vfd connection diagram
This is a free printable vfd connection diagram: download the diagram as SVG or open it and print to paper or PDF.
Diagram checks and scope
- Components
- 6
- Wired connections
- 10
- Automated check
- Automated pin, route, source, and topology checks passed; this is not a safety certification.
A VFD connection diagram shows how electronic motor speed controllers integrate into industrial three-phase circuits. The diagram illustrates input power connection, rectifier-inverter topology, motor terminal connections, and safety elements including main disconnect switch and input fuses.
How to wire vfd connection diagram
- Isolate and lock out the supply Switch off and lock out the main supply feeding the VFD installation. Verify all conductors are dead before working in the enclosure.
- Connect input power terminals Wire L1, L2, L3 from the supply through a correctly rated isolator and fusing or MCB to the VFD input terminals. Size the incoming cable and protection per the VFD input current rating on the nameplate.
- Earth the VFD chassis Connect a protective earth conductor from the VFD chassis earth terminal to the enclosure earth bar. Use a conductor cross-section per the drive manufacturer's specification — typically equal to the input phase conductors.
- Run shielded motor cable Use shielded 4-core motor cable (3 phases plus earth) from VFD output to the motor. Keep motor cable away from control and signal cables. Maximum recommended run without additional filtering is typically 50–100 m — check the VFD manual.
- Connect output to motor Connect T1/U, T2/V, T3/W to the motor terminals and earth the motor frame. Terminate the cable shield at both ends — at the VFD earth bar and at the motor terminal box.
- Wire control terminals Connect start/stop and speed reference signals using screened control cable. Keep control wiring physically separated from power wiring to prevent induced interference.
- Commission and verify rotation Power up, set parameters per the drive commissioning guide, and jog the motor briefly to verify correct rotation direction before connecting to the load.
Frequently asked questions
What is the basic wiring layout of a VFD?
A VFD has three sections: power input terminals (L1, L2, L3 for three-phase or L, N for single-phase), DC bus (internal), and power output terminals (T1/U, T2/V, T3/W) to the motor. Separate control terminals handle start/stop signals, speed reference, and status outputs.
Should I install an isolator between the VFD and the motor?
Never switch the motor while the VFD is running — switching the output under load can damage the output IGBTs. Isolation between VFD and motor is permissible only for maintenance purposes with the VFD powered down. Use a contactor on the input side, not the output side, if isolation is required.
Why must VFD motor cables be shielded?
VFD output switching produces high-frequency common-mode voltages that radiate EMI interference onto nearby cables and equipment. Shielded motor cable with the shield earthed at both ends contains this interference and prevents it from disrupting control systems and PLCs.
What happens if I connect VFD output terminals in the wrong phase sequence?
The motor will run in reverse. To correct rotation, swap any two output phase conductors (T1, T2, or T3). Do not swap phases at the motor terminals — do it at the VFD output terminals for cleaner wiring.
Does a VFD need its own earth (ground) connection?
Yes — the VFD chassis must have a dedicated low-impedance earth connection. The earth conductor must be sized correctly for the drive's output current. A poor earth causes nuisance tripping on earth fault detection and can damage the drive.
Sources and verification
Review status: Not independently reviewed. Automated topology checks confirm stored terminals and routes, not the correctness of manufacturer pin assignments, ratings, regional codes, or installation decisions. Verify those claims against the current primary documentation before use.
- IEC 61082-1:2014 — Rules for electrotechnical documents — International Electrotechnical Commission. Supports: General diagram, drawing, table, and reference-designation presentation conventions. Checked 2026-07-15.