We service and repair a wide range of industrial drive systems, including variable frequency drives (VFDs).
Other drive types we service include:
- Mechanical
- Hydraulic
- Eddy-current
- Rotating DC
- Electronic DC
- Electronic AC
Most automation systems today use variable frequency drives. A VFD takes fixed AC voltage and frequency, converts it internally to DC, then produces variable-voltage, variable-frequency AC output to control motor speed and torque.
A VFD combines control electronics and power components to manage the torque, speed, and direction of an AC induction motor.
A variable frequency drive performs several key functions:
- Control circuitry coordinates the switching of power devices in the correct sequence.
- A microprocessor or digital signal processor (DSP) manages internal logic and operating decisions.
- Motor speed is controlled by adjusting voltage and frequency to match the needs of the application.
- Motor torque is maintained by controlling the relationship between voltage and frequency.
In simple terms, a VFD converts fixed electrical input into a controlled output that allows motor speed to change while maintaining the torque required by the application.
SMARTS Troubleshooting
SMARTS is a practical framework for troubleshooting drive and motor-control problems systematically.
S – Safety. Before any diagnostics begin, we make sure personnel, customers, and equipment are protected.
M – Manual. Manufacturer documentation helps interpret fault codes, diagnostic messages, settings, and operating parameters.
A – Application. We troubleshoot the entire application, not just the drive. Many drive faults are caused by conditions elsewhere in the machine or electrical system.
R – Readings. We check line voltage, motor current, temperatures, and other operating conditions to identify issues such as unstable voltage, electrical noise, overheating, or power-quality problems.
T – Talk. Operators and equipment users often provide valuable insight because they know how the machine normally behaves and what happened immediately before the fault occurred.
S – Simple Solutions. We rule out the simplest causes first before moving into more complex and costly repairs.
Common VFD Problems We Diagnose
VFDs and other industrial drives are generally reliable, and many faults originate elsewhere in the machine or electrical system rather than inside the drive itself.
- Loose or damaged connections
- Cooling fan failure and over-temperature faults
- Power semiconductor failure
- Aging electrolytic capacitors
- Programming or parameter issues
- Circuit board failures
- Overcurrent faults
- Poor incoming power quality
Circuit board failures are less common than many other causes, so experienced technicians typically rule out simpler mechanical, electrical, and programming-related issues first.
If programming is suspected, we determine whether the equipment was operating properly before settings were changed and, when appropriate, restore the previous parameters to test whether the issue is resolved.
Overcurrent is one of the most common drive faults and can have many possible causes. Troubleshooting typically begins with the motor, load, operating conditions, and surrounding electrical system before moving deeper into the drive itself.
Preventive VFD Maintenance
Routine maintenance can help reduce unexpected drive failures and extend equipment life.
- Keep drives clean and free of dust buildup.
- Maintain proper ventilation and cooling.
- Protect equipment from moisture and contamination.
- Inspect connections and cooling components regularly.
- Monitor operating temperatures and fault history.
