How to choose the appropriate motor based on its specifications

1、 Main indicators of Hengli motor

1. Efficiency η: The ratio of the output mechanical power of an electric motor to the input power, usually expressed as a percentage.

2. Power factor cos φ: the ratio of the effective power input to the apparent power of the motor.

3. Locked rotor current I1 (starting current Ist): The maximum steady-state root mean square current input from the power supply circuit of the motor at rated voltage, rated frequency, and when the rotor is blocked.

4. Blocking torque T1 (starting torque Tst): The minimum measured value of the torque generated by the motor at rated voltage, rated frequency, and when the rotor is blocked.

5. Minimum torque Tu (Tmin): The minimum steady-state asynchronous torque generated by an electric motor between zero speed and the speed corresponding to the maximum torque at rated voltage and rated frequency.

6. Maximum torque Tb (Tmax): The maximum steady-state asynchronous torque that an electric motor can generate at rated voltage and rated frequency.

7. Noise: The A-weighted sound power level (dB (A)) of the motor during steady-state no-load operation, as well as the incremental noise sound power level exceeding no-load operation during rated load operation.

8. Vibration: The effective value of the vibration rate (mm/s) of the motor during no-load steady-state operation.

2、 Performance index requirements for Hengli motors

1. Efficiency level is one of the most important technical and economic indicators of electric motors, which directly affects the effective material consumption and operating costs of electric motors. Higher operating efficiency can bring significant energy-saving effects to users, but the effective material consumption of electric motors will increase, resulting in higher costs and prices. Meanwhile, whether the higher efficiency can fully play its role is also related to the annual operating time and load rate of the motor during operation.

The operating load rate of low-voltage asynchronous motors is generally between 50% and 80%, mostly within the range of 60% to 70%. The variation of efficiency of asynchronous motors at different load rates is related to the distribution ratio of variable losses (stator and rotor winding copper losses) and constant losses (iron losses and mechanical losses) of the motor. In the total losses, variable losses increase while constant losses decrease, and the highest efficiency tends to approach the low load rate region. Therefore, when designing an electric motor, appropriately increasing the electromagnetic load will increase the variable loss, while the constant loss should be controlled as much as possible. This can enable the motor to have relatively flat efficiency characteristics over a wide range of load rates, which is beneficial for the motor to still have high efficiency at relatively low load rates.

2. Starting performance analysis of electric motors includes the entire process of connecting the motor to the power supply, from rotor blockage to reaching the rated speed. The electric motor should have sufficient locked rotor torque and minimum torque to drive the load machinery to start quickly and reach the rated speed for normal operation; At the same time, it should have sufficient maximum torque to ensure a certain overload capacity. And for the locked rotor current (or locked rotor apparent power), it should be limited to avoid excessive voltage drop caused by the power supply, which may affect the normal operation of other electrical equipment connected to the same power supply. In addition, excessive starting current will cause the motor winding to overheat and be subjected to excessive electromagnetic force impact.

The starting requirements stipulate that the motor is allowed to start continuously twice in a cold state (the motor should naturally stop between two starts), or start once in a hot state after rated operation, and specify the rotational inertia value of the load it drives.

3. The noise and vibration level analysis of electric motors is a comprehensive indicator reflecting the design, manufacturing process, assembly quality, and bearing quality of electric motors. It is also an important indicator for measuring environmental quality, and the requirements for motor noise and vibration will become increasingly strict.

3、 Key points for selecting small asynchronous motors for Hengli Motors

1. Reasonably select the type of motor based on the requirements for starting, braking, reversing, speed regulation, etc. of the mechanical load nature and production process.

2. Based on the requirements of load torque, speed variation range, and starting frequency, considering the temperature rise limit, overload capacity, and starting torque of the motor, the power of the motor should be reasonably selected to ensure a reasonable power matching, striving for safety, reliability, and economy.

3. Based on the environmental conditions of the place of use, such as temperature, humidity, dust, rainwater, gas, corrosion, and the content of flammable and explosive gases, consider necessary protection methods and select the type of protective structure for the motor.

4. Determine the voltage level of the electric motor according to the voltage standards of the enterprise power grid and the requirements for power factor.

5. Select the rated speed of the electric motor based on the maximum speed of the production machinery, the requirements for the electric transmission speed control system, and the complexity of the mechanical deceleration.

6. When choosing a motor, one should consider the price, construction cost, and operating cost of the product, striving for the best comprehensive economic benefits. In dry and clean places, it is recommended to use Y series motors with "IP23" as much as possible, because the price of this type of motor is about 70% of that of Y series motors with the same capacity as "IP44", and the manufacturer can save materials; For continuous operation and high load rates, YX series high-efficiency motors should be used to save energy and improve overall economic benefits.

7. When choosing a motor, factors that affect installation, operation, and maintenance should be considered, striving for easy installation and maintenance, and reliable operation.

8. To implement the country's technological and economic policies, actively adopt new products promoted by the state, and avoid outdated products.

Hengli Motor reminds consumers that when purchasing motors, they should analyze performance parameters based on actual needs before making a purchase. Maintain communication with business personnel as much as possible when there are special requirements.