Industrial Engineer · phase 12 of 16 · noun
DC Injection Braking
Stopping or holding method that applies DC current to the motor stator to create braking torque without regeneration.
The Explain card
- Plain English
- DC injection braking puts direct current into the motor windings. A stationary magnetic field drags on the spinning rotor and slows it, and the energy is dissipated as heat in the motor itself.
- Example
- A drive ramps a saw down to a few hertz, then injects DC for two seconds to bring the blade to a dead stop and hold it briefly. Nothing goes back to the bus.
- Why it matters
- It gives a firm stop and a short hold without a resistor. It heats the motor, so it cannot be used for long or repeatedly, and it produces no holding torque once the rotor is still, so it is never a brake for a hoist.
- Hook
- A magnetic anchor, paid for in motor heat.
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 sets the DC Injection Braking current and duration in the VFD, then verifies the induction motor stopping time.
Why these words
- DC English abbreviation of direct current specifies the electrical form used by the technique
- injection Middle French injection, from Latin iniectio, a throwing in names the controlled introduction of current into the motor circuit
- braking English brake plus the action-forming suffix -ing identifies the phrase as the name of a stopping process
Where it came from
- Origin
- English engineering compound formed from the initialism DC, the Latinate noun injection, and the verbal noun braking
- Entered the language
- 20th century
- What changed
- Injection broadened from throwing or putting something in to introducing an electrical quantity, while braking developed from the verb brake into a process noun.
How it is spelled
- Pattern
- DC remains uppercase as an initialism
- Pattern
- The three elements form an open compound with spaces
- Pattern
- Brake drops its final silent e before the suffix -ing
Spelled like
- AC dynamic braking
- DC bus charging
- making
- taking
Broken into chunks
-
DC
- AC
- VDC
-
in-ject-ion
- ejection
- projection
-
brak-ing
- brake
- braked
What it sits beside
Same subject
- dynamic braking
- regenerative braking
- coast stop
- braking resistor
Same shape
- DC bus charging
- AC line filtering
- DC link precharging
motor braking methods
- DC injection braking
- dynamic braking
- regenerative braking
- mechanical braking
VFD commissioning parameters
- braking current
- braking duration
- start frequency
Where it sits in the deck
Phase 12: VFD Commands, References, and Stopping
Starting, referencing and stopping, including the several very different things a drive can mean by the word stop.
