Industrial Engineer · phase 10 of 16 · noun
Constant Horsepower Region
Operating range above base speed where available torque falls approximately as speed rises while power remains roughly constant.
The Explain card
- Plain English
- The constant horsepower region is the range above base speed, where voltage is at its ceiling and frequency keeps rising. Torque falls roughly as speed rises, so the product, which is power, stays about the same.
- Example
- A machine tool spindle runs from 60 to 120 hertz. At the top it turns twice as fast with half the torque, and the available cutting power is unchanged.
- Why it matters
- Loads that need power rather than torque, like spindles and winders, can use this range well. The motor's mechanical limits and the drive's ability to hold the model in weak field decide how far past base you can safely go.
- Hook
- Same power, spread thinner over more speed.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During VFD commissioning, the engineer verified that the motor entered the Constant Horsepower Region after the commanded frequency exceeded the nameplate base frequency.
Why these words
- constant Latin constans, standing firm adjective modifying horsepower
- horsepower English engineering coinage popularized by James Watt in the 1780s noun forming an attributive modifier with constant
- region Latin regio, boundary or district head noun naming a bounded part of an operating envelope
Where it came from
- Origin
- English engineering phrase combining constant, horsepower, and region
- Entered the language
- 20th century
- What changed
- Constant broadened from steadfast to invariant, horsepower became a standardized engineering unit, and region specialized to a bounded operating zone.
How it is spelled
- Pattern
- horsepower is written as a closed compound
- Pattern
- constant retains the adjective ending -ant
- Pattern
- region retains the noun ending -ion
Spelled like
- manpower
- waterpower
- distant
- vacant
- rotation
- division
Broken into chunks
-
const
- constancy
- constant
-
horse + power
- horsepower
- waterpower
-
region
- regional
- regionalize
What it sits beside
Same subject
- base speed
- field weakening
- constant torque region
- torque-speed curve
- variable frequency drive
Same shape
- constant torque region
- constant power range
- field weakening region
motor operating regions
- constant torque region
- constant horsepower region
- field weakening region
drive commissioning references
- motor nameplate
- torque-speed curve
- frequency setpoint
Where it sits in the deck
Phase 10: VFD Electrical and Motor Fundamentals
The physics under the parameters: slip, torque, flux, and the relationship between frequency and voltage that every drive is really controlling.
