Frequently asked questions
A VFD is a device that controls the speed of an AC electric motor by varying the frequency and voltage of the power supplied to it.
You need one for applications like pumps, fans, and compressors to achieve significant energy savings, improve process control, reduce mechanical stress, and extend equipment life by matching motor output to the specific demands of a system, rather than running at full speed constantly.
A variable frequency drive (VFD) saves energy and lowers operating costs by controlling the speed of an electric motor to match the specific load, instead of running it at full speed constantly. It does this by adjusting the power's frequency and voltage, which reduces energy consumption and minimizes mechanical stress on the equipment. This precise control leads to energy savings, especially in applications like pumps and fans where the demand fluctuates, and reduces wear and tear on the motor and related components.
There are a few things worth examining when changing out a VFD with one of the same, as simple as it sounds. First and foremost is the model number as well as the voltage class and current/ HP rating. It is imperative these numbers match on both units. This also verifies dimensionally the new VFD will fit in the existing space. Next, all wiring must be landed on the same terminal designation. This ensures the input/output functionality of the new VFD equates to that of the old. Lastly, parameter settings should match which are key for the application. Thankfully, there are many forms of backup especially if the old VFD can still be powered up. If accessed, parameter settings can be written down, stored in a software program, or even saved to the keypad’s memory and transferred to the new VFD. Ideally, this should be done before the replacement process takes place. Also, in many cases when the VFD is incorporated in a bigger piece of equipment, the OEM (original equipment manufacturer) may even have their own parameter listing. Worst case is the drive will have to be setup manually and optimized for the application by the user.
A typical VFD installation can take most of a day, with the exact time varying based on the complexity and scope of the project. Factors such as site preparation, system complexity, potential need for electrical upgrades, and the final configuration and testing all contribute to the overall duration.
Factors that influence installation time
Site preparation: This can include setting up a clean worksite, laying down protective coverings, and preparing a new mounting platform for the equipment.
Electrical requirements: Verifying that the existing electrical infrastructure can support the VFD is a critical step. If upgrades are needed, this will add significant time to the project.
Demolition: If replacing an old system, the time for removing the old equipment must be factored in.
Physical installation: Mounting the new VFD, running wires, and making connections to the motor and power supply takes time.
System configuration and testing: After physical installation, the system must be carefully set up and tested to ensure it meets manufacturer specifications. This can include programming the VFD, evacuating the system to remove air and moisture, and verifying all connections and settings.
Special considerations: Some motors may require modifications, or the installation of external components like braking resistors or filters to manage harmonics, which can extend the timeline.