Industrial Engineer · phase 11 of 16 · noun
Skip Frequency
Configured speed band the drive avoids during steady operation to reduce mechanical resonance.
The Explain card
- Plain English
- A skip frequency is a band of speeds the drive will pass through but never settle in. It exists to avoid a mechanical resonance that shakes the machine at one particular speed.
- Example
- A cooling tower fan rattles its structure badly between 32 and 35 hertz. A skip band across that range means the drive runs at 31 or 36 and passes through the band on its way.
- Why it matters
- Resonance at one speed can loosen bolts, crack welds and destroy bearings over months. Skip bands are the cheap fix, and they need to be set by walking the speed range and listening, since the drive cannot find the resonance for you.
- Hook
- Never stop on that step of the staircase.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During commissioning, set the Skip Frequency parameters after a vibration sweep identifies resonance near 42 Hz.
Why these words
- skip Middle English skippen, probably from Old Norse skopa marks an intentional omission or bypass
- frequency Latin frequentia, abundance or repeated occurrence names the measured quantity associated with the omission
Where it came from
- Origin
- English engineering compound formed from skip and frequency
- Entered the language
- 20th century
- What changed
- Skip broadened from leaping to passing over, while frequency developed from repeated occurrence into a measured rate of cycles.
How it is spelled
- Pattern
- The final p in skip doubles before vowel-initial suffixes, as in skipped and skipping.
- Pattern
- Frequency uses the common adjective-to-noun change from -ent to -ency.
Spelled like
- stopped
- tripping
- consistent
- consistency
Broken into chunks
-
skip
- skipped
- skipping
-
frequ
- frequent
- frequently
-
-ency
- efficiency
- consistency
What it sits beside
Same subject
- variable frequency drive
- carrier frequency
- acceleration time
- mechanical resonance
Same shape
- base frequency
- carrier frequency
- switching frequency
VFD frequency parameters
- maximum frequency
- base frequency
- carrier frequency
VFD commissioning checks
- motor rotation check
- autotune
- vibration test
Where it sits in the deck
Phase 11: VFD Control Modes and Tuning
How a drive decides what to send the motor, from plain volts per hertz up to closed loop vector control, and how each mode is tuned.
