In order to contribute towards energy efficiency efforts, numerous installations in commercial sectors have added variable speed drives for operating their motors and pumps. When VFD (Variable Frequency Drive) is commissioned, there are several guidelines that differentiate between long-term and short-term installations.
Before initiating the VFD, it is important to go through the instructional manual and relevant documentation. Drive specifications for each individual device vary by type, parameters, and manufacturers. For getting started, ensure to inspect the drive to find out any damages that may have occurred during transit.
Ensure that no damage has occurred to the drive at the time of transit. Check the shipping container to ensure that it arrives in good condition along with hardware and complete documentation. The nameplate details mentioned on the drive motor should also be checked and verified against the information given on the specification sheet.
While mounting the VFD, both the physical and electrical installation tips must be considered carefully. Prior to beginning the mounting of VFD on the black Variable Frequency Drive panel, do not forget to check the specifications. Multiple VFD devices can be installed at one location; however, it is important to ensure proper circulation of air, so carefully read the instructions mentioned on the control panel.
Vertical & Horizontal Spacing
Mount the VFD drives in vertical layout. Several VFD devices can be mounted without specific clearance, but as a rule of thumb, the minimum spacing of 50 or more than 50 millimeters is required at side-to-side positioning along with vertical spacing of 100 mm to 150 mm above and below the VFD.
Line Reactors to Reduce Noise
Undoubtedly, VFD applications are noisy, but proper grounding and shielding or line reactors and filters can help resist the noise. In case if multiple drives are installed at a single location in VFD Panels, daisy-chaining the ground wire will create the ground loops. Each ground needs to be connected parallel to a single ground point. Line reactors prevent from momentary (transitory) voltages and moderates harmonics to-and-fro the drive.
Reduce Reflected Wave Damage
In order to reduce the damage of IGBT (Insulated Gate Bipolar Transistor) reflective waves, you can use the load-side reactor. Alternatively, keeping load-side output wiring of less than 75 feet in between the motor and the drive may also reduce the damage of reflective waves from IGBT.
Run/ Stop Control
Start/ Stop digital inputs are used to control the VFD device. VFDs can also be controlled using speed control signals (a 0-10 Vdc, 4-20 mA) or a predefined speed velocity programmed into the VFD or with the potentiometer analog input signal integrated within.
VFDs usually admit single-phase voltage but it cannot be used with single phase motors. A standard three-phase motor works appropriately with VFD devices, it is recommended to use a three-phase inverter duty motor as it is more energy efficient.
Apart from these, there are a number of factors and features that affects the installation of Variable Frequency Drives, therefore, it is recommended to carefully read the manuals and catalogs before getting started.