Choosing Electrical Equipment for Energy Saving
One of the most important, yet underutilized reserves for energy saving is the proper selection of main electrical equipment in uncontrolled electric drives. This pertains to the simplest and most widespread systems that consume a large amount of energy.
Motor Utilization Factor
European experts define the average utilization factor of electric motors (the ratio of average power to nominal power) at a level of 0.6. In domestic conditions, this factor often turns out to be even lower. Often, the share of energy costs for producing goods rises to exorbitant levels, leading to the unprofitability of production.
Effectiveness of Equipment Replacement
Observations indicate that significant effects can be achieved simply by replacing old motors or implementing automation systems. However, the correct solution to such tasks requires highly qualified personnel to make rational decisions. The implementation of such programs, despite significant costs, can yield results: qualified specialists have a powerful and convenient tool for quickly solving complex problems.
Reduction of Energy Losses in Motors
Since the mid-1970s, the use of energy-saving electric motors has been popularized in global practice. The idea is to invest 25-30% more active materials (aluminum, iron, copper) in asynchronous motors, leading to a 30% reduction in energy losses and an increase in efficiency by up to 5% in small motors and up to 1% in powerful ones (70-100 kW).
There are many publications confirming the advantages of energy-saving motors; in particular, it is believed that if all motors in Europe were replaced with energy-saving ones, it would save electricity equivalent to shutting down six power plants with a capacity of 500 MW. However, this approach has its nuances.
Energy Saving Issues
- High losses in assemblies. Saving a few percentage points on losses in the motor cannot reduce significant losses in other elements of the equipment.
- Calculated savings. The effect will be noticeable only under stable load; while significant load fluctuations (for example, with a high share of idle running) will result in lower savings.
- Proper equipment selection. Savings are possible with the correct selection and adjustment of all system elements. For instance, losses in belt drives can vary from 5% to 12% due to incorrect parameter selection.
Reduction of Losses in Power Networks
Power losses are also associated with a low power factor. The issue of reactive power compensation is significant in domestic practice, where various technical solutions are employed to enhance system efficiency.
Additional Methods of Energy Saving in Uncontrolled Electric Drives:
- Reducing idle time.
- Switching windings for low loads.
- Changing the type of braking in systems with frequent starts and stops.
Transition to Controlled Electric Drive
This transition is a key direction for energy saving, which ensures the greatest electricity savings and improves technological processes. Thus, regulated voltage and frequency in asynchronous motors allow optimizing consumed power while reducing losses in valves.
In many technologies, there is the opportunity to control both output parameters, which ensures optimal operating modes, thereby reducing technological losses.
Modern Trends in Electric Drives
By the mid-1980s, the main solution for controlled electric drives were direct current motors, which had low reliability and high costs. Today, the situation has changed: the market has seen the emergence of cutting-edge variable frequency drives that radically transform electric drive control technologies.
These devices, including PWM inverters, provide new opportunities, including reliable protection and management capabilities, making them the primary means of implementing high-quality controlled asynchronous electric drives.
The situation with thyristor regulators highlights their limited use for prolonged regulation, while effective electronic solutions are gaining popularity and are actively being implemented in industry.
Therefore, the electronic frequency converter combined with asynchronous motors provides the potential for significant savings of active materials and cost reductions due to new technologies, ensuring further development of controlled electric drives in the coming years.