Industrial Engineer · phase 9 of 16 · noun
Output Current Rating
Maximum continuous motor current the drive can supply under stated overload and environmental conditions.
The Explain card
- Plain English
- The output current rating is how many amps the drive can deliver to the motor continuously, at its stated overload, temperature and switching frequency. It is the number that actually sizes a drive.
- Example
- A motor nameplate reads 27 amps full load. A drive rated 30 amps continuous covers it with a little margin, and a drive rated 24 amps will run warm and trip on hot days.
- Why it matters
- Horsepower on a drive label is a rough class, and two 20 horsepower motors can have different currents. Match amps to amps, then check the overload the application needs and whether the derating for altitude or carrier frequency eats the margin.
- Hook
- Amps, and then everything else.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During VFD selection, the engineer compares the motor nameplate amperes with the Output Current Rating in the drive data sheet.
Why these words
- output English compound of out and put identifies the drive side being described
- current Latin currere, to run, through Old French corant names the electrical quantity under consideration
- rating rate plus the noun-forming suffix -ing serves as the head noun and marks the value as an assigned equipment specification
Where it came from
- Origin
- an English technical compound combining output, current, and rating
- Entered the language
- 20th century
- What changed
- Current moved from the idea of running or flowing to electrical usage in the 18th century, while rating developed from classification into a standard engineering specification.
How it is spelled
- Pattern
- output is written as a closed compound
- Pattern
- current retains the doubled r inherited from its Latin root
- Pattern
- rating drops the final e of rate before -ing
Spelled like
- input
- concurrent
- dating
- gating
Broken into chunks
-
out
- outcome
- outflow
-
curr
- currency
- concurrent
-
rate + -ing
- dating
- gating
What it sits beside
Same subject
- motor nameplate current
- drive overload rating
- continuous current
- current limit
- VFD sizing
Same shape
- output voltage rating
- input current rating
- continuous current rating
drive nameplate ratings
- input voltage rating
- output frequency rating
- output current rating
current specifications
- continuous current rating
- overload current rating
- short-circuit current rating
Where it sits in the deck
Phase 9: VFD Ratings, Sizing, and Motor Data
Nameplate arithmetic, where the currents, voltages and duty ratings decide whether a drive can actually run the motor you bolted it to.
