New F800 Series Drives
The new F800 series drives are primarily designed for controlling the rotational speed of fans and pumps, but they can also be used for compressors and other applications. Initially, six models were introduced, three of which have a power output of 0.75-110 kW and a supply voltage of 200-240 V, while the other three have a power output of 0.75-630 kW with 380-500 V supply.
Innovations in Control
These converters are equipped with a new feature called Advanced Optimum Excitation Control (AOEC). This feature adjusts the motor current to achieve a high level of torque on the shaft. As noted by Matt Handley, a manager at Mitsubishi in the UK, the new generation of drives is the result of a compromise between performance and efficiency.
Automatic Working Curve Detection
One of the distinct features of the new frequency converters is their ability to automatically detect the working curves of pumps using data on speed and torque. This is in contrast to other systems that only rely on the pump's operating point. The drive can determine the torque curve of the pump or fan by monitoring them, which helps avoid unwanted shutdowns due to changes in load. They can recognize both overload (for example, caused by clogging) and overloading (for instance, due to belt tension or impeller issues).
Built-in Features
The drive is equipped with a built-in PLC and two PID controllers. The 6000-step PLC, based on the Mitsubishi L series controller, supports expansion of inputs/outputs through three additional slots.
- Two PID controllers allow for effective motor and equipment control, eliminating the need for an external controller.
- PID functions include upper and lower limits for overload warnings, as well as protection against water hammer when pipes are damaged, dry run protection, and hydraulic hammer protection.
User Convenience
The drive can control multiple pumps, allowing speed adjustments for each of them. The motor pre-heating feature ensures a soft start, helping to avoid condensation issues and preventing potential freezing damage.
A "digital dial" system is also included, providing direct access to all important parameters. For advanced users, a removable six-line LCD display option is available, simplifying the setup process and allowing for the display of personalized text messages.
Monitoring and Self-Diagnostics
Critical internal components such as power capacitors and fans constantly undergo self-diagnostics to ensure predictive maintenance. Over time, the frequency converter retains data about its condition before and after a fault, which can be used for further analysis. Data can be exported via USB flash drive, which is also used for storing and importing/exporting parameters or code from the PLC.
Compatibility with Protocols
The drive supports RS-485, Modbus, and BACnet protocols, as well as support for protocols such as CC-Link, Profibus, Ethernet, EtherCAT, SSCNET III, while DeviceNet and Lonworks are available as options. The amount of measured energy savings can be output through the industrial network.
In Conclusion
The new generation of F800 series converters features dimensions and pricing similar to the previous F700 generation. Modern frequency converters can easily be upgraded to the new series. These drives are designed for continuous operation for at least ten years.