Variable frequency drive symbol
Also called VFD, VSD, Variable speed drive, Frequency converter
A variable frequency drive feeds a motor at a variable frequency and voltage, so its speed can be controlled.
What the variable frequency drive symbol means
A variable frequency drive feeds a motor at a variable frequency and voltage, so its speed can be controlled.
ANSI and IEC symbols
Where you see it
Pumps, fans and compressors that need speed control, and soft starting of large motors.
What is written next to it
On a one-line, the variable frequency drive carries its tag and its ratings: rating in kW, input and output voltage and output current.
What gets checked at commissioning
Before the variable frequency drive is energised, the test records usually cover: parameters against the motor data, inputs, outputs and interlocks, then runs with the motor uncoupled and coupled. Each check is recorded against the tag, so the system can be handed over with its evidence. See commissioning software.
Related symbols
Frequently asked questions
What does the variable frequency drive symbol look like?
On ANSI drawings: A box marked VFD or VSD with its rating. In IEC 60617: The converter square with a diagonal, with alternating current on both sides: a frequency converter.
Is the variable frequency drive symbol the same in IEC and ANSI?
No. The converter square with a diagonal, with alternating current on both sides: a frequency converter. The IEC 60617 number is S00213.
Where is a variable frequency drive used?
Pumps, fans and compressors that need speed control, and soft starting of large motors.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016