Industrial Engineer · phase 8 of 16 · noun

DC Bus Capacitor

Capacitor bank that reduces DC-link ripple and supplies short-term energy to the inverter.

The Explain card

Plain English: The bus capacitors are the large cans across the DC link. They smooth the ripple left by the rectifier and hand the inverter bursts of current faster than the line can supply them.
Example: A motor accelerates and the inverter pulls a surge. The capacitors supply it for a few milliseconds while the rectifier catches up, and the bus voltage dips only slightly.
Why it matters: Electrolytic capacitors dry out with heat and time, and a drive that has sat unpowered for years needs its capacitors reformed slowly or they fail on the first power up. They are also why the bus stays lethal after the disconnect opens.
Hook: The part of the drive that ages.

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

In a sentence

During VFD commissioning, the technician measures ripple across the DC bus capacitor to assess the rectifier and inverter power path.

Why these words

DC English initialism of direct current specifies the electrical regime
bus English electrical shortening of busbar, ultimately from Latin omnibus, for all identifies the shared power conductor
capacitor English capacitance plus the device suffix -or names the component class

Where it came from

Origin: English engineering compound formed from DC, bus, and capacitor
Entered the language: 20th century
What changed: Bus narrowed from shared transport to a shared electrical conductor, while capacitor replaced the older technical term condenser.

How it is spelled

Spelled like

Broken into chunks

What it sits beside

Same subject

Same shape

VFD power stages

DC-link components

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.