Another function only available on certain models is a pulse input. On this terminal, the VFD accepts a frequency range of DC voltage pulses that can be used for a variety of functions.

A typical 6-pulse VFD has six diodes as a front-end bridge rectifier that converts AC to DC. VFDs can also have 12 diodes — two sets per phase (2 × 2 × 3 = 12 pulse) — or 18 diodes — three sets per ...

Pulse-width modulation (PWM) VFDs are most commonly used in industry because of excellent input power factor due to fixed DC bus voltage, no motor cogging, higher efficiencies, and lower cost. A PWM ...

VFD Fundamentals: An Overview A typical VFD drive ... voltage in a sequence set by the controller—a process known as pulse width modulation (PWM). This defines the output AC frequency.