Industry Insight
Technical notes and industry news that help you specify and run a variable frequency drive (VFD): selection guidance, commissioning experience, fault diagnosis and the standards that apply.
Published: How to Size a VFD for Centrifugal Pumps (Step-by-Step)Pump affinity laws, the correct current margin, and a commissioning checklist — a practical guide to sizing a variable frequency drive for centrifugal pumps so you avoid oversizing the drive or tripping on start.
Published: VFD Harmonics and THD: What They Are and How to Reduce ThemVariable frequency drives are non-linear loads: they draw current in pulses and send harmonics back into the supply. This note explains which THD figure actually matters, where it must be measured, and how DC reactors, line reactors and 12-pulse rectifiers differ in cost and effect.
Published: Motor Cable Length and VFDs: When You Need a dv/dt or Sine FilterLong cable runs between a drive and its motor create reflected-wave overvoltages that attack winding insulation. Cable length, switching frequency and motor insulation class together decide whether you need a dv/dt filter, a sine filter — or nothing at all.
Published: VFD vs Soft Starter: When to Choose EachA plain-language comparison of variable frequency drives and soft starters: where each pays off, first-cost vs lifetime energy, and the three questions that decide the right choice for your motor.
Published: Regenerative Braking: Brake Resistor or Regenerative Front End?When a motor brakes a high-inertia load it pushes energy back into the DC bus. A brake resistor burns that energy as heat; a regenerative front end returns it to the grid. The right answer depends on duty cycle, panel heat and whether you pay for the energy twice.
Published: IP21, IP54 or IP65: Choosing the Right VFD EnclosureThe IP rating decides where a drive can live and how it must be cooled. This note maps IP21, IP54 and IP65 drives to real plant conditions and explains why a sealed drive usually needs derating instead of a bigger fan.
Published: MPPT vs Fixed-Voltage Solar Pumping: Which Wins?Why MPPT beats fixed-voltage solar pumping on cloudy days and partial shading, plus wiring and battery-less design rules that keep a solar pump running reliably through the season.
Published: Calculating VFD Energy Savings and Payback in Four StepsVFD savings are never a fixed percentage — they follow the torque curve of the load. Here is a four-step method to estimate annual kWh, annual saving and payback for fan, pump and compressor duty using the affinity laws and your own tariff.
Published: RS485 Modbus or Modbus TCP? Wiring a VFD into a Control SystemSerial RS485 Modbus RTU still carries most drive integration, but Ethernet is gaining fast. Comparing cable, distance, polling speed and cost helps you specify the right port on the purchase order instead of paying for a gateway later.
Published: VFD Fault Codes Decoded: OC, OV, OL and What They Really MeanNearly every drive trip belongs to one of four families: overcurrent, overvoltage, overload or overtemperature. Diagnosing them in the right order turns an alarming red display into a five-minute check with a meter.