not have these drawbacks of DC motors. They require minimal maintenance and can achieve higher voltage and speed, with larger capacities compared to DC motors. In recent years, with the development of power electronics and AC variable speed drive technology, servo motors and servo drives have been continuously improved, particularly with rapid advancements in AC servo drive systems in the field of transmission. The main advantages of AC servo motors are as follows:
Compared to DC motors:
The series features a square-shaped external structure, similar to the overall appearance of the Z4 series DC motors.
The motor has a simple overall structure: the rotor is a squirrel-cage type without windings, typically made of cast aluminum. It does not require power supply and has simple peripheral wiring with only three power supply lines. In contrast, conventional Z4 DC motors require power supply for both armature and excitation, often with different power supply levels, making the power supply process more cumbersome.
The stator winding is closely attached to the motor housing, allowing for convenient heat dissipation. The core of the motor housing is made of laminated silicon steel sheets, which have good magnetic and thermal conductivity properties.
The motor has low inertia, fast system response speed, and can achieve wide-frequency, high-speed, and high-precision control.
It is suitable for high-speed and high-torque working conditions, such as applications in rolling equipment that require high-speed and high-torque characteristics.
It has smaller volume and weight for the same power rating. The fully laminated and frameless structure improves material utilization, resulting in a reduction of the motor center height by two to three levels compared to conventional motors with the same torque.
AC servo motors are designed with excellent ventilation and equipped with low-noise cooling fans, resulting in low operating noise.
They have reliable and safe operation, without serious accidents like demagnetization that may occur in DC motors, which can cause significant losses to personnel and equipment.
AC induction servo motors do not require dedicated servo drives and can operate with general-purpose inverters. They can work with variable frequency power supply (speed control mode) and ordinary commercial power supply (no speed control mode). With the addition of a drive and rotary encoder, higher speed accuracy and smoother operation can be achieved. In contrast, conventional DC motors require corresponding DC drive devices to control the motor after completing the AC-DC power conversion.
The cost of the drive system is cheaper and more convenient to maintain compared to DC systems. For the same power rating, AC induction servo systems are relatively cheaper than conventional DC drive systems, especially in the low-power range (below 75 kW). As general-purpose inverters have reversible characteristics, AC induction servo systems have a more significant price advantage for reversible (forward and reverse) operation systems.
AC induction servo motors have lower environmental requirements compared to DC motors and exhibit stronger adaptability to harsh working conditions.
Due to its simple structure with only stator windings and rotor without windings, AC induction servo motors have lower repair difficulty, shorter repair duration, and lower repair costs compared to DC motors. In terms of repair, AC induction servo motors have significant advantages over DC motors in terms of difficulty, duration, and price.
The compact size allows for a wider range of applications in spaces with limited usage. This advantage is particularly prominent in the machine tool industry.
They have excellent overload capacity, typically achieving 2.0 to 2.8 times the overload capacity (1 minute). This greatly helps overcome the inertia torque load during startup. This advantage is particularly noticeable when used in high-speed stamping machine tools.
Compared to conventional YVP series AC variable frequency motors:
Conventional YVP series variable frequency motors have relatively larger dimensions.
The cooling fan of conventional YVP series variable frequency motors is installed at the rear of the motor, cooling only the surface, and lacks internal airflow channels, resulting in poor cooling effectiveness.
The rear-mounted cooling fan of conventional YVP series variable frequency motors affects the installation of motor accessories at the rear (such as encoders, overspeed switches, brake actuators).
Due to the presence of the rear cooling fan in conventional YVP series variable frequency motors, the overall length of the motor is larger, which restricts usage in space-constrained applications. Additionally, the rear fan cannot be relocated, unlike AC induction servo motors, which offer flexible fan installation at the top, rear, or even side.
The overload capacity of conventional YVP series variable frequency motors is generally below 2.0 times and cannot match AC induction servo motors.
The motor housing of conventional YVP series variable frequency motors is made of castings with a rough surface, lacking aesthetic appeal. In contrast, the motor seat of AC induction servo motors is formed by laminated silicon steel sheets, featuring a square structure that is easy to process, resulting in a flat and aesthetically pleasing surface.
Applications:
AC induction servo motors are widely used in rubber and plastic machinery (such as plastic machinery, rubber machinery, tire machinery), pumps (such as water pumps, hydraulic pumps), fans (such as induced draft fans), machine tool main spindle motors (such as CNC lathes), crushing, grinding, chip cutting, traction, lifting, electrical machinery (such as wire drawing machines, stranding machines), high-speed stamping machine tools, metallurgical industry, rolling mill industry, steel pipe industry (such as high-frequency welding pipe units, steel pipe cold drawing units), cement industry, packaging (food packaging machinery), material conveying (such as belt conveyors), chemical industry, papermaking, printing and dyeing, military industry, and high-tech fields.
Technical standards and manufacturing specifications:
Motor power: 7.5 kW - 1250 kW
Motor pole number: 2, 4, 6, 8, 10, 12 poles
Output torque: 48 - 12000 Nm
Base speed: 500, 750, 1000, 1500 rpm, etc. (other speeds can also be selected)
Rated voltage: 3AC 380V, 3AC 660V, etc. (other voltages can also be selected)
Rated frequency: 50Hz, and can be selected as 20Hz, 25Hz, 33.3Hz, 60Hz as required.
Speed control mode: In open-loop U/f control, constant torque control is achieved from 3Hz to the rated frequency, and constant power control is achieved from the rated frequency to the highest set frequency. In vector control conditions, the constant torque control range can be extended from zero speed to the base speed.
Duty: Motor's standard duty is S1, but other duties can be adopted as required.
Insulation class: F class (maximum allowable temperature of 155°C)
Mounting method: B3 (horizontal foot-mounted)/B35 (horizontal and vertical mounting: both foot and flange can be installed) or other customized mounting methods.
Protection class: The standard protection class is IP23, but it can be increased to IP44, IP54, etc., by adding air-water cooling or air-air cooling.
Cooling method: The standard cooling method is forced air cooling (IC06). The voltage of the cooling fan installed is three-phase AC asynchronous motor, with a voltage of 3AC_380V_50Hz. Other voltages or frequencies need to be specified. The cooling method can also be customized to include independent cooling, such as air-water cooling or ducted air cooling.
Overload capacity: The motor has strong overload capacity. The overload multiple that can be sustained at the rated frequency is specified in the technical data table of the selection sample for a duration of 1 minute.
Terminal direction: The standard terminal direction is "right terminal" (viewed from the shaft extension end). It can be changed to "left terminal" or "top terminal" as per user requirements. Motor accessories: Optional motor internal windings, temperature sensors or temperature protection switches for both shaft extension end and non-shaft extension end. Additional options include internal space heaters. The non-shaft extension end can be equipped with accessories such as encoders, overspeed switches, and brake actuators or be designed with dual-shaft output.
