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VFD Specialists

AC Drive Repair

Component-level AC variable frequency drive repair for all major brands — fast turnaround, full load tested, warranted.

5,000+
AC Drives Repaired
98%
Success Rate
48hrs
Avg Turnaround
14+
Brands Serviced
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India's #1 AC drive repair specialists. Our schematic-driven approach, 2M+ component inventory, and dedicated VFD test benches mean your drive is diagnosed scientifically and repaired at the component level — not replaced with guesswork.

5,000+
AC Drives Repaired
98%
First-Fix Rate
48 hrs
Avg Turnaround
500 kW
Max Drive Rating
14+
Brands Covered
6 mo
Warranty
Overview

Synchronics is India's leading specialist in AC drive and VFD repair. Our dedicated drive repair team handles everything from small fractional kW drives to large 500kW+ industrial drives. We repair at the component level — IGBT modules, gate driver boards, control cards, power boards, capacitor banks — ensuring a proper fix rather than a temporary workaround.

IGBT Module Replacement
Genuine IGBT replacement with thermal interface renewal and full load verification.
Gate Driver Repair
Gate driver circuit diagnosis — optocouplers, pulse transformers, dead-time circuits.
Control Card Repair
Microcontroller, DSP, FPGA, and control logic board component-level repair.
Power Board Repair
Rectifier bridge, DC bus capacitors, charging circuit, and pre-charge resistor repair.
Parameter Backup & Restore
Drive parameters backed up before repair and restored to customer specification.
Full Load Bank Test
Every repaired drive load tested at rated current with thermal imaging verification.

What is an AC Drive?

An AC drive, also called a variable frequency drive (VFD) or inverter, is an electronic power controller that adjusts the speed and torque of AC electric motors by varying the frequency and voltage of the power supply. AC drives are critical components in industrial automation, used in applications ranging from conveyor systems and pumps to HVAC and manufacturing lines. When an AC drive fails, it can halt entire production lines — costing manufacturers thousands per hour in downtime.

Also known as: variable frequency drive, VFD, frequency inverter, adjustable speed drive

Diagnosis Guide

Common AC Drive Problems We Fix

Experiencing any of these symptoms? Our engineers have diagnosed and repaired thousands of these faults.

critical

Blown IGBT Modules

Symptom

Drive trips on overcurrent, no output to motor, short-circuit alarm

Common Cause

Overvoltage spikes, motor winding short, load jam

critical

DC Bus Capacitor Failure

Symptom

DC bus voltage unstable, undervoltage trip, humming noise from capacitor bank

Common Cause

Ageing electrolytic capacitors, high ambient temperature, voltage stress

high

Gate Driver Circuit Fault

Symptom

IGBT not switching properly, distorted output waveform, intermittent tripping

Common Cause

Optocoupler degradation, gate resistor failure, pulse transformer open

high

Control Card Failure

Symptom

No display, communication loss, parameter corruption, erratic behaviour

Common Cause

Power surge, firmware corruption, component ageing, ESD damage

critical

Rectifier Bridge Failure

Symptom

No DC bus voltage, drive does not power up, input fuse blown

Common Cause

Input power surge, lightning strike, phase imbalance

moderate

Cooling Fan Failure

Symptom

Drive overheats, thermal alarm, reduced output derating

Common Cause

Fan bearing wear, dust accumulation, blocked airflow paths

How It Works

Our AC Drive Repair Process

A systematic, schematic-driven repair process — from receipt to dispatch.

01
STEP 01

Receive & Visual Inspect

Drive is logged in our ERP system, photographed, and visually inspected for obvious damage — burnt components, swollen capacitors, loose connections.

ERP loggedPhotographedVisual check
02
STEP 02

Power-Up & Fault Diagnosis

Safe power-up on isolated supply with oscilloscope monitoring. Gate signals, DC bus voltage, and control card outputs are measured against schematic reference values.

Isolated power-upScope analysisSchematic reference
03
STEP 03

Component-Level Repair

Failed components identified from diagnosis are replaced — IGBTs, gate drivers, capacitors, optocouplers — using genuine or equivalent-spec parts from our 2M+ inventory.

Genuine partsComponent-levelInventory sourced
04
STEP 04

Parameter Restore & Config

Drive parameters restored from backup or factory defaults. Motor parameters, accel/decel ramps, and protection settings configured per customer specification.

Parameter restoreCustomer configProtection setup
05
STEP 05

Full Load Bank Test

Repaired drive connected to our load bank and tested at rated current and voltage. Thermal performance verified with infrared imaging under sustained load.

Rated load testThermal imagingPerformance verified
06
STEP 06

QA Sign-Off & Dispatch

Final QA inspection, test report generated, 6-month warranty certificate issued. Drive professionally packed and dispatched within 24 hours.

6-month warrantyTest reportNext-day dispatch

Thorough Inspection

What We Inspect in Every AC Drive

Every unit goes through a comprehensive inspection checklist before and after repair.

IGBT Power Stage

Gate-emitter voltage
Collector-emitter saturation
Thermal paste condition
Heatsink mounting torque
Snubber circuit

DC Bus Section

Capacitor ESR measurement
Capacitance value check
Bus voltage ripple
Charging resistor
Bleeder circuit

Rectifier Input

Diode forward voltage
Reverse leakage test
Soft-charge relay
Input fuse condition
EMC filter

Control Board

DSP/MCU functionality
Crystal oscillator
EEPROM integrity
Analog feedback circuits
Communication ports

Gate Driver Circuit

Optocoupler transfer ratio
Gate pulse shape & timing
Dead-time verification
Isolation voltage
Desat protection

Cooling System

Fan operation & RPM
Heatsink thermal contact
Air filter condition
Temperature sensors
Thermal shutdown threshold

The Synchronics Advantage

Why Choose Us for AC Drive Repair

Schematic-Driven Diagnosis

Every AC drive repair starts with the complete circuit schematic. Our 15,000+ schematic library means we understand the circuit before touching a single component.

Fastest Turnaround in India

Most AC drive repairs completed within 48 hours. Emergency same-day service available for critical production lines that cannot afford downtime.

Full Load Bank Testing

Every repaired drive is tested at rated load current on our dedicated VFD test benches — handling drives up to 500kW capacity.

Troubleshooting

Common AC Drive Fault Codes We Fix

Seeing one of these error codes? We diagnose and repair the root cause.

OC / E.OC
Meaning

Overcurrent during acceleration or deceleration

Possible Cause

IGBT failure, motor winding short, mechanical load jam

OV / E.OV
Meaning

DC bus overvoltage detected

Possible Cause

Regenerative energy, braking resistor open, decel time too short

UV / E.UV1
Meaning

DC bus undervoltage

Possible Cause

Input power loss, capacitor bank degradation, charging circuit fault

OH / E.OH
Meaning

Drive overheating / thermal fault

Possible Cause

Cooling fan failure, blocked airflow, high ambient temperature

GF / E.GF
Meaning

Ground fault detected at output

Possible Cause

Motor insulation breakdown, cable damage, moisture ingress

SC / E.SC
Meaning

Short circuit at output terminals

Possible Cause

IGBT shoot-through, motor winding short, output cable short

Fault codes vary by manufacturer (ABB ACS, Siemens Sinamics, Danfoss VLT, etc.). Contact us with your specific drive model and fault code for expert diagnosis.

Industries Served

Where AC Drives Are Used

Cement & Mining

Kiln drives, crusher motors, conveyor systems

Water & Wastewater

Pump VFDs, blower drives, aeration systems

HVAC & Building

AHU fans, chiller compressors, elevator drives

Steel & Metals

Rolling mill drives, furnace blowers, crane hoists

Food & Pharma

Mixer drives, conveyor VFDs, packaging machines

Oil & Gas

Compressor drives, pump stations, pipeline motors

Trusted Brands

Brands We Service

Component-level repair for all major manufacturers

FAQ

Frequently Asked Questions

Most AC drive repairs are completed within 48-72 hours after receipt. Complex faults or rare component sourcing may take slightly longer. We provide an estimated turnaround with the repair quotation.

Yes — IGBT module replacement is one of our most common repairs. We use genuine or equivalent-spec IGBT modules and always investigate the root cause of the IGBT failure to prevent recurrence.

Yes. All repaired AC drives come with a written 6-month warranty. If the same fault recurs within the warranty period, we repair it free of charge.

Yes. We regularly repair drives up to 500kW and beyond. Our load bank can test drives at full rated current to ensure the repair is validated under real operating conditions.

Yes. We always attempt to back up drive parameters before starting any repair work. After repair, parameters are restored to your original or factory specification.

AC Drive Repair Services Across India

Synchronics provides expert AC drive repair services for industries across India — Vadodara, Ahmedabad, Mumbai, Pune, Chennai, Bangalore, Delhi, Kolkata, and all major industrial cities. Our pan-India logistics network ensures your AC drive reaches our facility safely and is returned promptly after repair.

Whether you have a small 0.37kW AC drive from a packaging machine or a large 500kW drive from a cement plant, our team of 180+ engineers has the expertise and infrastructure to diagnose and repair it at the component level. We service all brands including ABB ACS, Siemens Sinamics, Schneider Altivar, Danfoss VLT, Yaskawa, Delta, and many more.

Trusted Since 1994 · ISO Certified · 32+ Years

Get Your Equipment
Back in Action — Fast

Send us your faulty industrial electronics. Our engineers will diagnose it and provide a detailed quote within 24 hours — with no obligation to proceed.

Free Evaluation

No obligation

48hr Turnaround

Fastest in India

🛡

6-Month Warranty

Every repair

No Fix, No Charge

Zero risk policy

📦

Pan-India Pickup

Doorstep service