VFD Knowledge Center
VFD Insights & Selection Guides
Practical guidance for choosing, applying and maintaining variable frequency drives — written for pump builders, machine OEMs and industrial maintenance teams.
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VFD Wiring Basics: Power, Motor and Grounding
VFD wiring basics: input, output and PE grounding, shielded motor cable, and the mistakes that damage drives.
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EC590 vs EC6000: Which Qingtian VFD Should You Choose?
EC590 vs EC6000 compared: control modes, torque control, mounting, expansion and typical applications.
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How to Size a VFD for Your Motor
How to size a VFD: match full-load current, voltage class and overload class – not just kW.
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V/F Control vs Vector Control VFD
Compare V/F and vector control VFDs by speed accuracy, low-speed torque, wiring, commissioning, cost, and best-fit industrial applications.
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How to Select a VFD for Pump Applications
Select pump VFDs by matching motor current, system curve, torque demand, speed range, protection, sleep/wake settings, and cavitation risk.
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VFD vs Soft Starter: Which One Do You Need?
Compare starting current, speed control, energy saving, cost, and application fit before choosing between a VFD and a soft starter.
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VFD Sizing Guide: Motor kW, Current and Voltage
A practical VFD sizing method using rated current, kW, supply voltage, load type, overload demand, cable length, and duty cycle.
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How to Choose the Right VFD for Your Motor
Match a drive to the motor nameplate, supply voltage, load type, overload demand, control mode, and installation environment.