Industrial Engineer · phase 8 of 16 · noun

Inverter

Output power stage that switches DC into variable-frequency, variable-voltage AC for the motor.

The Explain card

Plain English
The inverter is the back end of the drive. Six fast switches take the DC bus and chop it into three phases of pulses that the motor sees as AC at the commanded frequency.
Example
The drive commands 45 hertz. The inverter switches thousands of times a second to shape three sine like currents that complete 45 cycles every second in the motor windings.
Why it matters
The inverter is where the motor's voltage, frequency and current are actually made, and where most of the drive's heat and most of its expensive failures happen. An output short or a ground fault is felt first here.
Hook
DC goes in, a made to order three phase comes out.

Word knowledge

How the word is built, where it came from, and what it sits beside in memory.

In a sentence

During commissioning, the technician measured the inverter output at the motor terminals and confirmed that frequency increased with the speed reference.

How it is built
  • in- prefix in, into, or upon
  • vert root turn
  • -er suffix a person or device that performs an action
Where it came from
Origin
English invert plus -er; invert comes from Latin invertere, formed from in- and vertere, meaning to turn
Entered the language
1584
What changed
It first denoted a person or thing that inverts, then became a technical name for machines and circuits that perform inversion.
How it is spelled
Pattern
The final t of invert is retained when -er is added.
Pattern
The suffix -er forms a noun naming an agent or device from a verb.
Breaks the pattern
Invertor occurs as a less common variant, but inverter is the standard engineering spelling.

Spelled like

  • converter
  • diverter
  • reverter
Broken into chunks
  • invert
    • inverted
    • inverting
  • vert
    • convert
    • divert
What it sits beside

Same subject

  • rectifier
  • DC bus
  • IGBT
  • pulse-width modulation
  • variable frequency drive

Same shape

VFD power-path components

power conversion terms

Where it sits in the deck

Phase 8: VFD Drive Hardware and Power Path

Inside the drive: rectifier, DC bus and inverter, the three stages every variable frequency drive uses to rebuild the waveform a motor sees.

Neighbours in this phase