Industrial Engineer · phase 13 of 16 · noun
Six-Pulse Rectifier
Common three-phase diode bridge with six switching pulses per line cycle and characteristic input-current harmonics.
The Explain card
- Plain English
- The six pulse rectifier is the plain three phase diode bridge found in most drives. It makes six current pulses per line cycle, one for each pair of diodes taking its turn.
- Example
- A standard 50 horsepower drive has a six pulse front end. Its input current comes in two humps per half cycle instead of a sine, and that shape is what a harmonic meter sees.
- Why it matters
- Six pulse is cheap, rugged and the source of the fifth and seventh harmonics that dominate most plants. Everything else in the harmonic toolkit is a way of doing better than this bridge.
- Hook
- The default front end, and the default problem.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During commissioning, the engineer measured the line-side current of the six-pulse rectifier before enabling the VFD motor output.
Why these words
- six Old English siex, six specifies the count associated with the pulse pattern
- pulse Latin pulsus, a beating or stroke names the repeated electrical event used to classify the circuit
- rectifier English rectify plus -er, ultimately from Medieval Latin rectificare, to make right names the device being classified
Where it came from
- Origin
- English technical compound built from six, pulse, and rectifier
- Entered the language
- 20th century
- What changed
- Pulse moved from bodily beating to repeated electrical action, while rectifier became the device noun formed from the electrical sense of rectify.
How it is spelled
- Pattern
- A hyphen joins six and pulse because they work together as a compound modifier before rectifier.
- Pattern
- Pulse remains singular inside the compound modifier.
Spelled like
- twelve-pulse rectifier
- six-pole motor
- three-phase drive
Broken into chunks
-
six
- sixteen
- sixty
-
puls
- pulsate
- impulse
-
rect
- rectify
- correct
-
-er
- controller
- transmitter
What it sits beside
Same subject
- DC bus
- line reactor
- diode bridge
- harmonic filter
- variable frequency drive
Same shape
- twelve-pulse rectifier
- eighteen-pulse rectifier
- six-pole motor
rectifier pulse classifications
- six-pulse rectifier
- twelve-pulse rectifier
- eighteen-pulse rectifier
VFD power-path components
- rectifier
- DC-link capacitor
- inverter
Where it sits in the deck
Phase 13: VFD Power Quality, Wiring, and Motor Protection
Harmonics, reflected waves, shielded cable and bearing currents: the side effects a drive inflicts on everything around it.
