Compared with ordinary motors, there is not much difference between the frequency conversion motor and the ordinary motor, but there are big differences between the two in terms of performance and use. The variable frequency motor is powered by the variable frequency power supply or the inverter, and the speed of the motor can be changed, including constant torque and constant power variable frequency motor, while the ordinary motor is powered by the power frequency power supply, and its rated speed is relatively fixed.
The ordinary motor fan rotates with the motor rotor at the same time, while the variable frequency motor relies on another axial flow fan to dissipate heat. Therefore, when the ordinary fan is used with variable frequency and runs at low speed, it may burn out due to overheating.
In addition, the frequency conversion motor has to withstand high-frequency magnetic fields, so the insulation level is higher than that of ordinary motors. The frequency conversion motor slot insulation and electromagnetic wires have special requirements to improve the high-frequency shock wave tolerance.
The frequency conversion motor can adjust the speed arbitrarily within its speed regulation range, and the motor will not be damaged, while the general power frequency motor can only run under the conditions of rated voltage and rated frequency. Some motor manufacturers have designed a wide-band ordinary motor with a small adjustment range, which can ensure a small range of frequency conversion, but the range should not be too large, otherwise the motor will be overheated or even burned.
The energy saving of the frequency converter is mainly manifested in the application of fans and water pumps. In order to ensure the reliability of production, all kinds of production machinery have a certain margin when they are designed with power drives. When the motor cannot run under full load, in addition to meeting the power drive requirements, the excess torque increases the consumption of active power, resulting in a waste of electric energy. The traditional speed regulation method of fans, pumps and other equipment is to adjust the air supply and water supply by adjusting the baffles and valve openings at the inlet or outlet. The input power is large, and a lot of energy is consumed in the blocking process of the baffles and valves. middle. When using variable frequency speed regulation, if the flow requirement is reduced, the requirement can be met by reducing the speed of the pump or fan.
Frequency conversion is not everywhere to save electricity, and there are many occasions where frequency conversion does not necessarily save electricity. As an electronic circuit, the inverter itself also consumes power. The power consumption of a 1.5 hp air conditioner itself is 20-30W, which is equivalent to an ever-bright lamp. It is a fact that the inverter runs under the power frequency and has the function of saving electricity. But his prerequisites are high power and fan/pump loads, and the device itself has a power saving function.
Post time: Jul-25-2022