Industrial Engineer · phase 14 of 16 · noun
Output Phase Loss
Detected open motor phase or severe output-current imbalance between phases.
The Explain card
- Plain English
- Output phase loss means one motor lead is open or the current in the three phases is badly unbalanced. The drive is trying to run a three phase motor on two.
- Example
- A motor terminal works loose and one phase drops out. The motor hums, draws high current on the other two phases, and the drive trips on output phase loss.
- Why it matters
- A motor single phasing overheats fast, so the trip saves the winding. The cause is nearly always a connection, a contactor, or a broken conductor, and the drive is telling you which side of itself to look on.
- Hook
- The motor is running on two legs and the drive knows it.
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 checked the VFD motor leads after the keypad displayed an Output Phase Loss fault.
Why these words
- output English out + put locates the condition on the drive's outgoing side
- phase French phase, from Greek phasis, appearance identifies the relevant part of the three-phase system
- loss Middle English los, probably back-formed from lost serves as the head noun and names the condition class
Where it came from
- Origin
- Modern English technical compound of output, phase, and loss
- Entered the language
- 20th century
- What changed
- Output broadened from production quantity to delivered power or signal, phase gained an electrical sense, and loss became the head of a drive-fault label.
How it is spelled
- Pattern
- The phrase is written as three separate words.
- Pattern
- Output is a closed compound formed from out + put.
- Pattern
- Phase keeps the Greek-derived ph spelling for the /f/ sound.
- Pattern
- Loss uses final ss after a short stressed vowel.
- Breaks the pattern
- In phase, the final e is silent and the s is pronounced /z/.
Spelled like
- input
- throughput
- phone
- moss
Broken into chunks
-
out + put
- input
- throughput
-
phase
- three-phase
- phase angle
-
loss
- power loss
- signal loss
What it sits beside
Same subject
- Input Phase Loss
- Ground Fault
- Motor Overload
- Current Imbalance
Same shape
- Input Phase Loss
- Motor Phase Loss
- Output Overcurrent
Drive protection terms
- Output Phase Loss
- Input Phase Loss
- Ground Fault
Three-phase quantities
- phase current
- phase voltage
- phase angle
Where it sits in the deck
Phase 14: VFD Safety, Faults, and Diagnostics
What a drive does when it trips, what the fault codes are telling you, and how safe torque off stops the motor without killing the panel.
