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137+Faults
30+Parameters
8Brands
40+Manuals
🚨 Quick Access by Brand
ACS
ACS Series Drives
ACS310 · ACS355 · ACS550 · ACS580
Faults
MM/
G120
G120
MM / G-Series Drives
MM440 · G120 · G120C · V20
Faults
V1K/
GA700
GA700
A-Series Drives
V1000 · A1000 · GA700 · P1000
Faults
VLT
FC
FC
VLT FC-Series
FC102 · FC202 · FC302 · FC301
Faults
DELTA
VFD-M/E Series
VFD-M · VFD-E · C2000 · MS300
Faults
SCHNEI
DER
DER
ATV Series Drives
ATV312 · ATV320 · ATV630 · ATV930
Faults
FR
SRS
SRS
FR-Series Drives
FR-D700 · FR-E700 · FR-A700 · FR-A800
Faults
PF
SRS
SRS
PowerFlex Series
PF4 · PF40 · PF525 · PF755
Faults
⚙️ Quick Tools
Calculator
FLC, torque, VFD size
Wiring
Power & control terminals
VFD Selector
Right drive for your load
Parameters
Settings explained simply
⚖️ Authorship & Copyright
Original Content — All fault descriptions, causes, fix steps, parameter guides, checklist items and PM schedules in this app are written entirely from original field experience. No text has been copied from any manufacturer manual or technical document.
Fault Code IDs — Fault code numbers and drive series model names (ACS, VLT, FR, ATV, PowerFlex etc.) are industry-standard technical reference identifiers, not creative works.
Trademarks — All product and brand names belong to their respective owners. VFD Pro is an independent reference tool, not affiliated with or endorsed by any manufacturer.
📅 Content authored: 16 March 2026 | For official documentation visit the Manuals section
📋 IMPORTANT — About Fault Code Information
All fault code numbers, names, causes and step-by-step fix guidance in this app are written entirely in our own plain-language interpretation for quick field reference. This content is not sourced from, endorsed by, or affiliated with any drive manufacturer.
Fault code identifiers (e.g. F0001, oC, alarm 13) are standard technical reference codes used industry-wide. Drive series names (ACS, VLT FC, FR, ATV, PowerFlex, G120 etc.) are product family model identifiers used solely to indicate fault code compatibility — they are not brand endorsements. All trademarks are property of their respective owners.
For complete, authoritative and warranty-valid guidance, always consult the official product manual for your specific drive model and firmware version. Direct links to official manufacturer documentation portals are provided in the Manuals section of this app.
Fault code identifiers (e.g. F0001, oC, alarm 13) are standard technical reference codes used industry-wide. Drive series names (ACS, VLT FC, FR, ATV, PowerFlex, G120 etc.) are product family model identifiers used solely to indicate fault code compatibility — they are not brand endorsements. All trademarks are property of their respective owners.
For complete, authoritative and warranty-valid guidance, always consult the official product manual for your specific drive model and firmware version. Direct links to official manufacturer documentation portals are provided in the Manuals section of this app.
Fault Codes Identify and fix VFD faults quickly
ℹ️ Reference Notice —
All fault code descriptions, causes and fix steps in this app are written in our own plain-language interpretation for quick field reference only. They are not sourced from, endorsed by, or affiliated with any manufacturer. Drive series model names are used only for fault code compatibility identification. All trademarks belong to their respective owners. For complete and authoritative information always refer to the official product manual. Official documentation links are available in the Manuals section →
🔍 Enter Fault Code
Type the code shown on the drive display and select your brand
📋 Fault Reference List
Parameters VFD settings explained in plain language
All
Basic
Motor Data
Control
Protection
Comms
Wiring Diagrams Terminal connections & layouts
⚠️ Always switch off and lock out before wiring. DC capacitors hold dangerous charge for 5+ minutes after power off. Confirm with a voltage tester before touching any terminals.
⚡ Power Terminals — Standard 3-Phase VFD
R/L1Phase R Input3-phase AC supply — Line 1
S/L2Phase S Input3-phase AC supply — Line 2
T/L3Phase T Input3-phase AC supply — Line 3
U/T1Phase U OutputTo motor terminal U1
V/T2Phase V OutputTo motor terminal V1
W/T3Phase W OutputTo motor terminal W1
PEEarth / GroundConnect to drive chassis & motor frame
⚠️ Control wiring carries low voltage (typically 10–24V DC). Use shielded cable. Keep away from power cables. Ground shield at one end only.
🔧 Control Terminal Layout (Standard)
+10VReference Supply10V DC reference for speed potentiometer
AI1Analog Input 1Speed reference — 0–10V or 4–20mA
AI2Analog Input 2Second analog input — PID feedback, PTC
AO1Analog Output0–10V output — actual frequency or current
DI1Digital Input 1Start / Run command (24V DC active)
DI2Digital Input 2Forward / Reverse direction select
DI3Digital Input 3Fault reset / External fault
COMCommon / GNDCommon reference for digital inputs
RO1ARelay Output NONormally Open — closes on run or fault
RO1BRelay Output NCNormally Closed — opens on fault
RO1CRelay CommonCommon relay terminal
📌 3-Wire Start/Stop Control (Push-Button)
DI1 → START button (N/O momentary)
DI2 → STOP button (N/C momentary)
DI3 → FORWARD / REVERSE toggle switch
COM → Common 0V for all digital inputs
+24V → 24V DC internal supply (from drive)
DI2 → STOP button (N/C momentary)
DI3 → FORWARD / REVERSE toggle switch
COM → Common 0V for all digital inputs
+24V → 24V DC internal supply (from drive)
ℹ️ RS485 Modbus RTU is the most common industrial communication interface on VFDs. Use twisted-pair shielded cable. Maximum 32 devices per segment. Terminate both ends with 120Ω resistors.
📡 RS485 Modbus RTU Wiring
A+RS485 Data A+Positive data line — connect all A+ together in daisy-chain
B−RS485 Data B−Negative data line — connect all B− together in daisy-chain
GNDScreen / ShieldConnect cable shield to GND at PLC end only
Typical Modbus Settings:
Baud Rate: 9600 or 19200 bps
Data Bits: 8 Parity: None Stop: 1
Each drive needs a unique Slave ID (1–247)
⚡ Key registers: 0001=Speed Ref, 0002=Control Word, 0003=Status Word, 0004=Output Frequency
Baud Rate: 9600 or 19200 bps
Data Bits: 8 Parity: None Stop: 1
Each drive needs a unique Slave ID (1–247)
⚡ Key registers: 0001=Speed Ref, 0002=Control Word, 0003=Status Word, 0004=Output Frequency
⚠️ Safety wiring is critical. Incorrect STO wiring can cause unexpected motor starts. Always follow the drive's safety manual. Verify correct operation before releasing to production.
🛡️ Safe Torque Off (STO) Connections
STO1STO Channel 1+24V DC = STO active (drive enabled). Remove to disable output safely.
STO2STO Channel 2Second channel for redundancy (Safety Integrity Level 3)
SGNDSTO Ground0V reference for STO supply
⚠️ Important: STO removes gate pulses to the output transistors — it does NOT remove DC bus voltage. The motor coasts to stop. It is NOT a mechanical brake. For gravity loads (hoists, lifts), a mechanical brake is still required.
🔐 Emergency Stop Wiring (E-Stop)
Two categories of E-stop for drives:
Cat 0 — Uncontrolled stop: Remove power from drive immediately. Motor coasts. Use STO.
Cat 1 — Controlled stop: Drive ramps motor to zero, then removes power. Needs timer relay and STO.
For most industrial conveyors and fans: Cat 0 (STO) is acceptable.
For hoists, cranes and process lines: Cat 1 is required to prevent product damage on fast stop.
Cat 0 — Uncontrolled stop: Remove power from drive immediately. Motor coasts. Use STO.
Cat 1 — Controlled stop: Drive ramps motor to zero, then removes power. Needs timer relay and STO.
For most industrial conveyors and fans: Cat 0 (STO) is acceptable.
For hoists, cranes and process lines: Cat 1 is required to prevent product damage on fast stop.
Load Calculator Motor, drive & power calculations
Full Load Current (FLC)
Calculate motor full load amps from nameplate data
—
Amperes (Full Load)
3-Phase: I = P ÷ (√3 × V × PF × η)
1-Phase: I = P ÷ (V × PF × η)
1-Phase: I = P ÷ (V × PF × η)
VFD Size Selector
Calculate minimum drive rating for your motor
—
kW (minimum drive rating)
Motor Torque Calculator
Calculate shaft torque from power and speed
—
Newton-Metres (Nm)
T (Nm) = (P × 9550) ÷ N
P in kW, N in RPM
P in kW, N in RPM
Motor Speed Calculator
Synchronous speed from frequency and poles
—
RPM (Synchronous Speed)
Ns = (120 × f) ÷ Poles
Cable Size Guide
Recommended motor cable cross-section
—
mm² copper conductor
Based on IS 694 / IEC 60364
Cable rated at 1.25× FLC minimum
Cable rated at 1.25× FLC minimum
📐 Quick Reference Formulas
Motor Speed from Frequency
RPM = (120 × f) ÷ Polesf = frequency in Hz. 4-pole motor at 50Hz = 1500 RPM synchronous speed
V/f Ratio
V/f = V_rated ÷ f_ratedKeep this ratio constant below base frequency for constant torque applications
Motor Slip %
Slip% = (Ns − Nr) ÷ Ns × 100Ns = synchronous speed, Nr = actual rotor speed. Normal slip: 2–5%
kW to HP Conversion
1 HP = 0.746 kW | 1 kW = 1.341 HPMany Indian market motors are rated in HP — convert before entering in drive parameters
Power Factor from Nameplate
PF = P(kW) ÷ (√3 × V × I × 0.001)If PF is not on nameplate, use 0.85 for standard 4-pole motors as a starting estimate
Synchronous Speed vs Actual Speed
Ns = 120f ÷ P | Slip% = (Ns−Nr)÷Ns × 1004-pole 50Hz: Ns=1500, Nr≈1450 RPM (slip≈3.3%). Higher slip = more torque = more heat in rotor
Braking Resistor Minimum Ohms
R(min) = Vdc² ÷ P_brake(W)Vdc = DC bus voltage (560V for 400V drive). P_brake = drive kW rating. Result is minimum safe resistance in Ohms
Speed at Different Frequency
RPM_new = RPM_rated × (f_new ÷ f_rated)Example: 1450 RPM motor at 35Hz → 1450 × (35÷50) = 1015 RPM. Valid below base frequency only
Motor Insulation Pass/Fail (Megger)
>100 MΩ = Excellent | >1 MΩ = Pass | <1 MΩ = Fail — do not runTest at 500V DC. Values drop when motor is hot — test cold for consistency. Trend matters as much as absolute value
Cable Voltage Drop (3-phase)
ΔV(V) = √3 × I × L × ρ ÷ AI=amps, L=one-way length(m), ρ=0.0175 for copper, A=cross-section(mm²). Keep VFD output cable drop below 2%
VFD Selector Choose the right drive for your application
🎯 Application-Based Selection
Select your application to get drive recommendations
📋 How to Select a VFD
Identify Load Type
Torque vs speed curve
Variable Torque: Torque increases with speed (pumps, fans). Drive can match motor kW exactly.
Constant Torque: Full torque from zero speed (conveyors, hoists, extruders). Drive must be 1.1–1.25× motor kW.
High Starting Torque: Big inertia or heavy loads (crushers, centrifuges). Drive must be 1.5× or more.
Constant Torque: Full torque from zero speed (conveyors, hoists, extruders). Drive must be 1.1–1.25× motor kW.
High Starting Torque: Big inertia or heavy loads (crushers, centrifuges). Drive must be 1.5× or more.
Variable TorqueConstant TorqueHigh Inertia
Control Mode Selection
V/f vs Vector Control
V/f (Scalar) Mode: Best for simple fan/pump. No motor speed feedback needed. Easy to set up.
Sensorless Vector: Better torque at low speed. Good for conveyors, compressors, mixers. No encoder needed.
Closed Loop Vector: Best speed accuracy and torque response. Needs encoder. Use for hoists, machine tools.
Sensorless Vector: Better torque at low speed. Good for conveyors, compressors, mixers. No encoder needed.
Closed Loop Vector: Best speed accuracy and torque response. Needs encoder. Use for hoists, machine tools.
V/f ControlSensorless VectorClosed Loop
Environment & Enclosure
IP rating, temperature, altitude
IP20/IP21: Indoor clean dry environment. Mount inside switchboard panel.
IP55/IP65: Outdoor or wet/dusty areas. Wall-mount without panel. Costs more but easier to install near machine.
Altitude derating: Above 1000m — derate drive output by 1% per 100m extra.
Temperature: Most drives rated to 40°C. Above 40°C — derate or select next size up.
IP55/IP65: Outdoor or wet/dusty areas. Wall-mount without panel. Costs more but easier to install near machine.
Altitude derating: Above 1000m — derate drive output by 1% per 100m extra.
Temperature: Most drives rated to 40°C. Above 40°C — derate or select next size up.
Brand Manuals Official documentation links — always up to date
8Brands
40+Links
FreeAccess
OfficialSource
✅ All links open official manufacturer websites or ManualsLib (a trusted manual archive). If OPEN ↗ does not work, tap 🔍 SEARCH to find the latest PDF on Google. Manufacturers sometimes move their download pages — SEARCH always finds the current location.
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🛠️ Commissioning Tools
- 📋Pre-commissioning ChecklistStep-by-step checklist for safe first power-up
- ⚙️Application Parameter TemplatesReady-made settings for pump, fan, conveyor, hoist, compressor
- 🚀First Run Startup GuideGuided 10-step procedure from no-load trial to full load
📊 Maintenance Tools
- 🔧Preventive Maintenance ScheduleMonthly, 6-month and yearly PM task lists
- 🩺Motor Health TrackerLog insulation readings and track motor health over time
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⭐ Pro Tools
Pre-Commission Checklist
Safe startup guide
Parameter Templates
App-specific settings
Site Fault Log
Record fault history
PM Schedule
Maintenance tasks
First Run Guide
Step-by-step startup
Motor Health
Insulation tracker
📋 Pre-Commissioning Checklist
Tap each item to mark as complete. Complete all checks before first power-on.
⚙️ Parameter Templates
Select application type to see recommended parameter starting points.
📓 Site Fault Log
LOG NEW FAULT
🔧 Preventive Maintenance
Tap each task to mark as done. Share with your maintenance team.
🚀 First Run Startup Guide
🩺 Motor Health Tracker
LOG INSULATION READING
INSULATION HEALTH REFERENCE
● >100 MΩ — Excellent — New or recently rewound motor
● 10–100 MΩ — Good — Normal working condition
● 1–10 MΩ — Fair — Monitor closely, plan maintenance
● 0.1–1 MΩ — Poor — Schedule rewind or replacement soon
● <0.1 MΩ — Critical — Do NOT energise
● 10–100 MΩ — Good — Normal working condition
● 1–10 MΩ — Fair — Monitor closely, plan maintenance
● 0.1–1 MΩ — Poor — Schedule rewind or replacement soon
● <0.1 MΩ — Critical — Do NOT energise