Upgrading Fan Performance and Reliability with New VFD Installations
At Velocity Mechanical, we understand how critical consistent airflow is to the performance of any HVAC system. When a client recently called us to investigate multiple supply and return fans that weren’t running, we knew prompt diagnosis and resolution were essential to avoid further system strain and occupant discomfort.
The Diagnosis: Weak Capacitors Causing VFD Failure
Our service technician discovered that the issue stemmed from aging 1st-generation Square D variable frequency drives (VFDs). These drives showed low DC bus voltage at higher motor RPMs, a clear indicator of weak internal capacitors. This condition triggered alarms and forced the motors to shut down intermittently—causing inconsistent airflow and unnecessary downtime.
As a temporary solution, we adjusted the VFD parameters to limit the maximum motor RPM, which allowed partial system operation while a permanent fix was planned.
The Solution: Replacing Outdated VFDs with Modern, Reliable Technology
Velocity Mechanical was contracted to replace the aging VFDs with new ABB VFDs, which were carefully spec’d to meet the system's demands. We also included integrated bypass functionality to ensure continued operation even if a drive ever fails—an added layer of reliability our client values highly.
Our technicians completed the installation with precision and attention to detail, ensuring neat, safe, and code-compliant wiring and layout. As part of our commitment to quality, we also coordinated a factory startup, enabling the client to benefit from an extended manufacturer warranty and peace of mind.
The Benefits: Improved Performance, Protection, and Efficiency
The new ABB VFDs provide several advantages:
- Energy efficiency through optimized motor control
- Precise airflow regulation for improved building comfort and system balance
- Extended motor life due to reduced electrical and mechanical stress
- Bypass operation to maintain uptime during future maintenance or failures
Investing in Longevity and System Performance
This project is a great example of how Velocity Mechanical goes beyond quick fixes. By replacing aging equipment with high-efficiency, high-reliability solutions, we help our clients future-proof their HVAC systems and reduce the risk of future failures.