When using a VFD, a motor's ramp-up speed can be adjusted to vary from a few seconds to more than how many seconds?

• A. 60 seconds
• B. 120 seconds
• C. 180 seconds
• D. 240 seconds

Answer: (B)

When you use a VFD, the ramp-up time controls how quickly the motor frequency increases from zero to the commanded speed. This makes starts smoother, reduces inrush current, and minimizes mechanical stress on the motor and drive. The typical maximum ramp time you'll encounter on many VFDs is about 120 seconds, so you can set the acceleration anywhere from a few seconds up to roughly two minutes. This is why the correct choice is 120 seconds. Longer ramp times are less common on standard drives, while shorter times reduce the smoothing effect.