Use of Electric Motors in Production
Today, many enterprises use electric motors, which can be either asynchronous or synchronous. The main advantage of such motors is significant savings on labor, as no human effort is required to create motion - mechanical energy is generated by converting electrical energy.
Problems of Operating Mode Invariance
For specific tasks that require different rotor speeds of the electric machine, difficulties often arise. For a long time, devices were built in such a way that changing the operating mode was impossible when changing the system parameters. For example, a stationary grinding machine powered by an asynchronous motor can cut material, but lower speeds are required for fine polishing. Since the AC frequency in household networks is fixed (50 or 60 Hz), a frequency converter is necessary to change the speed.
Advantages of the Frequency Converter
A frequency converter can transform the current frequency in the range of 1 to 800 Hz. With its use, it is possible to adjust the motor speed, which expands the range of tasks performed.
Economic Benefits of the Frequency Regulator
The economic sense of implementing a frequency regulator lies in the possibility of performing various tasks on one machine, which saves time, effort, materials, and money on manufacturing a separate tool for each task.
Example of Electric Motors in Pumping Systems
Electric motors are also used in pumping units for centralized water supply systems. Without a frequency regulator, the pump draws water and increases its pressure (Δ1) to a fixed value (P). An increased pressure (Δ2) is created at the outlet, equal to the sum of the source water pressure and the value added by the pump. However, the increased pressure can be compensated by water consumption by subscribers, causing the pressure to drop to an acceptable level.
Solving the Pressure Problem
Installing a frequency regulator system in combination with a PID controller allows for the adjustment of the electric motor's operation to maintain optimal output pressure. This mode of operation of the system can be called situational.
Conclusion
The implementation of systems with frequency-controlled drives in enterprises allows for significant resource savings: electricity consumption decreases, and costs for replacement and repair of equipment that wears out due to operation in a non-situational mode are minimized.