VFD / VSD Repair Singapore — Variable Frequency Drive Repair
Variable Frequency Drives (VFDs) and Variable Speed Drives (VSDs) are critical to motor control in pumps, fans, conveyors, compressors and HVAC systems. When a drive fails, downtime accumulates rapidly.
QC Engineering’s drive repair team performs component-level diagnosis and repair — fixing the root cause rather than simply replacing the entire unit. We support all major brands and models, including obsolete and discontinued drives.
Common VFD Fault Codes & Symptoms We Fix
- Overcurrent (OC) fault — drive trips immediately on start
- Overvoltage (OV) fault — DC bus voltage too high
- Undervoltage (UV) fault — DC bus voltage too low
- IGBT fault / output short circuit
- Output phase loss — motor runs on 2 phases only
- Overtemperature / cooling fan alarm
- Keypad or display not working
- Drive powers up but output frequency zero
- Communication fault with PLC / BMS
- Earth fault / ground fault
Service Levels
| Repair Type | Description |
|---|---|
|
Standard Service |
14-day turnaround. Full load test before return. |
|
Express Service |
3-day turnaround subject to T&Cs and parts availability. |
|
No Fix, No Fee |
No charge if we are unable to repair your drive. |
Brands We Repair
| Brands | ||
|---|---|---|
|
ABB (ACS series) |
Danfoss (FC series) |
Mitsubishi (FR series) |
|
Siemens (SINAMICS, MicroMaster) |
Schneider (Altivar) |
Yaskawa (E7, V7, G7) |
|
Fuji Electric (FRENIC) |
Emerson / Control Techniques |
Lenze |
|
Delta |
Omron (3G3) |
WEG |
VFD / VSD Repair Services
| Repair Type | Description |
|---|---|
 IGBT Module Replacement |
Replace failed IGBT power modules — the primary failure point in drives after power surges, short circuits or prolonged overcurrent events. We source OEM-equivalent modules. |
 Control Card Repair |
Repair the drive’s main control PCB — microprocessor faults, memory corruption, analogue input circuits and reference signal failures. |
 Capacitor Replacement |
Replace aged or failed DC bus electrolytic capacitors that cause voltage instability, low DC bus warnings or nuisance tripping. |
 Gate Driver Board Repair |
Repair the IGBT gate driver circuits that translate control signals to power stage — a common cause of ‘output phase loss’ faults. |
 Power Supply Board Repair |
Repair internal SMPS power supply boards that cause the drive to fail to power up or show ‘power card fault’ alarms. |
 Rectifier / Diode Bridge Repair |
Replace failed rectifier diodes or diode bridge modules causing DC bus undervoltage or unbalanced phase faults. |
 Display Panel Repair |
Repair or replace operator keypads and display panels — LCD, 7-segment and LED types supported. |
|
|
Replace failed cooling fans and clean heat exchangers to restore proper thermal performance and prevent shutdown. |
 Parameter Data Backup |
Back up all drive parameters before repair and restore them after — ensuring no machine settings are lost. |
|
Fieldbus Communication Repair |
Restore PROFIBUS, Modbus, DeviceNet, BACnet and Ethernet communication option boards. |
 Overvoltage / Overcurrent Protection Repair |
Restore tripped protection circuits and diagnose whether the root cause is the drive or connected motor/load. |
|
Soft Starter Repair |
Component-level repair of soft starters — thyristor replacement, control board repair and bypass contactor diagnosis. |
