Industrial Engineer · phase 11 of 16 · noun
Flying Start / Catch on the Fly
Function that detects the speed and direction of a spinning motor before smoothly taking control.
The Explain card
- Plain English
- Flying start lets the drive take control of a motor that is already spinning. It searches for the motor's speed and direction, matches its output to them, and then ramps to the setpoint.
- Example
- A fan is windmilling backwards in a duct when a run command arrives. With flying start the drive finds it turning in reverse, catches it, and brings it around smoothly.
- Why it matters
- Without it the drive starts at zero hertz against a spinning motor, which is an instant overcurrent or overvoltage trip. Fans, pumps in a manifold and anything restarted after a brief power loss usually need it enabled.
- Hook
- Catch the motor where it is, then take it where you want it.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
After a brief power interruption, the technician enables Flying Start on the VFD before restarting the still-rotating induced-draft fan.
Why these words
- flying Old English flēogan, to fly present participle used attributively to mark motion already underway
- start Old English styrtan, to leap up head noun naming a beginning or resumption
Where it came from
- Origin
- English compound of flying and start
- Entered the language
- 1851
- What changed
- The motion-based racing sense broadened to an advantageous beginning, then entered drive terminology as a restart label.
How it is spelled
- Pattern
- The open compound is written as two words.
- Pattern
- The final y in fly remains before the suffix -ing.
Spelled like
- crying
- trying
- running start
- standing start
Broken into chunks
-
fly-ing
- crying
- trying
-
start
- starter
- restart
What it sits beside
Same subject
- variable frequency drive
- speed search
- motor restart
- coast stop
Same shape
- running start
- standing start
- rolling start
VFD restart terms
- Flying Start
- Catch on the Fly
- speed search
motor stopping methods
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.
